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1. ee 2 6 11 dB Applications 2 7 DMM SETUP PROGRAMS p xu cu Su Suk edt Cla Ld 2 71 Software Revision Level tepid ceca ous 2 7 2 Multiplexer Auto Zero Cal a su scene se ee 17 3 N74 LAS s 1 7 6 7 7 2 78 2 8 2 8 1 282 283 2 84 28 5 2 9 2 9 1 2 9 2 2 10 2 10 1 2 10 2 2 10 3 2 11 21 1 2112 2 11 3 2 114 2 11 5 2 11 6 2 11 7 2 18 2 11 9 2 11 10 211 1 21122 2113 2 11 14 2 1 5 2 11 16 FRONT PANEL TRIGGERING IEEE 488 Primary Address ie lence Line T baie eee kien o EE ud Save Setup LED Test ew ee s dere Meu A eee M esa d 2451 ree n n amp Trigger Mode Selection 5 5 m bos Trigger Sources oues T Trigger Delay wx ea a ee eee a ora ae gtd Ure UN INN a es Reading Interval odia Trigger Programming Ex
2. Terminator Y Status 2 Auto Cal Multiplex A Trigger Delay W Self Test J Hit Button Display 0 TRANSLATOR SOFTWARE Translatoe Format Wild Card 5 NEW and OLD Combining Translator Words Combining Translator Words With Keithley IEEE 488 Commands Translator Words and Keithley IEEE 8 SAVE LIST FORGET BUS DATA TRANSMISSION cc cr secnm scie tmm nee SCANNER PROGRAMMING Scanner Setup Pole Ratio Mode O Reading Interval and Delay Programming A oss Using Data Store with the Scanner Testing Resistors Amplifier Gain Testing INTRODUCTION ENVIRONMENTAL CONDITIONS atone wee uci rp es INITIAL CONDITIONS RECOMMENDED TEST EQUIPMENT VERIFICATION PROCEDURES DC Volts Verification TRMS AC Volts Verification Ohms Verification DC Current Verification TRMS AC Current Verification C
3. TRMS Current Calibration DISASSEMBLY INSTRUCTIONS ooo eacee o sil baba doses SPECIAL HANDLING OF STATIC SENSITIVE NS m TROUBLESHOOTING Recommended Test Equipment cm E Power Up Self Test MR res berris Diagnostics ee re oss ed Power EO RR RA or vena MR RO EN Signal Conditioning Checks darken PES Digital and Display Circuitry Checks NN ENS Scanner Checks sie aie TEE sale sw erae eo RR 222 2 teas eaea ILC 2 SCANNER INSTALLATION AND CHECKOUT PER Card Checkout RAT NINE rem rre oss EVER E edis E SECTION 7 Replaceable Parts 71 INTRODUCTION LLL i 2 m o UET Ro s M 7 2 11 Mica px MER ET aa E dou CUu 73 ORDERING INFORMATION M m AOT OPI 74 FACTORY SERVICE 75 SCHEMATIC DIAGRAMS AND COMPONENT LOCATION DRAWINGS a
4. NM 3 14 Translator Error Messages 35 Trigger to First Byte Out Times C es 3 6 Scanner Programming SECTION 4 Performance Verification 4 1 Recommended Equipment odas duce iua 4 2 Limits for DC Volts Verification sisi m em aem esee se iere remm 4 3 Limits for TRMS AC Volts Verification PON MONROE TIPS MEE ES 4 4 Limits for OHms Verification PERMET S n 4 5 Limits for DC Current TIENE 4 6 Limits for AC Current AGI Pia ipa d AE a d ades KNEE SECTION 5 Principles of Operation 5 1 Input Buffer Amplifier 046 Gain Configuration 5 8 SECTION 6 Maintenance 6 1 6 2 6 3 6 4 6 5 6 6 67 6 8 6 9 6 10 6 11 6 12 6 13 6 14 6 15 Line Voltage Selection Hcc Pr Line Fuse Replacement Current Fuse Replacement aures herbes Rete CREE EE M Recommended Calibration Equipment DC Volts Calibration Resistance Calibration ARMS AC Volts Calibration
5. Locks out local operation Returns device to default conditions Enables serial polling Disables serial polling Returns unit to default conditions Returns device to local Triggers device for reading Removes all listeners from bus Removes any talkers from bus High Programs Model 199 for various modes C 3 APPENDIX Uniline Commands The five uniline commands include REN EOI IFC ATN and SRQ Each command is associated with a dedicated bus line which is set low to assert the command in question REN Remote Enable REN is asserted by the controller to set up instruments on the bus for remote operation When REN is true devices will be removed from the local mode Depending on device configuration all front panel controls except the LOCAL button if the device is so equipped may be locked out when REN is true General ly REN should be asserted before attempting to program instruments over the bus EOI End or Identify EOI may be asserted either by the controller or by external devices to identify the last byte in a multi byte transfer sequence allowing data words of various lengths to be transmitted IFC Interface Clear IFC is asserted by the controller to clear the interface and return all devices to the talker and listener idle states ATN Attention The controller asserts ATN while sen ding addresses or multiline commands SRQ Service Request SRQ is asser
6. NEW is reserved word that tells the instrument that SETUP1 and SETUP2 are Translator words and not Keithley device dependent commands Even though the two words were combined to form SETUP3 and SETUP2 still exist as valid Translator words Wild card Translator words can also be combined with other Translator words The option number used with the new word will apply only to the first wild card word in the string For example assume that FILTER emulating the P command and FUNCTION emulating the F com mand are wild card Translator words that are to be com bined with the normal Translator word SETUP1 The for mat might look like this ALIAS TEST NEW SETUP1 NEW FUNCTION NEW FILTER The new Translator word is TEST Whenever TEST is sent the option value sent with that word will only affect func tion since FUNCTION is the first wild card command in the string For example TEST might be sent over the bus in the following format TEST 3 The 3 in the command string will ony affect the FUNC TION command In this example the instrument will be placed in the DCA function F3 Since the FILTER com mand does not have an assigned option value due to its position in the string it will default to 0 disable Programming Example The following sequence will create two Translator words and then combine them to form a third Translator word REMOTE 726 OUTPUT ALIAS SETHPiF1x OU
7. Ne c IM SEE DISPLAY BOARD SCHEMATIC 0199 116 NOTE INSTALL JUMPER TO CONNECT DIGITAL AND IEEE COMMON TO EARTH GROUND CUSTOMER INSTALLED 1 7400417 COUNTS BACK PAG UNREGULATED P16 STROBE P16 9 H I TIT E i COUNTS BACK 0 REAR Lus se SCHEMATIC DIGITAL ADARD Figure 7 4 Digital Board Schematic Diagram Dwg No 199 106 TABLE 7 3 ANALOG BOARD PARTS LIST CIRCUIT KEITHLEY DESIG DESCRIPTION PART NO ANALOG SHIELD UPPER 199 312 FUSE CARRIER FH 25 FUSE HOLDER FH 21 HEAT SINK HS 25 ANALOG SHIELD LOWER B199 313 PUSHBUTTON BROWN FOR 51 C29465 2 PUSHBUTTON RED FOR S2 C29465 3 1 IC DUAL CMR HIGH SPEED OPTO HCPL 2631 588 AT2 IC OPTOCOUPLER 2601 1C 239 IC OPTOCOUPLER 11 117 362 C15 C17 C14 C2 C22 027 CAP 1uF 20 50V CERAMIC C 365 1 6 61 66 9 d C31 CAP 150pF 5 100V CERAMIC C 372 150P C32 CAP 0047uF 10 100V POLYPROPYLENE 306 0047 C33 C56 C58 CAP 10uF 20 10096 25V ALUM ELEC C 314 10 C35 CAP 33pF 1096 1000V CERAMIC C 64 33P C38 680 5 500 138 680 C40 CAP 1uF 1096 630V POLYESTER C 364 1 C44 CAP 15uF 10 20V TANTALUM 204 15 C45 CAP 2uF 10 100V POLYESTER 294 2 C46 CAP 47uF
8. nunciators and walk through the various display segments and complete displays to verify that all are operating properly Following the test the instrument will scroll to the next program 2 7 7 Debug The debug program is intended to switch various LEDs relays and logic levels to allow signal tracing through the instrument during troubleshooting Also memory tests are performed For complete details on using the debug refer to paragraph 673 To exit the diagnostic program press any key except TRIGGER 2 7 8 Reset The reset program restores instrument setup parameters to the factory default conditions listed in Tables 2 1 and 37 Perform the following steps to use this program 1 Press SHIFT DMM SETUP and then NEXT repeatedly until the following message is displayed RESET NO 2 Use uprange or downrange to toggle the display as follows RESET YES 3 Press NEXT to reset the instrument which will return to the default conditions listed in Table 2 1 NOTES 1 The reset program can be aborted by pressing NEXT with the RESET NO message displayed 2 Once the instrument has been reset to default condi tions use save setup to save that configuration if you desire that the instrument power up in those conditions 3 The reset program has no effect on the programmed IEEE 488 primary address or line frequency setting 2 8 FRONT PANEL TRIGGERING The following paragraphs discuss front panel
9. usque eue Low level Measurement Considerations Using the Scanner with Other Instrumentation Scanner Delay diy Vek cad Rd M eR UNDA Cm Using Filtering with the Scanner Minimum Scan Interval Times SECTION 3 IEEE 488 Programming 3 1 3 2 3 3 34 3 5 3 6 3 6 1 3 6 2 3 7 373 37 2 3 8 381 38 2 38 3 384 3 8 5 INTRODUCTION ete ae A SHORECUT TO IEEE 488 OPERATION eate d e PUPA eu diede sae Rees BUS CONNECTIONS rmm INTERFACE FUNCTION 5 m ous ote PRIMARY ADDRESS SELECTION mar mamma CONTROLLER PROGRAMMING en dU RR Re cua x V ada dade Ria aU BASIC Interface Programming Statements FRONT PANEL ASPECTS OF IEEE 488 GENERAL BUS COMMAND PROGRAMMING Controller Handler Software Front Panel Error Messages TEEE 488 REMOTE Indicator and LOCAL Key diserti da AL A Ent ee citu REN Remote Enable RENT
10. 1 UNCAL 1 NO SCANNER Of 0 12 TRANSERRIO 0 1 CHAN 4 t a CHAN CAL LOCKED 1 TRANSERRIT 1 CONFLICT 1 TRANSERAIG 1 TRANSERR 9 1 TRANSERA 5 1 1a 4 1 ALWAYS ZERO 1 2000 U2 Returns Translator word list U3 Returns data store size SZE 000 04 Returns present value programmed with command in floating point U5 Returns INPUT switch status 0 front 1 rear SRO MASK AND STATUS BYTE FORMAT Bit Position 1 ROS 1 Reading Overflow SRO 199 Status Byte only 1 Error 1 Ready 1 Data Store Full 1 Data Store Half Full 1 Reading Done TRANSLATOR Translator Words and Characters Travislator Word or Character Description ALIAS Defines Translator words gt Terminates definition string 5 Wildcard definition character NEW Enabled Translator OLD Disables Translator SAVE Saves Translator words as power up default LIST Returns list of Translator words FORGET Purges Translator words from memory Table Of Contents SECTION 1 General Information 14 INTRODUCTION PP 1 2 FEATURES 13 WARRANTY INFORMATION 14 MANUAL ADDENDA D 4 E a E E EE Ee 1 5 SAFE
11. Continuous on X T5 One shot on X T6 Continuous on External Trigger T7 One shot on External Trigger The trigger modes are paired according to the type of stimulus that is used to trigger the instrument In the and modes triggering is performed by addressing the Model 199 to talk In the T2 and T3 modes the IEEE 488 multiline GET command performs the trigger function The instrument execute X character provides the trigger stimulus in the T4 and T5 modes External trigger pulses provide the trigger stimulus in the T6 and T7 modes Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition NOTES 1 The front panel TRIGGER button can be used to trig ger readings See paragraph 2 8 for details 2 In T6 the unit provides its own trigger Programming Example Place the instrument in the one shot on talk mode with the following program 18 REMOTE 726 SQ OUTPUT 726 7 TLRS ENTER 726 38 AF zB EMI In this example the ENTER statement addresses the Model 199 to talk at which point a single reading is triggered When the reading has been processed it is sent out over the bus to the computer which then displays the result 3 18 488 PROGRAMMING 3 9 8 Reading Mode The reading mode command parameters allow the selec tion of the source of data that is transmitted over the IEEE 4
12. IEEE 488 PROGRAMMING Table 3 8 Device Dependent Command Summary Cont Description Paragraph graph Value V nn nnnn or Calibration value zero value 3 9 10 Vn moe Calibrate third point using value V Data Format Reading with prefix 3 9 12 Reading without prefix Reading and buffer location with prefix Reading and buffer location without prefix Reading and channel with prefix Reading and channel without prefix Reading buffer location and channel with prefix SRQ Disable Reading overflow Data store full Data store half full Reading done Ready Error mmand To Default interval 175msec SELECT OFF 3 9 9 Qn n interval in milliseconds I5msec to 999999msec Calibration Calibrate first point using value V 3 910 Calibrate second point using value V Default Conditions Restore factory default conditions and save L1 3 9 11 u Save present machine states as default conditions Reading buffer location and channel without prefix EOI and Bus Hold off Enable EOI and bus hold off on X 3 9 14 Disable EOI enable bus hold off on X Enable EOI disable bus hold off on X Disable both EOI and bus hold off on X Terminator LF CR CR LF Status Send machine status word Send error conditions Send Translator word list Send buffer size Send current value of V Send input switch status front reax Auto Cal multiplex disabled 3 9 17 mz mee Auto Cal mul
13. V6 SECTION 1 General Information 1 1 INTRODUCTION The Keithley Model 199 System DMM Scanner is a five function autoranging digital multimeter At 54 digit resolu tion the LED display can display 302 999 counts The range of this analog to digital A D converter is greater than the normal 199 999 A D converter used in many 5 digit DMMs The built in IEEE 488 inter face makes the instrument fully programmable over the 488 bus The Model 199 can make the following basic measurements 1 DC voltage measurements from 14V to 300V 2 Resistance measurements from 110 to 300 0 3 TRMS voltage measurements from 14V to 300V 4 DC current measurements from 100nA to 5 TRMS AC current measurements from 100nA to In addition to the above mentioned measurement capabilities the Model 199 can make AC dB voltage and current measurements 1 2 FEATURES Some important Model 199 features include 10 Character Alphanumeric Display Easy to read 14 segment LEDs used for readings and front panel messages Zero Used to cancel offsets or establish baselines Data Store Can store up to 500 readings and is access ible over the bus or from the front panel Digital Calibration The instrument may be digitally calibrated from either the front panel or over the bus User Programmable Default Conditions Any instru ment measurement configuration can be es
14. 57msec 57msec 105 55msec 104 15 106msec 406msec 105msec 158msec 102 107msec 58msec 105msec 1i2msec 100msec 8 85sec DCV 185 20MQ 106msec Note Hold off occurs on X or lt CR gt lt LF gt when enabled 3 9 15 Terminator Y The terminator sequence that marks the end of the instru ment s data string or status word can be programmed by sending the Y command followed by an appropriate number The default terminator sequence is the commonly used carriage return line feed CR LF sequence Y0 The terminator will assume this default value upon power up or after the instrument receives a DCL or SDC command Programmable terminators include YO CR LF Yl LF CR Y2 HP 85 Programming Example To reserve the default CR LF terminator sequence type the following lines into the computer REMOTE Fee OUTPUT Fees When the second statement is executed the normal ter minator sequence will be reserved the instrument will ter minate each data string or status word with a CR LF 3 9 16 Status U The status command allows access to information concern ing various operating modes and conditions of the Model 199 Status commands include U0 Send machine status word 01 Send error conditions U2 List Translator words U3 Send a value indicating the buffer size U4 Send the present value V U5 Send input switch status front rear
15. IKSTRIMENTS INC 1 ALL PUSHBUTTONS SHITCHES ARE SHOWN IN THE 10 9 Pia 14 14 CLOCH 50 DATA TLEVELANO GHIA 44139 PUSHBUTTON POSITION DIGITAL COMHON 2 CENOTES DIGITAL COMMON SCHEMATIC DISPLAY BOARD D DENOTES FRONT PANEL CONTROL eco pisPLAY fisie el ue 8 gt 6 S 4 3 2 1 Figure 7 2 Display Board Schematic Diagram Dwg 199 116 TABLE 7 2 DIGITAL BOARD PARTS LIST CIRCUIT KEITHLEY DESIG DESCRIPTION PART No IEEE MOUNTING HARDWARE CS 713 C1 C3 C6 C8 C10 01uF 20 50V CERAMIC C 365 01 C14 C16 C11 CAP 22uF 20 100 25V ALUM ELEC 6314 25 C12 C13 CAP 15pF 1096 200V CERAMIC C 406 15P C2 C9 CAP 1uF 2096 50V CERAMIC 365 1 CR1 CR6 DIODE SILICON 1N4148 00 35 RF 28 J14 CONN DUAL 13 PIN BERG CS 389 3 J15 CONN MALE 3PIN 7 CS 288 3 J29 CONN STRAIGHT POST HEADER 3 PIN CS 533 3 J7 CONN RIGHT ANGLE 24 PIN CS 501 P16 CONN FEMALE 8 PIN BTM MNT CS 618 8 81 82 RES 100 5 1 4W COMPOSITION OR FILM R 76 100 R10 R11 RES NET 82 5 25W TF 141 R3 RES 38 3K 1 1 8W METAL FILM R 88 38 3K R4 RES 909K 1 1 8W METAL FILM R 88 909K R5 RES 9 09K 1 1 8W METAL FILM R 88 9 09K R6 RES 1M 596 1 4W COMPOSITION OR FILM R 76 1M R7 RES NET 3 3K 596 1 25W TF 140 R8 RES NET 3 3K 2 6W TF 101 U1 10 INPUT AND OR INVERT ARRAY PAL10L8 IC 579 U10 IC 8 BIT MICROPROCESSING UNIT 68B
16. 5 5 best 9 v hw b e ore tlt tn i SECTION 5 Principles of Operation 5 1 52 5 9 5 3 1 5 3 2 5 3 3 5 34 54 5 5 5 6 561 5 6 2 57 58 58 1 582 CONTROL CIRCUITRY POWER SUPPLIES VIA E MINA INTRODUCTION iiras eee A ESSET Oe ete OVERALL FUNCTIONAL DESCRIPTION ANALOG CIRCUITRY Input Signal Conditioning Multiplexer Reference Sout scenes seer ER ERE T E E ERE ee Input Buffer Amplifier E Cr PEE m iaa AID CONVERTER LIP DIGITAL CIRCUITRY Display Circuitry he Control Circuitry na 562465252221 Switching Relays La qid car SECTION 6 Maintenance 6 1 6 2 6 3 6 3 1 6 3 2 64 64 1 64 2 643 644 64 5 6 4 6 647 64 8 64 9 6 4 10 641 6412 6 5 6 6 6 7 6 7 1 6 7 2 6 7 3 6 74 6 7 5 6 7
17. das dua 6 4 Two Wire Resistance Calibration Conti 527 Vetus 65 Flowchart of AC Volts Calibration Procedure 6 6 TRMS AC Volts Calibration Configuration 6 7 TRMS AC Volts High Frequency Calibration Adjustments 30V and 300V Ranges 6 8 DC Current Calibration Im sisia kosis 6 9 AC Current Calibration Configuration 610 Model 199 Exploded View P 6 11 Connector PC obe id 16 16 612 Scanner Installation Ter tas ees 6 13 Scanner Connector Location rr UNIES eee ed 2 SECTION 7 Replaceable Parts APPENDIX C IEEE 488 BUS OVERVIEW Bus Configuration oe cree C2 IEEE Handshake Sequence RARE ee ener niei 3 Command Codes rr EE NE c List Of Tables SECTION 2 Basic DMM Operation 21 Factory Default 4 2 2 2 22 2 2 2 ___________ _____ ames rm 2 6 2 3 Resistance em 2 4 Corresponding Vo
18. 5 Run the program and select the desired range based the maximum expected output voltages 6 The instrument will perform the tests and display the gain values on the computer CRT after all seven amplifiers have been tested 3 44 IEEE 488 PROGRAMMING PROGRAM COMMENTS 28 OUTPUT Recall default setup 28 OUTPUT 72 amp Fixt Select ACV function 48 OUTPUT ud O Continuous GET trigger mode PRINT 81 Select range TH PRIHT 352 361 PRIHT 4 SOU SELECT 115 IMPLUT Input range 128 5 eR taka 56 tt Program 199 range 158 OUTPUT FZS zX 2 pole ratio mode 148 OUTPUT Step channel 8 limit 158 OUTPUT z amp SRQ on data store full 158 OUTPUT 726 Gaga 2 Scan interval is one second 178 OUTPUT 726 185 Store size 8 turn on store 138 PRINT PRESS UNIS Ta BEGIH Pause to make sure is ready ign PAUSE PRINT 5 SCAMHING e 218 TRIGGER 726 Trigger scan 228 STATUS 7 198 Get bus status SEG IF BITS ee 228 Wait for SRQ on store full 248 S SPOLL 72e Serial poll to SRQ 250 OUTPUT i Reading no prefix data format OUTPUT 726 E10 Readings from data store 278 ENTER Get channel 1 reading FOR 2708 Get gain
19. Apple II equipped with the Apple II IEEE 488 Interface Hewlett Packard Model 85 Hewlett Packard Series 200 and 300 Hewlett Packard Model 9825A DEC LSI 11 8 OR AT NATIONAL INSTRUMENTS GPIB PC INTERFACE The following program sends a command string from an IBM PC or AT computer and dispiays the instrument reading string on the computer CRT The computer must be equipped with the National Instruments GPIB PC IEEE 488 interface and the DOS 2 0 or 3 0 operating system The GPIB PC software must be installed and configured as described in the instruction manual DIRECTIONS 1 From the front panel set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the IEEE 488 interface installed in the IBM computer 3 BASICA on the computer keyboard to get into the IBM interpretive BASIC language 4 Place the interface software disk in the default drive type and press the return key 5 the lines below to the declaration file also modify the address in lines 1 and 2 as described in the GPIB PC instruction manual Run the program and type in the desired command string For example to place the instru ment in the ACV function and autorange type in FIROX and press the return key 7 The instrument reading string wil then appear on the computer screen A typical example is NACV 0 00000
20. Programming Example Io verify LLO operation enter the following statements REMOTE LOCAL L CEGLIT 7 After the second statement is executed the LOCAL key will be locked out To cancel LLO type in the following statement LOCAL When END LINE is pressed control to the front panel will be restored 3 8 4 GTL Go To Local The command is used to take the instrument out of the remote mode and restore operation of the front panel keys To send GIL the controller must perform the following sequence 1 Set ATN true 2 Address the Model 199 to listen 3 Place the GTL command byte on the data lines The GTL command will not cancel LLO local ica since it does not set REN false Programming Example Place the instrument in the remote mode with the following statement REMOTE 725 Verify that the instrument is in remote Send GTL as follows LOCAL 2 Note that the instrument goes into the local mode and that operation of the front panel keys has now been restored 3 8 5 DCL Device Clear The DCL command may be used to clear the Model 199 and return it to its default conditions Note that the DCL command is not an addressed command so all in struments equipped to implement DCL will do so simultaneously When the Model 199 receives a DCL com mand it will return to default conditions see paragraph 3 9 11 Table 3 7 lists factory default conditions Table 3 7 Factory De
21. 30 9msec 34 1msec 30 9msec 34 1msec 30 9msec 34 7msec 25 1msec 27 9msec 30 9msec 34 1msec 59 2msec 66 2msec 58 8msec 64 9msec 58 8msec 65 8msec 59 2msec 62 5msec 97 msec 13 msec 96 2msec 109 8msec 96 2msec 111 4msec 97 109 8msec 112 2msec 125 msec 353 5msec 362 5msec 353 5msec 362 5msec 3M 58 imsec 63 7msec 30M 278msec 31 8msec 300M 278msec 30 9msec AO off 90 4 50Hz operation Al mux on 51 5 Internal filter off mode IEEE 488 PROGRAMMING Table 3 16 Scanner Programming Commands Description Mode Command Scanner Setup Pole Ratio Ee Delay 00 s g All channels open 2 pole Step mode Stop scan all channels open 2 Pole Limit 8 CHAN 8 MAX ERROR Stop all channels open 2 Pole Limit Os Gt CO 2 pole 4 pole 2 pole ratio 4 pole ratio 4 MAX ERROR CHAN 4 MAX ERROR CHAN 4 MAX ERROR CHAN 4 MAX ERROR 4 Pole Limit 1 2 3 4 CHAN 4 MAX ERROR CHAN 4 MAX ERROR CHAN 4 MAX ERROR CHAN 4 MAX ERROR CHAN 4 MAX ERROR 4 Pole Limit 1 2 3 4 CHAN 4 MAX ERROR 4 MAX ERROR CHAN 4 MAX ERROR CHAN 4 MAX ERROR Defa lt 175msec interval SELECT OFF n interval in msec 15 999999msec n delay in msec 05 999999 Delay to be used as channel settling time 3 37 EEE 488 PROGRAMM
22. 5 The instrument reading SES will then appear on the CRE displsy is NACV 4 0 000000E 0 PROGRAM 22222 5 18 DIM 251 1251 Dimension strings 28 REMOTE 726 2 Place 199 in remote DISF COMMAND STRIHG Prompt for command 49 input command string SB OUTPUT 726 AF Address 199 to listen send string ENTER 726 Address 199 to talk input reading DISE Bf Display reading string GOTO za 2 Repeat NOTE For conversion to numeric variable change line 70 as follows 78 DISP B 5 APPENDIX B HEWLETT PACKARD SERIES 200 and 300 The following program sends commhafid string to the Model 199 from a Hewlett Packard Series 200 or 300 computer and displays the instrument reading string on the computer CRT The com puter must be equipped with the HPIB Interface and BASIC 2 0 30 or 40 DIRECTIONS 1 From the front panel set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the HPIB interface installed in the computer 3 Enter the computer EDIT mode 4 Enter the lines in the program below using the ENTER key after each line 5 Run the program and type in the desired command string at the command prompt For exam ple to place the instrument in ACV and autorange type in FIROX and press the ENTER key 6 The instrument reading will then appear on the CRT
23. Figure 5 3 Resistance Measurement Simplified Circuitry PRINCIPLES OPERATION 5 3 2 Multiplexer The multiplexer circuitry selects among the various signals that are part of the Model 199 measurement cycle and con nects them to the input buffer amplifier Figure 5 4 shows a simplified schematic of the multiplexer circuitry The Front Rear INPUT switch detector U25B is not part of a measurement cycle xS Signal 300mVDC 3VDC Sense HI 0228 U25A Signal ACV ACA Signal DCA 0258 Front Rear Switch U25C 2 8V Reference z 4250 Zero Except 52 0240 59 0246 U24B 69 U22A Zero 30V Ref LO 3000 Ref LO 30kQ Q Sense LO Q Ref LO 300k 300MQ Signal 1 Ref HI Figure 5 5 shows the general switching phases for the various signals During each phase an integration is per formed by the A D converter and the resultant data is used by the microprocessor to calculate the final reading To Input Buffer Amplifier Figure 5 4 JFET Multiplexer 5 6 PRINCIPLES OF OPERATION 2 Sense LO Phase 2 Ret HI Phase Q Ref LO Phase Reference Phase Calculate a Reading Calculate a Reading A Typical Voltage and B Typical Resistance Measurements Current Measurements Figure 5 5 Multiplexer Phases PRINCIPLES OF OPERATION 5 3 3 2 8V Reference So
24. J16 P16 To Analog Board Figure 6 11 Connector Locations 6 16 MAINTENANCE 6 6 SPECIAL HANDLING OF STATIC SENSITIVE DEVICES CMOS devices operate at very high impedance levels for low power consumption As a result any static charge that builds up on your person or clothing may be sufficient to destroy these devices if they are not handled properly CAUTION in order to avoid possible damage assume that all devices are static sensitive When handling these devices use the following precau tions to avoid damaging them _ a 1 The devices listed in the replaceable parts list should be transported and handled only in containers specially designed to prevent static build up Typically these parts will be received in anti static containers of plastic or foam Keep these devices in their original containers un til ready for installation Remove the devices from their protective containers only at a properly grounded work station Also ground yourself with a suitable wrist strap Handle the devices only by the body do not touch the pins Any printed circuit board into which the devices is to be inserted must also be grounded to the bench or table Use only anti static type solder suckers Use only grounded tip solder irons m MO mally adequately protected and normal handling can resume 6 6 7 TROUBLESHOOTING The troubleshooting information contained in this secti
25. OUTPUT 726 AF 722 LOCAL ree CLEAR 725 CLEAR 7 REMOTE 7 LOCAL 2 SPOLL 47267 LOCAL LOL TRIGGER 726 ABORT 7 Send 3 7 FRONT PANEL ASPECTS OF IEEE 488 OPERATION The following paragraphs discuss aspects of the front panel that are part of IEEE 488 operation including front panel error messages IEEE 488 status indicators and the LOCAL key 3 7 1 Front Panel Error Messages The Model 199 has a number of front panel error messages associated with IEEE 488 programming These messages are intended to inform you of certain conditions that may occur when sending device dependent commands to the instrument as summarized in Table 3 5 The following paragraphs discuss each of these messages in detail Note that the instrument may be programmed to generate an SRQ paragraph 3 9 13 and the error word can be checked for specific error conditions paragraph 3 9 16 if any of these errors occur 37 488 PROGRAMMING Table 3 5 Front Panel IEEE 488 Messages Description ees NO REMOTE Instrument programmed with REN false Illegal Device dependent Command Illegal Device dependent Command Option Instrument triggered while it is still processing a previous trigger Instrument cannot store readings at programmed in terval Readings will be stored as fast as the instru ment can run Programmed display message exceeds 10 characters Calibration command sent with cali
26. PAGE 1 20NE AS PAGE S PAGE 5 ZONE C1 gt CLOCK LONG 500 ZAC ATTEN z IVAC RELAY lt SCANNER RELAY pase AY 3u REL RELAY PAGE NE SENSE KE PAGE 26 40 2 1 PAGE 4 20NE 83 PAGE 1 ZONE 83 NOT INSTALLED i 4 xis PAGE 3 20NE B RESIS DR 3 ZAG 1 Z0NE 18 lt 1 20NE 219 PAGE 1 20NE 2 2 gt SENSE LO 1 20NE PAGE 1 20ME B2 RCR nae lt 2 20NE i 00 1 ZONE 9 T HUX RTTEN 100K SENSE 1M 30mA C 1 zone 1 20NE lt 1 20NE 1 20NE PAGE 1 20NE lease 2 20NE 100K X 1 20NE DHM PAGE 1 20NE lt B4 c PAGE 4 ZORE SENSE Al 1 rere SCHEMATIC ANRLOG BOARD 199 126 soos Frees 1 3 OF 5 8 7 6 4 5 Figure 7 6 Analog Board Schematic Diagram Dwg No 199 126 sheet 3 of 5 A D INPUT PAGE 3 0 06 PAGE 3 PAGE 3 ZONE 01 2 NE NOT INSERTED C4 196 602 04 C 9 PAGE 3 20NE n1 196 602 652 1 INSTALLED 196 602 A D COUNTS PAGE 5 ZONE 186 602 3 20NE 01 SYNC gt PAGE 3 20NE
27. The rear panel input jacks are most convenient for this configuration NOTE Make sure the INPUT switch is set for the rear in put terminals Figure 2 12 shows typical input connections for voltage measurements Input connections for 2 wire ohms measurements are shown in Figure and 2 13 4 pole Connections Four pole connections are used exclusively for 4 wire ohms measurements With this configuration the paired chan nels 1 and 5 2 and 6 3 and 7 4 and 8 must be connected to the resistances under test as shown in the typical con nections of Figure 2 14 The two outputs are separately con nected to VOLTS OHMS and OHMS SENSE terminals us ing the supplied output cables Note that the two outputs must not be connected together in the 4 pole mode 2 25 BASIC DMM OPERATION A 2 POLE OUTPUT CONNECTIONS 8 4 POLE OUTPUT CONNECTIONS OUT A H Figure 2 11 Output Cable Connections 2 26 BASIC DMM OPERATION Voltages Under Test 1992 CARD Supplied Volts Ohms Output Rear Input Cables Figure 2 12 Voltage Test Connections 2 27 BASIC DMM OPERATION Resistors Under Test 1992 CARD To 199 Volts Ohms _ Figure 2 13 2 Pole Resistor Test Connections BASIC DMM OPERATION Resistors Under Test H 1992 CARD LO Connect All Test Leads Directly To Resistor To 199 To 199 Ohms Sense Volts Ohms Supplied Output Cables Figure 2 14 4 Pole Resist
28. print able ASCH Up to 10 characters may be sent D Restores display back to normal Notes 1 In order to have spaces preceding the begin ning of the message and between message words use the sym bol to represent each space For example to display the message Model 199 starting at the second display character one space send the following command string S SoH 2 Spaces a command string ignored 3 Sending a message that exceeds 10 characters will result in the BIG STRING error message being displayed Programming Example Enter the following statements in to the computer to display the message MODEL 199 REMOTE 738 OUTPUT 725 SS x The instrument model number will be displayed Display operation may be returned to normal by entering the following statement GUTPUT 726 05 3 10 TRANSLATOR SOFTWARE The built in Translator software allows the user to define his own words in place of Keithley s defined device dependent commands One word can replace a single command or a string of commands For example the word can be sent in place of F1 and the word SETUP can be sent in place of F3R1T2S0Z1U0M2 Also Keithley com mands can be translated to emulate functions of other units For example the word RA which is used by H P to select autorange can be sent in place of RO There are certain words and characters that cann
29. the data store buffer is full or continuously in wra around mode 1992 CARD 2 11 SCANNER OPERATION WITH OPTION 1992 With the optional Model 1992 Scanner installed the Model 199 can scan four 4 pole channels or eight 2 pole chan nels The following paragraphs discuss scanner program ming connections and operation from the front panel Refer to paragraph 3 12 for IEEE 488 scanner programm ing For scanner installation procedures refer to Section 6 2 11 1 Scanner Connections Figure 210 shows the Model 1992 Scanner Card and its two quick disconnect terminal blocks To remove each block from the card simply pull on the attached handle until it comes free of the card Screw terminals on the blocks accept up to 14AWG solid or stranded wire 0006000000 Pull as Shown to Figure 2 10 Scanner Connections 2 24 BASIC DMM OPERATION Terminal configurations are marked on the circuit board and connecting blocks Channel input terminals are mark ed CHI through CH8 inclusive Each channel input has a HI and LO terminal labelled H and L respectively Two sets of output terminals OUT A and OUT B are also located on the connecting blocks The output configura tion depends on the whether 2 pole or 4 pole mode is to be used as discussed below WARNING Maximum common mode voltage potential between any contact and earth ground is 350V peak Exceeding this value may create a shock hazard WARNING User
30. will allow any valid option number of the F command 0 through 6 to be sent with the word The second statement which is the substitute for the Fl command will place the instrument in the ACV function The third statement is a substitute for the F2 command and will place the instru ment in the ohms function 3 32 Trying to define a Translator word that already exists The second string in the example is the Use of FORGET in a Translator definition Display E Message Explanation Example Error String TRANSERR 9 No more memory left for Translator words Use of more than one ALIAS in a definition ALIAS TESTI FIX ALIAS TEST2 Rix ALIAS ITHINKTHISISTHIRTYTWOCHARACT ERS FIX ALIAS XRAY FIX ALIAS SETUP FIX ALIAS SETUP RIX ALIAS 200 FIX ALIAS DOG LIST ALIAS DOG FIX FORGET ALIAS DOG FIX SAVE NOTES 1 When sending a wild card Translator word over the bus there must be a space between the Translator word and the option number 2 If a wild card Translator word is sent without an option number the instrument will default to option 0 Programming Example Enter the following program to define a wild card Translator word to emulate the P filter command REMOTE 25 OUTPUT ALIAS FILTER DUTPUT 726 7 FILTER 2 The second statement defines FILTER as the wild card Translator word for the P command
31. 2 3 7 Input Terminals P ee oe 2 4 REAR PANEL FAMILIARIZATION X Se ace een aioe cee cere eee uM 241 Connectors and Terminals ee n s 24 2 Line Voltage Aspects eid Roc dap eli Rowe 243 TEEE 488 Connector 244 Scanner Card Slot 4 act e e e I E 2 5 DISPLAY MESSAGES SERRE MEE DR 2 6 BASIC 5 ded 2 61 Warm Up Period POP 262 Zero Hc m E T ea 2 6 3 Filter and Resolution NP 2 64 DC Voltage Measurements dT Vail mre ebur rrr e 2 6 5 Low Level Measurement Considerations m MIC cc iode 2 6 6 Resistance Measurements 2 ide Dre 2 67 TRMS AC Voltage Measurements gia Ra pda ad fa ugue edu 268 Current Measurements DC or TRMS 2 6 9 dB Measurements eee eee eee ce munere diae edenda crm cie 2 6 10 TRMS
32. APPENDIX A ASCII CHARACTER CODES AND IEEE 488 MULTILINE INTERFACE COMMAND MESSAGES APPENDIX CONTROLLER 5 APPENDIX IEEE 488 BUS OVERVIEW rea nal ate ee PA vivi List Of Illustrations SECTION 2 Basic DMM Operation 2 1 Model 199 Front 2 2 Model 199 Rear Panel EE 2 3 DC Voltage Measurements ee ee re mn 2 4 Two erminal Resistance 2 5 Four lerminal Resistance Measurements 2 6 TRMS AC Voltage Measurement 27 Current Measurements 2 8 External Trigger Pulse Specifications cT 2 9 Meter Complete Pulse 5 cee odes eee aie 2 10 Scanner 5 PON 21 Output Cable Connections pA OT PESE 212 Voltage Test Connections rere ac C p RP MTM 2 13 2 Pole Resistor Test 2
33. Data Data Data Data Management Handshake Handshake Handshake Management Management Management Ground Data Data Data Data Management Ground Ground Ground Ground Ground Ground Ground Contact Number 488 Designation DIO1 DIO2 DIO3 DIO4 EOI 24 DAV NRFD NDAC 1 2 3 4 5 6 7 8 9 10 1 12 13 4 5 16 7 18 19 20 21 22 Gnd LOGIC Numbers in parentheses refer to signal ground return of referenced contact number EOI and REN signal lines return on contact 24 3 4 INTERFACE FUNCTION CODES The interface function codes which are part of the IEEE 488 standards define an instrument s ability to sup port various interface functions and they should not be confused with programming commands found elsewhere in this manual Interface function codes fox the Model 199 are listed in Table 3 3 and are listed for convenience on the rear panel adjacent to the IEEE 488 connector The codes define Model 199 capabilities as follows SH Source Handshake SH1 defines the ability of the Model 199 to properly handshake data or command bytes when the unit is acting as a source Acceptor Handshake A H1 defines the ability of the Model 199 to properly handshake the bus when it is ac ting as an acceptor of data or commands IEEE 488 PROGRAMMING Talker The ability of the Model 199 to send data over the bus to other devices is defined by the T function
34. Figure 7 5 Analog Board Component Location Drawing Dwg 199 120 NOTE DO NOT INSERT C4 C10 41 C42 C43 54 55 C77 C78 W1 09 34 56 amp C37 ACU INPUT SEN oirr vv SENSE HI e PAGE 2 20NE 08 PAGE 3 20 3 2 600 4 1 RELAY ES SIG g 1339 PAGE 3 20NE C1 PAGE 3 20NE Di 12 100K Q 10UR PAGE 1 20NE Ce 15U 159 5 2 race 2 20NE ni OHH RELAY EMEN PAGE 3 SWITCH ZONE PAGE 2 P ME 1 gt 4 130 154 2 600 PAGE 3 20NE ues PAGE 2 20NE 01 BMS PAGE 3 12 AL C OHM SENSE MI m 5 PAGE 3 20NE 81 3 ZAC 15 gt 50 LM339 VOLTS OHMS HI PAGE 1 VOLTS OHMS LO NOT Ugo INSERTED 99 PAGE 3 gy SHITCH SENSE LO ZONE hi READ SWITCH gt PAGE 3 0NE Bi PAGE 3 B6 REF gt Lc 100K SENSE PAGE 3 20NE 01 15U 159 L2 9 PAGE 3 PAGE 3 RONE At ZONE Bi 4 OHMS SENSE HI LK 4 90 VOLTS OHMS HI P EDT M 16 DHMS SENSE LU ZZERO PAGE 3 Z0NE D1 z lt lt AMPS CURRENT INPUT PAGE 2 20NE BH YOLTS OHM 0 PAGE 3 20NE 1 IMPUT LO PAGE 2 80HE AB INPUT BUFFER PAGE 3 20NE 08 gt 18U 159 ZSENSE LO a lt KEXTHLEY INSTRUMEHTS INC PAGE 5 PASE 3 gt
35. Proceed as follows in order to check or set the line frequency 1 Press SHIFT DMM SETUP and then NEXT repeatedly until the line frequency message is displayed For 60Hz the display will show fe FREQ 60Hz 2 For 50Hz the display message is FREQ 50Hz 3 Use uprange or downrange to toggle to the desired fre quency then press NEXT to go on to the next program NOTES 1 To change the default frequency setting first select the desired frequency and then use the save setup program or send L1 over the bus to save the new frequency set ting Cycling power or sending SDC DCL or LO over the bus will not affect the programmed line frequency If the line frequency is changed but not saved with the save setup program sending SDC or DCL over the bus will return the line frequency to the default setting However the reset program will not have any effect on the current frequency setting and sending LO over the bus will not change the setting but will save the new frequency An UNCAL error will default the 488 primary address to 26 and set the line frequency to 60Hz N 45 2 7 5 Setup The save setup program allows you to save current instru ment conditions These conditions will then be assumed upon power up or after the instrument receives the DCL or SDC command over the IEEE 488 bus The following operating parameters are saved by this program Function Range Resolut
36. REMOTE 26 OUTPUT 726 3 17 IEEE 488 PROGRAMMING The filter will turn on 3 9 6 Rate S The rate command controls the integration period and the usable resolution of the Model 199 Table 3 10 lists the usable resolution on each function for the two S modes The integration period is dependent on usable resolution as shown in Table 3 10 Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition Programming Example From the front panel set the display of the Model 199 for at 44 resolution Now enter the following statements into the computer REMOTE OUTPUT TZET SINN When END LINE is pressed the second time the 51 rate will be selected 5 digit resolution Table 3 10 Rate Command Summary Integration si Command Resolution Period 54 50 51 2 59msec Line 20msec 50Hz 16 67msec 60Hz 3 9 7 Trigger Mode T Triggering provides a stimulus to begin a reading conver sion within the instrument Triggering may be done in two basic ways in a continuous mode a single trigger com mand is used to start a continuous series of readings in a one shot trigger mode a separate trigger stimulus is re quired to start each conversion The Model 199 has eight trigger commands as follows TO Continuous on Talk T1 One shot on Talk T2 Continuous on GET T3 One shot on GET
37. Reading Overflow 1 Data Store Full 1 Data Store Half Full 1 Reading Done Figure 3 7 SRQ Mask and Serial Poll Byte Format Table 3 11 Command Parameters Condition to Generate SRQ Disable Reading overflow Data store full Data store half full Reading done Ready Error The bits in the serial poll byte have the following meanings Bit 0 Reading Overflow Set when an overrange input is applied to the instrument Cleared when the input is on range Bit 1 Data Store Set when the defined data store size is full Cleared by re enabling data store Bit 2 Data Store Full Set when half the defined data store size is full Cleared by re enabling data store Bit 3 Reading Done Set when the instrument has com pleted the present reading conversion Cleared while pro cessing a reading Bit 4 Ready Set when the instrument has processed all previously received commands and is ready to accept ad ditional commands over the bus Cleared while the instru ment is processing commands Bit 5 Error Set when one of the following errors has occurred Trigger Overrun Interval Overrun Big String Uncalibrated Cal Locked Conflict No Remote IDDC IDDCO 10 Translator 11 No Scanner 12 Chan 4 Maximum 13 Channel 8 Maximum ON DOP ON PP The error bit is cleared by reading the U1 word The nature of the error can be determined with the U1 command as explained in paragra
38. SELECTION TG 174 SELECTION TG 139 TRANS N CHANNEL MOSPOWER FET 2N7000 TRANS N CHANNEL JFET PN5434 SELECTION TG 128 TRANS N CHANNEL FET SELECTION TG 138 RES 1M 5925 1 4W COMPOSITION OR FILM RES 100K 1 1W METAL FILM RES NET 10M 1 111M 110 95K 10 101K RES NET 100K 2 2 25W RES 100K 1 1 8BW METAL FILM RES 30K 1 1 8W RES 13K 1 1 10W METAL FILM RES 1M 1 1 8W METAL FILM RES 2K 1 1 8W RES 1 002K 1 1 10W METAL FILM RES 1K 5 1 4W COMPOSITION OR FILM RES 1 196 7 5W WIRE WOUND RES 22M 10 1 2W FIXED COMPOSITION RES 118K 1 1 10W METAL RES 1 17M 25 75W METAL FILM RES 20K 5 6 5W WIRE WOUND RES 9 09K 1 1 10W METAL FILM RES 32 4K 1 1 8W METAL FILM RES 20K 196 1 10W METAL FILM RES 1 1 8W METAL FILM RES 15 8K 1 1 8W METAL FILM RES 7 87K 1 1 8W METAL FILM RES 142 8K 1 1 8W RES 560K 576 1 4W COMPOSITION OR FILM RES 18 2K 195 1 8W METAL FILM RES 8 25K 195 1 8W METAL FILM HES 2K 576 1 4W COMPOSITION OR FILM RES 1K 196 1 8W METAL FILM RES 1 33K 196 1 10W METAL FILM RES 11K 195 1 10W METAL FILM RES MATCHED SET HES 996K 195 1 4W METAL FILM RES 6 19K 1 1 10W METAL FILM RES 9K 196 1 8W METAL FILM RES 15K 1 1 8W METAL FILM RES 14K 1 1 8BW METAL FILM RES 10 525 1 8W METAL FILM RES 12 4K 1 1 8W METAL FILM RES 9 76K 196 1 8W METAL FILM RES 220 5 1 4W COMPOSITION FILM RES 7 78K 1 1 8W RES 162K 195 1 8W METAL FILM RES 7 5K 5 1 4W COMPOSITION OR FIL
39. The ratio mode divides the channel 2 through 8 readings by the channel 1 reading as follows R CHI Where R ratio CHn channel 2 through 8 CH1 CH 1 The ratio mode is available for all three scan modes discussed below While in ratio the instrument displays the selected function for channel 1 and the actual ratios without units for channels 2 through 8 Ratio can be enabled or disabled by using the SCAN SETUP key as follows 1 Press SHIFT SCAN SETUP and then NEXT twice to display the current ratio status With ratio disabled the display is RATIO OFF 2 For ratio enabled the display shows RATIO ON 3 To change the ratio status press uprange or downrange 4 Once the desired ratio status is displayed press NEXT once to advance to the next selection or press NEXT twice to return to normal display NOTES 1 In the MANUAL mode you must manually access Channel 1 first before attempting to display the ratio on Channels 2 through 8 2 The ratio is automatically scaled if the range is chang ed after the channel 1 reading is taken in order to main tain a constant ratio reference value across ranges For example if you take a 10V channel 1 reading on the 30V reading the ratio reference will remain 10V on the 300V range 3 Setting the range lower than the channel 1 ratio reference reading will cause an overflow 4 The minimum ratio display value is equal to the display resolution The maximu
40. When the command sequence is transmitted the in strument will transmit the status word instead of its nor mal data string the next time it is addressed to talk The status word will be transmitted only once each time the U0 command is given To make sure that correct status is transmitted the status word should be requested as soon as possible after the command is transmitted The format of UO status is shown in Figure 3 8 Note that the letters correspond to modes programmed by the respective device dependent commands The default values in the status word are also shown in Figure 3 8 Note that all returned values correspond to the programmed numeric values For example if the instrument is present ly in the R3 range the second R byte in the status word will correspond to an ASCII 3 The U1 command allows access to Model 199 error condi tions in a similar manner Once the sequence U1X is sent the instrument will transmit the error conditions with the format shown in Figure 3 9 the next time it is addressed to talk in the normal manner The error condition word will be sent only once each time the U1 command is transmitted Note that the error condition word is actual ly a string of ASCH characters representing binary bit posi tions An error condition is also flagged in the serial poll byte and the instrument can be programmed to generate an SRQ when an error condition occurs See paragraph 3 9 13 Note that all
41. 11 through 24 01 pins 6 and 16 U2 pins 4 7 14 17 US pins 3 4 5 6 10 11 and 12 U4 pins 1 3 4 5 PM pin 7 50 5V 590 Variable pulses Variable pulses msec pin 5 S1 PM pin 3 52 button Step Htem Component _________ Required Condition imsec negative going pulse every Depress 51 52 53 54 button Depress 55 56 57 or 58 button Depress S9 510 571 512 or 513 5V supply Segment drivers Digit drivers Pulse present when button pressed Pulse present when button pressed Pulse present when button pressed Table 6 15 Scanner Board Checks Step Item Component pins 2 and 4 5V 5 5 then goes LO U2 pin 2 6 8 SCANNER INSTALLATION AND CHECKOUT The following paragraphs discuss installation of the Model 1992 Scanner and Scanner checkout procedures Refer to paragraph 2 11 for front panel scanner operation IEEE 488 control of the scanner is located in paragraph 3 12 6 8 1 installation Using Figure 6 12 and 6 13 install the Model 1992 Scanner as discussed below Required Condition Remarks Stays high second on power up Negative going pulses Positive going pulses Positive going pulses On relay output LO all others HI Contact resistance 500mtQ signals referenced to analog ground P1 pins 1 and 2 Power on safe guard Control
42. 2 For use with card memory address other than C400 modify the DEF SEG statement in line 10 accordingly For example with a card memory address of C000 line 10 should be modified as follows i8 DEF yov donde 3 In order for Translator to function properly a lt CR sequence should be added to the end of any string sent to the Model 199 See the example is line 65 above B 3 APPENDIX B 4 APPLE APPLE il JEEE 488 INTERFACE The following program sends a command string to the Model 199 from an Apple computer and displays the instrument reading string on the computer CRT The computer must be equipped with the Apple H IEEE 488 Interface installed in slot 3 DIRECTIONS 1 From the front panel set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the IEEE 488 interface installed in the Apple computer 3 Enter the lines in the program below using the RETURN key after each line 4 Run the program and type in the desired command string at the command prompt For exam ple to place the instrument in ACV and autorange type in FiROX and press the return key 5 The instrument reading string will then appear on the CRT A typical display is NACV 0 00000E 0 PROGRAM UNT COMMENTS _ 18 2 CHRS 263 Terminator zB INFOT COMMAND STRING 77 BS Prompt for and enter command string Set output to IEEE 488 bus 48 1485 D
43. 44 2C e 3 MLA 12 45 2D Dem MLA 13 46 MLA 14 47 2F MLA 15 48 30 0 MLA 16 49 31 1 MLA 17 50 32 2 MLA 18 51 33 3 MLA 19 52 34 4 MLA 20 53 35 5 MLA 21 54 36 MLA 22 55 37 7 MLA 23 56 38 8 o an MLA 24 57 39 9 MLA 25 58 3A MLA 26 59 3B z 27 60 lt MLA 28 61 3D 29 62 gt 30 63 2 UNL Message sent or received with ATN true Numbers shown represent primary address resulting in MLA My Listen Address Model 199 default listen address 2 APPENDIX ASCII CHARACTER CODES AND IEEE 488 MULTILINE INTERFACE COMMAND MESSAGES Decimal Hexadecimal ASCH TEEE 488 Messages 64 40 MTA 0 65 41 A MIA 1 66 42 B MTA 2 67 43 3 68 44 D MTA 4 69 45 E 5 70 46 MIA 6 71 47 G 7 72 48 H MTA 8 73 49 I MTA 9 74 4A J MTA 10 75 4B K 11 76 4C X MTA 12 77 4D M MTA 13 78 4E N MTA 14 79 4F 15 80 50 P 16 81 51 Q 17 82 52 R MTA 18 83 53 5 19 84 54 T MTA 20 85 55 U MTA 21 86 56 M 22 87 57 23 88 58 24 89 59 MTA 25 90 5A Z 26 91 5 27 92 5C 28 93 50 29 94 SE n MTA 30 95 oF UNT Message sent or received with ATN true Numbers shown are primary address resulting in MTA My Talk Address Model 199 default talk address
44. 44 PRIHT 3 21 IEEE 488 PROGRAMMING 6 1 2 Digits Buffer Location G2 G3 G6 G7 Bs G4 G5 G6 G7 NDCV 1 T E 1 B400 i LF Normal Overflow 2 Zeroed DCV DC Volts ACV AC Volts OHM Ohms DC Amps AC Amps dBV AC dB Volts AC dB Amps RAT Ratio Exponent Notes p n EA Channel Prefix Buffer Prefix 1 Buffer Location 8000 with Data Store Disabled 2 Channel CO with no Scanner or Scanner Disabled Figure 3 6 General Data Format When the second statement is executed the instrument will change to the G1 mode The last two statements quire data from the instrument and display the reading string on the CRT Note that no prefix or suffix appears on the data string 3 9 13 SRQ Mask M and Serial Poll Byte Format The SRQ command controls which of a number of condi tions within the Model 199 will cause the instrument to request service from the controller by asserting an SRQ Once an SRQ is generated that serial poll byte can be checked to determine if the Model 199 was the instrument that asserted the SRQ and if so what conditions can be Checked by using the U1 command as described in paragraph 3 9 13 The Model 199 can be programmed to generate an SRQ under one or more of the following conditions 1 When a reading is completed or an overrange condition occurs 2 a bus error occurs 3 When
45. D p30 D 5 OUTPUT LO J2 j kerta ey EN SCHEMATIC RELAY CARD SIZEIMODEL eco 1992 1992 106 13880 DRM APPROVED bare 5 e 1 Figure 7 8 Model 1992 Schematic Diagram Dwg 1992 106 APPENDIX ASCII CHARACTER CODES AND IEEE 488 MULTILINE INTERFACE COMMAND MESSAGES Decimal Hexadecimal ASCII TEEE 488 Messages 0 00 NUL 1 01 SOH GTL 2 02 STX 3 03 ETX 4 04 SDC 5 065 6 06 ACK 7 07 BEL 8 08 BS 7 9 09 HT TCT 10 0A LF 08 13 OD CR 0 50 15 OF SI 16 10 DLE 7 11 DCI LLO 18 12 DC2 19 B DC3 20 14 DC4 Gain Hs DCL 21 15 PPU 22 16 SYN 23 7 24 18 SPE 25 19 SPD 26 1A SUB 27 28 1 ee 29 1D GS 30 1E RS 31 ne Message sent or received with true APPENDIX _ 5 lt ASCII CHARACTER CODES AND 488 MULTILINE INTERFACE COMMAND MESSAGES Decimal Hexadecimal ASCH 488 Messages 32 20 SP 25 MLA 0 33 21 1 34 22 MLA 2 35 23 MEM MLA 3 36 24 MLA 4 37 25 MLA 5 38 26 amp MLA 6 39 27 MLA 7 40 28 MLA 8 41 29 MLA 9 42 2A vi MLA 10 43 2B MLA 11
46. Erase Sa ANE DC Current Calibration DA 5 AC Current Calibration ERE RUPEE M RU Recommended Troubleshooting oem Model 199 Troubleshooting m TP Sas Power Supply Checks Digital Circuitry Checks POT ee Display Circuitry Checks Scanner Board Checks 44 4 4 42 0 LP 2 48 44 4 44 4 ee amp 5 APPENDIX C IEEE 488 BUS OVERVIEW C2 4 5 IEEE 488 Bus Command m Hexadecimal and Decimal Command Codes n Typical Addressed Command Sequence Uum Typical Device Dependent Command Sequence Command Group o6 A 9 1 b mh A 9 v m Vom 4 9 v A 4
47. Q3 U22C U24C 012 Q3 U22C U24C Q12 Q3 U22C U24C Q12 U22C U24C 0666 6666 lt SENSE LO REF HI REF LO SENSE HI 012 013 022 U24C 012 Q13 22 U24C 012 013 U22C U24C QD 013 U22C U24C 4 SENSE LO REF HI SENSE HI No Test QD U22C U24C U24B Q32 Q2 U22C U24C Q35 QD U22C U24C Q30 56 K2 Q12 U22C U24C U24B 032 REF HI 012 U22C U24C Q35 SENSE Hi Q12 U22C U24C Q30 No Test SIG ZERO U23C U25D Q32 CAL ZERO U23C o U25D Q32 CAL U23C U25C Q32 SIG U23C 0228 Q32 SIG ZERO 026 036 037 0250 932 CAL ZERO Q26 036 037 0250 032 CAL 026 Q36 037 25 032 SIG 26 36 Q37 U22B 032 ZERO U23D U23B U23C U25D 032 CAL U23D U23B U23C 25 032 SIG E U23D U23B U23C U22C Q32 No Test ZERO Q26 036 037 U23C U23D U23B U25D Q32 CAL 026 036 037 U23C U23D U23B U25C 032 SIG Q26 036 037 U23C U23D U23B U22C 032 No Test aes 6 20 MAINTENANCE Table 6 12 Power Supply Checks Required Condition _ 53 Line Switch Set to 115 or 230V as required Line voltage selection F2 Line Fuse Check for continuity Remove fuse to check Line Power Plugged into live receptacle power on 5V Digital Supply 053 pin 3 5V 5 Referenced to digital common 5V Analog Supply 51 pin 3 5V 5 Reference to analog common 15V Analog Supplies U52 pi
48. QUAD COMP LM339 SELECTION iC 325 IC CMOS ANALOG SWITCH DG211 18 OP AMP LF353N IC TRMS TO DC CONVERTER 637JD IC DUAL JFET INPUT OP AMP LF412 IC 8 STAGE SHIFT STR REGIST MC14094BCP IC DARLINGTON TRANS ARRAY ULN20003A IC QUAD 2 INPUT OR GATES 74HC02 IC TRIP 2 CHAN MULTIPL DEMUX CD4053BC SELECTION IC 165 IC HEX INVERTER 74HCTO4 IC NEG VOLTAGE REG 15V 500mA 79M15 VOLTAGE REGULATOR 7805 C POS VOLTAGE REG 15V 500mA 78M15 HEAT SINK ASS Y IC QUAD 2 INPUT 74 00 IC DUAL D TYPE FLIP FLOP 74HC74 DIODE ZENER 4 3V 1N5991B DIODE ZENER 6 4V 1N4579 CRYSTAL 3 84MHz 8 76 470 R 76 10K R 76 100K TF 39 R 76 200 R 88 1 18K RT 9 2 SW 468 SW 466 SW 476 TR 259 TR 258 TE 97 1 1G 540 31847 1 500 462 219 196 601 320 246 IC 352 C 504 251 1C 206 IC 412 283 A30167 444 195 1 93 194 A32469 4 IC 351 337 DZ 81 DZ 73 CR 13 pave 12552 E 12911 ARTWORK HAS REU D N H E sz 27197661 SETS RUA 58 2 16 90 G 14653 ARTHORK FROM REV TO 6 52 8 6 91 H 14922 cn 15087 20 anYwork Rey H Toa dd 2 29 92 10 lor LO 640 5 Lo 5 5266 55 Q6 05
49. Range RO Auto Auto Auto Auto R1 300mV 300mV 30mA 30mA 300 9 Auto Auto R2 3 Auto Auto R3 30V 30V 3 A 30kQ Auto Auto R4 300 V 300 V 300kQ Auto Auto R5 300 V 30 Auto Auto R6 300 V 30M2 R7 300 V V 300MQ ACA Ohms dB ACA dB 3 3 488 PROGRAMMING 3 3 BUS CONNECTIONS The Model 199 is intended to be connected to the IEEE 488 bus through a cable equipped with standard IEEE 488 con nectors an example of which is shown in Figure 3 2 The connector is designed to be stacked to allow a number of parallel connections at one instrument Two screws are located on each connector to ensure that connections re main secure Current standards call for metric threads which are identified with dark colored screws Earlier ver sions had different screws which were silver colored Do not attempt to use these type of connectors on the Model 199 which is designed for metric threads Figure 3 2 IEEE 488 Connector A typical connecting scheme for a multiple instrument test set up is shown in Figure 3 3 Although any number of connectors can be stacked on one instrument it is recom mended that you stack no more than three connectors on any one unit to avoid possible mechanical damage 3 4 Instrument instrument Instrument Controller Figure 3 3 IEEE 488 Connections Connect the Model 199 to the IEE
50. The third statement enables the front panel filter FLTR on IEEE 488 PROGRAMMING 3 10 3 NEW and OLD NEW is a reserved word that tells the instrument that the ensuing commands may be defined Translator words The instrument will then respond to the Translator words as well as Keithley device dependent commands The re served word ALIAS automatically places the instrument in the NEW mode NEW is also used to combine Translator words and is explained in paragraph 3 104 OLD is a reserved word that prevents the instrument from responding to the defined Translator words In this mode only the Keithley device dependent commands will be recognized over the bus Programming Example Enter the following statements in to the computer to place the instrument in the NEW mode REMOTE Tee GUTPUT 726 The instrument will go into the NEW mode 3 10 4 Combining Translator Words Existing Translator words can be combined resulting in Translator word that contains the commands of the two or more combined words For example existing Translator words SETUP1 and SETUP2 can be combined and named SETUP3 When SETUP3 is sent over the bus the commands of both SETUP1 and SETUP2 will be executed The format for combining Translator words is shown in the following example ALIAS SETUP3 NEW SETUP1 NEW SETUP2 Where _ SETUP3 is the new Translator word SETUP1 and SETUP2 are words to be
51. Type in the desired command string and press the RETURN key For example to program the instrument for ACV and autorange type in FIROX and press RETURN Tl The instrument data string will appear on the computer display A typical display is NACV 0 000000E 0 PROGRAM IEEE 2 LOGICALe1 1 1 8 CALL IESTERCI amp gt CONT IHUE CALL 15 5 CALL 1287 CALL IETERMC CALL 4 TYFE amp FORMAT 1X EHTER ADDRESS 24 gt ACCEPT PRIADE FORMAT Iz3 TYPE 15 FORMAT Las TEST SETIF CALL MEG CALL 1 PEIBIE INPUT 1 1 CALL PUTSTRE INPUT 58 CALL IEUHT GOTO ie e me CA roo m Repeat COMMENTS Turn off IB errors Allow 5 error 155 Allow 1 second bus timeout Set line feed as terminator Turn on remote Input primary address Prompt for command string Program instrument Address 199 to listen send string Get data from instrument Untalk the 199 APPENDIX IEEE 488 BUS OVERVIEW BUS DESCRIPTION The IEEE 488 bus which is also frequently referred to as the GPIB General Purpose Interface Bus was designed as a parallel transfer medium to optimize data transfer wi
52. at one time Although several active listeners may be pre sent simultaneously only one active talker may be present on the bus or communications would be scrambled TO OTHER DEVICES DATA BUS DATA BYTE TRANSFER CONTROL ONLY ABLE TO LISTEN PRINTER GENERAL INTERFACE MANAGEMENT D 101 8 DATA BLINES DAV HANDSHAKE NOAG SRQ BUS REN MANAGEMENT Figure C 1 IEEE Bus Configuration APPENDIX A device is placed in the talk or listen mode from the con troller by sending an appropriate talk or listen command These talk and listen commands are derived from an in strument s primary address The primary address may have any value between 0 and 30 and is generally set by rear panel switches or programmed in from the front panel as in the case of the Model 199 The actual listen com mand value sent over the bus is derived by ORing the primary address with 20 the symbol preceding the number designates a hexadecimal or base 16 value For example if the primary address is 26 the default Model 199 value the actual listen command byte value is SLA 20 3A In a similar manner the talk command byte is derived by ORing the primary address with 40 With a primary address of 26 the actual talk command byte would be 4A 40 The IEEE 488 standards also include another addressing mode called secondary
53. frequen of 20Hz and verify that the reading is within the limits listed in Table 4 6 4 Repeat the 30mA measurement at the other frequencies specified in Table 4 6 5 Repeat the procedure for the 3A range by applying the AC current level listed in Table 4 6 Check to see that the reading is within the limits listed in the table Shielded E Cable Current AC Voltage Calibrator Calibrator Model 2500E Model 5200A H shielded Cable Figure 4 6 Connections for TRMS AC Current Verification Tabie 4 6 Limits for AC Current Verification Il 199 Applied Allowable Readings 18 C to 28 C Range AC Current 208 45Hz 28 29 5900 28 du 28 2 29 1840 29 m 2 88160 2 88160 to to 2 91840 2 91840 4 5 4 6 5 Principles of Operation 5 1 INTRODUCTION This section contains an overall functional description of the Model 199 Detailed schematics and component loca tion drawings are located at the end of this instruction manual 5 2 OVERALL FUNCTIONAL DESCRIPTION A simplified block diagram of the Model 199 is shown in Figure 5 1 The instrument may be divided into two sec tions analog and digital circuitry The analog and digital sections are electrically isolated from each other by the use of opto isolators for control and communications Separate power supplies for the analog and digital sections ensure prope
54. listed in Table 7 5 7 3 ORDERING INFORMATION To place an order or to obtain information concerning replacement parts contact your Keithley representative or the factory See inside front cover for addresses When ordering include the following information 1 Instrument Model Number Replaceable Parts 2 instrument Serial Number 3 Parts Description 4 Circuit Designation if applicable 5 Keithley Part Number If an additional instruction manual is required order the manual package Keithley Part Number 199 901 00 The manual package contains an instruction manual and any applicable addenda 7 4 FACTORY SERVICE If the instrument is to be returned to the factory for ser vice please complete the service form which follows this section and return it with the instrument 7 5 SCHEMATIC DIAGRAMS AND COMPONENT LOCATION DRAWINGS Schematic diagrams and component location drawings follow the appropriate replaceable parts list for that par ticular board 71 TABLE 7 1 DISPLAY BOARD PARTS LIST CIRCUIT DESIG DS1 DS5 DS6 DS10 0812 0814 0816 0817 14 51 54 56 57 59 511 513 51 513 55 58 01 02 04 05 DESCRIPTION CAP 1 UF 20 50V CERAMIC DISPLAY DIGITAL DOUBLE DIGIT PILOT LIGHT RED LED MOUNTING KIT FOR PL 71 S CABLE ASSEMBLY 26 CONDUCTOR PUSHBUTTON CAPS SWITGH MOMENTARY _ PUSHBUTTON CAPS IC SINK DRIVER UND2596A 1C 8 BIT PAR OUT SHIFT REG 74HCT164 KEITHLEY PART
55. the desired value is displayed press SHIFT to program the value Alternate Condition Selection Most DMM setup pro grams have alternate conditions that can be selected To toggle the conditions press uprange or downrange to alter nate between the the two selections Exiting DMM Setup To exit DMM setups repeatedly press NEXT and scroll through the complete list in the menu Table 2 6 DMM Setup Programs Display Message Program Description Upon Ent Software revision level REV A0 66 Multiplexer on off MUX ON IEEE Primary Address 26 TEEE Line frequency 50 60Hz FREQ 60Hz Save instrument setups SAVE NO LED Test LEDS OFF Diagnostics DEBUG OFF Reset instrument RESET NO Factory default values shown 60Hz is default in the U S only Revision level may vary 2 16 BASIC DMM OPERATION 2 7 1 Software Revision Level Upon entry to the DMM setup programs the instrument will briefly display the software revision level presently in stalled in the unit as in the example below REV A0 66 2 7 2 Multiplexer Auto Zero Cal The multiplexer auto cal routines may be defeated by selec ting this option under DMM setups Using the Model 199 with auto zero cal defeated has two main advantages 1 increased measurement speed and 2 reduced multi plexer effects on high impedance measurements NOTE With the multiplexer disabled internal calibration and z
56. 01 PAGE 3 BONE C4 NOT 1234 B UNUSED GATES 15 3 XNC RUNE Di KEXTHLEY nemecurs SCHEMATIC ANALOG MODEL T D es 199 126 pate SHT 4 OF 5 PAGE 3 2 Dt Figure 7 6 Analog Board Schematic Diagram Dwg No 199 126 sheet 4 of 5 5000 ISOLATION Sap i BU UNREGULATED 2 e IN SHEET 3 LINE DEPENDENT ONES REGISTER SHEET 3 CONTROL ZONE DS INPUTS MATES WITH PL SEE DIGITAL SCHEMATIC 0199 106 SHEET 3 Z HE 05 3 16 90 125 1710A 1480 2500 8 0 COUNTS SHEET 4 ZONE CL 446 89 UNREGULATED HIN LINE DEPENDENT 16 50 L 71 COMMON i KEITHLEY gees me SCHEMATIC ANALOG BOARD POWER SUPPLY AND OPTOISOLATORS Figure 7 6 Analog Board Schematic Diagram Dwg No 199 126 sheet 5 of 5 TABLE 7 4 MISCELLANEOUS PARTS LIST KEITHLEY DESCRIPTION BANANA JACK BANANA JACK BANANA JACK BNC CONNECTOR CAPACITOR CONNECTOR CONNECTOR HOUSING COVER FASTENER FRONT FOOT ASSEMBLY FRONT PANEL FRONT PANEL OVERLAY LINE CORD LUG MODIFIED CROSS EXTRUSION MODIFIED SIDE EXTRUSION PEM STUD REAR BEZEL REAR FOOT REAR PANEL SCANNER COVER PLATE WINDOW PART NO BJ 12 0 BJ 12 2 BJ 12 9 765 520 64 1000 CS 627 CS 287 3 D199 308 FA 206 1 706 317 D199 30
57. 01 dB 11 DC VOLTS 5 Digits OHMS 512 Digits ACCURACY rdg counts RESO RANGE LUTION 30 1 0 NOMINAL 24 Hours 90 Days 1 Year SHORT 23 1 18 28 C 18 28 17mA 0 005 48 0 009 4 0 012 43 3 02 10 ma 17 mA 0 004 2 0 008 3 0 009 30 100 mf 160 A 0 04 2 0 008 3 0 009 300 1550 50 pA 0 014 2 0 024 3 0 026 10 2 5 pA 00 2 003 3 0 03 30 10 Q2 0 5 01 5 012 5 0 12 300 MQ 1 05 20 45 20 5 20 4 2 digit accuracy count error is 5 except 15 3000 range 4 wire accuracy 3000 3000 ranges properly zeroed Relative tc calibration standards CONFIGURATION Automatic 2 or 4 wire MAXIMUM ALLOWABLE INPUT 300V rms or 425V peak whichever is less OPEN CIRCUIT VOLTAGE lt 5 5V DC AMPS 51 Digits ACCURACY MAXIMUM ordg counts VOLTAGE RANGE RESOLUTION 1 Year 182 250 BURDEN 04 2 N 30 mA 100 nA 0 05 15 10 91 15 For 412 416 accuracy count error is 20 MAXIMUM ALLOWABLE INPUT 34 Protected with 3A 250V fuse accessible from front panel TRMS AMPS 5 Digits mH ACCURACY counts RESO 1 Year 189 269 RANGE LUTION 20 45 Hz 45 Hz 10 kHz 30mA 100 2 100 0 6 100 3A 10 2 100 0 6 100 Inputs gt 2000 counts For 4 digit accuracy divide count error by 10 4 5 digit specifications apply for input
58. 2095 50V POLYESTER C 350 47 C47 1uF 20 50V POLYESTER C 350 1 C48 VAR CAP 2 5 6pF 500V C 359 C49 CAP 7 75pF 500V VARIABLE C 484 C53 CAP 68pF 5 500V POLYSTYRENE C 138 68P C59 CAP 1500uF 20 100 25V ALUM ELEC C 314 1500 C60 CAP 47uF 20 100 25V ALUM ELEC C 314 47 C63 C65 CAP 680uF 10 100 35V ELECTROLYTIC C 309 680 C72 CAP 10 000uF 20 30 25V ALUM ELEC C 342 10 000 C73 C75 C76 CAP 22pF 10926 1000V CERAMIC C 64 22P C74 CAP 820pF 10 1000V CERAMIC C 64 820P CR1 CR3 CR12 CR16 DIODE DIFFUSED 1N4148 RF 28 CR13 CR14 DIODE SILICON WO4M RF 46 CR15 DIODE BRIDGE KBP02 RF 36 CH6 DIODE BRIDGE PEOS RF 48 CR7 DIODE SILICON 1N4139 RF 34 GR8 GR11 DIODE SWITCHING 1N4149 RF 60 F1 FUSE 3A 250V FU 82 F2 FUSE 3 16A 250V 3AG SLO BLO FU 29 J16 CONN MALE 8 PIN 5 338 13 17 25 CONN BRASS PIN TE 110 J26 CONN DUAL 5 PIN BERG 5 389 4 46 RECEPTACLE 5 388 K1 K2 RELAY SPST HIGH VOLTAGE RL 99 K3 K5 RELAY SPST HIGH VOLTAGE RL 70 Q1 Q22 Q26 Q36 Q30 Q33 Q35 Q37 Q5 Q6 Q12 Q32 034 7 08 011 013 017 Q16 R1 R2 R45 R52 R12 R15 R17 R20 R21 R23 R24 R25 R26 R27 R3 R30 R31 R32 R33 R34 R35 R54 R55 R56 R57 R58 R59 R6 R60 R61 R62 R63 R64 R66 R67 R68 18 6K R69 15K R7 R70 R71 R72 R73 R75 R76 R77 R79 R8 R80 R81 R82 R85 R83 R84 R86 TRANS N CHANNEL DUAL 841 TRANS NPN TRANS GES5818 TRANS N CHANNEL FET BUZ71
59. 6 Check the 3V 30V and 300V ranges by applying the respective DC voltage levels listed in Table 4 2 Verify to see that the reading for each range is within the limits listed in the table 7 Repeat the procedure for each of the ranges with negative voltages Table 4 2 Limits for DC Volts Verification 199 Applied Allowable Readings DCV Range DC Voltage 18 to 28 C 299 961 to 300 039 2 99977 to 3 00023 29 9970 to 30 0030 299 970 to 300 030 NOTE Repeat procedure for negative voltages DC Voltage Calibrator Model 5440A MODEL 199 Figure 4 1 Connections for DC Volts Verification 4 5 2 TRMS AC Volts Verification With the instrument set to 5124 resolution perform the following procedure to verify the AC volts function CAUTION Do not exceed 300V RMS 425V peak 10 V Hz between the input and LO terminals or instru ment damage may occur 1 Select the ACV function and autorange Do not use zero to cancel the offset in this procedure Turn zero off if it is enabled 2 Connect the AC calibrator to the Model 199 as shown in Figure 4 2 3 Set the calibrator to output 290mV at a frequency of 20Hz and verify that the reading is within the limits listed in Table 4 3 4 Repeat the 290mV measurement at the other frequen 465 specified in Table 4 3 5 Repeat the procedure for the 3V 30V and 300V ranges by applying the respective AC voltages listed in Table 4 3 Check t see that the re
60. ALWAYS ZERO 1 TRANSERR21 1 TRANSERR20 is TRANSERR19 1 TRANSERR18 12 TRANSERR17 12 TRANSERR16 1 TRANSERRH15 i12 TRANSERR14 ALWAYS ZERO 1 Figure 3 9 U1 Error Status Word The various bits in the error condition word are des cribed as follows TRIGGER OVERRUN Set when the instrument receives a trigger while it is still processing a reading from a previous trigger INTERVAL OVERRUN Set when the instrument cannot run as fast as the selected interval BIG STRING Set if more than a 10 Character message is sent using the display D command UNCAL Set when memory fails the self test Instrument calibration is invalid NO SCANNERC Set if a scanner command is sent with no scanner installed CHAN 4 if attempting to program channels 5 through 8 in the 4 pole mode CHAN 8 MAX Set if scanner commands 9 or N19 are sent CAL LOCKED Set when trying to calibrate the instru ment with the calibration switch in the disable position CONFLICT Set when trying to calibrate the instrument while it is in an improper state i e dB function Translator Error TRANSERR Set when any one of ten possible Translator errors occur Table 3 15 in paragraph 3 10 lists and describes the Translator errors NO REMOTE Set when a progamming command is received when REN is false IDDC Set when an illegal device dependent command such as EI
61. AMPS function NOTE For front panel calibration omit step 4 of the following procedure For IEEE 488 bus calibration omitstep3 1 Select the AC AMPS function and the 30mA range 2 Connect the AC current calibrator to the instrument as shown in Figure 6 9 3 For front panel calibration press SHIFT LOCAL and proceed as follows MAINTENANCE A With the 30 0000mA AC calibration point displayed Table 6 9 TRMS AC Current Calibration on the Model 199 set the current calibrator to out put 30 0000 at a frequency of 500Hz B After waiting sufficient time for the measurement to Current settle press the NEXT button The following 199 Calibrator message will be displayed for several seconds Calibration Output TEEE 488 Point 500Hz Bus Commands WORKING oye 30 0000mA 30 0000mA V30E 3XCOX C With the 03 0000mA AC calibration point displayed 03 0000 0 set the current calibrator to output 03 0000mA 3 00000 3000 00mA 500 2 0 30000 0300 00mA V300E 3XCIX D After allowing the measurement to settle press the NEXT button The following mae will be displayed for several seconds WORKING E The instrument will exit the calibration program and return to the 30mA range Repeat the procedures in step 3 for the AC range MODEL 199 using Table 6 9 as a guide For IEEE 488 bus calibration proceed as follows Set the current calibrator to output 30 0000mA at LO I
62. CLOCK Control DATA Control STROBE Close selected channel using SCANNER button Check HI and LO for each relay close relay with SCANNER button WARNING Disconnect the line cord and all test leads from the Model 199 before removing the case cover 1 Remove the two screws that secure the rear bezel then remove the bezel 2 Remove the screws that secure the case cover to the case sides then slide the cover off the instrument to the rear 3 Remove the two screws that secure the cover plate to the rear panel then remove the cover plate Save the screws which will be used secure the scanner card to the rear panel MAINTENANCE WARNING The cover plate must be installed if the scan ner card is removed 4 Remove the two quick disconnect terminal blocks from the scanner card before installation 5 Orient the scanner card above its final location see Figure 6 12 and plug the ribbon cable P1 into the mating receptacle 126 on the analog board see Figure 6 13 The red mark on the ribbon cable must be oriented on the right as viewed from the front of unit 6 Put the scanner card into the unit so that it lines up with the rear panel slot and is adjacent to the grooves in the case side 7 Secure the scanner card to the rear panel with the two screws removed in step 2 8 Secure the scanner card to the analog board 1 using the supplied 6 32 x 14 8 screw WARNING The
63. DC Volts Calibration 6 6 199 DCV 199 Calibration DC Calibrator TEEE 488 Range se Point Setting Bus Command lt lt lt lt lt lt lt lt lt 300 2 V300E 3XCOX VOXCIX V 3XC2X V3XCOX VOXCIX V 30XC2X VOXCIX V 300XC2X V300XCOX VOXCIX 1 2 3 Select the ohms function and the 3000 range Connect the resistance calibrator to the instrument as shown in Figure 6 3 For front panel calibration press SHIFT LOCAL and proceed as follows A With the 190 0002 calibration displayed on the Model 199 set the resistance calibrator to 1900 After allowing sufficient time for the calibrator resistance to settle press the NEXT button The following message will be displayed for several seconds WORKING C With the 000 0002 calibration point displayed set the resistance calibrator to SHORT 00 D After waiting sufficient time for the calibrator resistance to settle press the ENTER button The following message will be displayed fro several seconds WORKING E The instrument will exit the calibration program and return to the 3000 range E Repeat the procedures i in step 3 for the remaining ohms ranges using Table 6 6 as a guide For 488 bus calibration proceed as follows A Set the resistance calibrator to 1909 B After allowing sufficient time for the resistance calibrator to settle send the following commands
64. Factory default conditions are set at the factory and are listed in Tables 3 7 and 2 1 The instrument will power up to these default conditions The current IEEE address and line frequency setting of the instrument are not affected by the LO command The L1 command is used to save the current instrument conditions The instrument will then power up to these default conditions Any of the options of the following device dependent com mands can be saved as the default conditions A multiplex F function P Filter Q and I reading in terval and size R range S rate trigger delay and Z zero The L command options are as follows LO Restore instrument to factory default conditions and save 11 L1 Save present machine states as the default conditions Programming Example Set the Model 199 to the ohms function and enable zero and filter Now enter the follow ing statements into the computer REMOTE gt 26 After the second statement cycle power on the Model 199 and note that the instrument returns to the conditions in itially set in this example IEEE 488 PROGRAMMING 3 9 12 Data Format G The G command controls the format of the data that the instrument sends over the bus Readings may be sent with or without prefixes Prefixes are the mnemonics preceding the reading and the buffer memory location Figure 3 6 further clarifies the general data format The
65. Fee gt Send U command 46 5 mdlaEFG HOP Gase S THAW Obtain UO status from instrument 8 PRINT AS Display status word T ENTER T 26 AT Get normal reading 86 PRIHT At Display normal reading EHD After entering the program run it by pressing the RUN key The machine conditions of the Model 199 will be listed on the CRT display To show that status is transmitted on ly once a normal reading is requested and displayed last 3 9 17 Auto Cal Multiplex A The Model 199 has built in multiplex routines that automatically calibrate and zero the instrument so as to maintain its high accuracy The multiplex routines can be controlled through commands below See paragraph 2 7 2 for more information AO Disable multiplex Al Enable multiplex Upon power up or after a DCL or SDC command the in strument will return to the default condition Programming Example Disable multiplex by entering the following statements into the computer REMOTE ree DUTFUT Fees When the second statement is executed the multiplexer routines will be disabled 3 9 18 Trigger Delay W The delay command controls the time interval that occurs from the point the instrument is triggered until it begins integration of the input signal This feature is useful in situations where a specific time period must transpire to allow an input signal to settle before measurem
66. INPUT 300V rms or 425V es whichever is less TRMS AC VOLTS 512 Digits ACCURACY ordg counts 1 Year 18 28 C RESO 20 Hz 50 Hz 200 Hz 20 kHz RANGE LUTION 50 200 Hz 20kHz 100 kHz 300 mV 24100 0 35 100 0 15 200 2 0 300 24100 0 35 100 0 15 200 15 300 30 V 100 pV 2 100 0 35 100 0 15 200 1 5 300 300 2 100 0 35 100 0 15 200 1 5 300 For 4 4 d git accuracy divide count error by 10 4 2 digit specifica tions apply for inputs gt 20082 Sinewave inputs gt 2000 counts Sinewave inputs gt 20 000 counts RESPONSE True root mean square ac coupled CREST FACTOR ratio of peak to rms Up to 3 1 allowable NON SINUSOIDAL INPUTS 220 000 counts For rectified sine wave add 0 3 of reading to above specifications for fundamental frequencies 20kHz For pulse waveforms add 0 396 of reading for fundamen tal frequencies lt 1kHz or 3 5 for frequencies lt 10kHz INPUT IMPEDANCE 1 shunted by lt 100pF MAXIMUM ALLOWABLE INPUT 300V rms or 425V peak 10 VeHz whichever is less gt 604 at 50Hz 60Hz 0 05 with 1kQ in either lead SETTLING TIME 1 second to within 0 1 of change in reading dB ref 1V ACCURACY dB ies RESO 1 Year 18 28 C INPUT LUTION 20 20 kHz 20 kHz 100 kHz to 49 dB 20 mV 300 V 0 01 dB 0 2 0 4 54 to 34 dB 2 mV to 20 mV 0
67. KEITHLEY Srvc 44329 ZONE Ai 42 6 SCHEMATIC ANALOG BOARD 926 199 126 lios 8 7 5 4 4 2 1 SHT 1 OF 5 Figure 7 6 Analog Board Schematic Diagram Dwg 199 126 sheet 1 of 5 gt 730098 500 PAGE Z 20NE C1 PAGE 3 0NE ACY RELAY ACY INPUT PASE 1 08 5 PAGE 3 20NE All CURRENT INPUT Bib PAGE 1 20NE INPUT N Lo PAGE 1 20NE B6 158U 159 71SU 154 NOT INSERTED Ny PAGE 3 ZONE C1 3unc RELAY 1 Lead NOT INSERTED NOT INSERTED INSERTED NOT INSERTED 15U 150 0 uel 1 B eoa PAGE 3 206 25 ATTEN g 8 17353 4 150 15u 15V PAGE 3 20NE 3URE 15U 154 gt PAGE 3 PAGE 3 20NE Bi gt 2 6U PAGE 1 C 18U 159 uez 6 4s CURRENT PAGE 1 80N amp Stevo ono aa SCHEMATIC ANALOG BOARD 0 7 e Figure 7 6 Analog Board Schematic Diagram Dwg No 199 126 sheet 2 of 5 MATES WITH P1 FAST SEE SCANNER BOARD SCHEMATIC C1992 106 J26 J26 926 9 READ SWITCH i 516 D INPUT BUFFER AEE AZO INPUT ZFINAL SLOPE lt PAGE 4 20 01 STROBE SYNE PAGE 5 20 B1 STROBE 2
68. Model 199 is usable immediately when it is first turned on However the instrument must be allowed to warm up for at least two hours to achieve rated accuracy 2 6 2 Zero The zero feature serves as a means of baseline suppres sion by allowing a stored offset value to be subtracted from subsequent readings When the ZERO button is pressed the instrument takes the currently displayed reading as a baseline value subsequent readings represent the dif ference between the applied signal level and the stored baseline A baseline level can be established for any or all measure ment functions and is remembered by each function For example a 10V baseline can be established on DCV 5 baseline can be established and a 10 baseline can be established on OHMS at the same time These levels will not be cancelled by switching back and forth between functions Once a baseline is established for a measure ment function that stored level will be the same regardless of what range the Model 199 is on For example if is established as the baseline on the 3V range then the baseline will also be on the 30V through 300V ranges A zero baseline level can be as large as full range NOTE The following discussion on dynamic range is based a display resolution of 5 digits At 442d resolution the number of counts would be re duced by a factor of 10 By design the dynamic measurement range of the Model 199 a
69. NO C 365 1 DD 39 PL 71 MK 22 3 CA 27 4 B228 317 5 SW 435 B228 317 6 10 578 C 456 REVISION ENG DATE 12596 32428 12615 22 06 CHG D ARTWORK FROM REV E TOF 4 10 92 D e 9 e 2 o000000 o000000 e 699512 18 15 690819 9 511 Sie e o o o o o 052 55 5059 0510 057 0516 0511 9 5469 5669 5369 S969 5 C O e 13 51 57 NOTE INSTALL MK 22 3 UNDER 056 THRU DS10 D812 THRU 0514 0516 0517 PUSHBUTTON SELECTION CHART Figure 7 1 Display Board Component Location Drawing Dwg No 199 110 DS1 054 NAN VAN e fe NAN VN Dic gt Lj M ix io e gt gt 19 14 12 a 16 jun 18 6 H3 Jis P14 AP14 14 AP14 1 25 20 P14 14 14 14 14 AP14 14 14 14 APA APILA a t h d n h 1 NOT INSTALL C1 Ci NOTES
70. Ohms Connect To Rear Panel Input Using Supplied Cables Figure 3 10 2 Resistor Test Connections 3 42 IEEE 488 PROGRAMMING Resistors Under Test Reference Resistor To 199 To 199 Ohms Sense Volts Ohms Figure 3 11 4 Pole Resistor Test Connections 3 43 IEEE 488 PROGRAMMING PROGRAM 26 725 ZB 726 i FZEZTEZXx 72 amp SB PRIHT 1 2 POLE PRINT 2 4 P LE MODET TU PRIHT FRIHT SELECT gt 198 lt 1 0 gt 28 118 IF 2 1 8 128 IF 2 4 128 0 0 1 145 5 H 158 Pes SO 168 OUTPUT res OUTPUT Pee st 17 120 FEIHT FRESS CDhHT BEGIN 138 PAUSE TRIGGER 210 PRINT SDCAHHIHG zz S SPOLL r261 m zin IF HOT BIT 241 THEM 228 248 52 67252 OUTPUT T2 6 i GIBIHIBS EHTER 725 RI FOR 2 H 726 FRIHT HT I 5 TOLERANCE HEXT I Qi DO f m og mt xt 3 12 6 Amplifier Gain Testing The scanner can be used to simplify gain testing of amplifiers As shown in Figure 3 12 a signal generator sup plies a test signal to the inputs of all seven amplifiers be ing tested Chan
71. SAVE LEDSON Test front panel LEDs and annunciators LEDS L LEDS OFF DEBUG YES Enter troubleshooting mode DEBUG L DEBUG NO RESET YES Returns unit to factory default configuration RESET L RESET NO ONE SHOT OPERATION In the one shot trigger mode each reading consists of multiple conver sions to fill the Running Average User Filter 30 conversions or the Run ning Average Internal Filter 5224 only varies by ranges and function see manual For this reason trigger to reading time could be several seconds depending on filtering When filters are off command over the bus can be SAVEd readings are made up of only one conversion STORE SHIFT STORE to enter data store SIZE 1 to 500 or SIZE 000 for wrap around NEXT to exit size select TRIGGER to initiate storage Any function key to cancel storage RCL flashes when data store is full RECALL SHIFI RECALL to enter recall NEXT to view data at displayed location or V to scroll through locations RECALL again to select desired location _ NEXT to display data NEXT to exit recall mode ERROR MESSAGES UNCAL EEPROM failure on power up OVERFL Overrange TRIGGER OVERRUN Unit triggered while processing reading INTERVAL OVERRUN Interval too short for selected configuration AC ONLY dB selected with unit not in ACV or ACA NO RANGE Pressing range button in dB CAL LOCKED Calibration
72. SCANNER The unit will prompt you for the channel to close CHANNEL 8 Press the desired numeric key to close that channel For example to close channel 3 press 3 9 The unit will close the selected channel and display the channel number in the right most digit 10 you have selected the one shot trigger mode press TRIGGER to trigger a reading 11 To select a different channel press SCANNER followed by the new channel number The unit will open the presently selected channel and then close the new channel break before make 12 To open all channels and return to normal operation select channel 0 press SCANNER 0 NOTES 1 When using the ratio mode you must first access chan nel 1 to obtain a ratio reference reading before access ing other channels 2 In the 4 pole mode the maximum channel number is channel 4 Selecting channels 5 through 8 will generate a CHAN 4 MAX error 2 31 BASIC DMM OPERATION 2 11 8 Step Mode Operation In the STEP mode the instrument will scan one channel per reading interval continuous trigger mode or one channel per trigger one shot trigger mode The pro cedures for setting up and using the unit are covered below Reading Interval Scanning 1 Select the function and range for the expected measure ment 2 Press SHIFT TRIG SETUP and select the continuous trigger mode using uprange or downrange 3 Press NEXT twice to display the programmed interv
73. The Model 1681 con tains two leads 1 2m 4 ft long terminated with banana plugs and spring action clip probes Model 1682A RF Probe The Model 1682A permits voltage measurements from 100kHz to 250MHz AC to DC transfer accuracy is 1dB from 100kHz to 250MHz at IV peak responding calibrated in RMS of a sine wave Model 1685 Clamp On AC Probe The Model 1685 measures AC current by clamping on to a single conduc tor Interruption of the circuit is unnecessary The Model 1685 detects currents by sensing the changing magnetic field produced by the current flow Model 1751 Safety Test Leads Finger guards and shrouded banana plugs help minimize the chance of making contact with live circuitry Model 1754 Universal Test Lead Model 1754 is 12 piece test lead kit with interchangeable plug in ac cessories Included in the kit is set of test leads 1 red 1 black two spade lugs two standard banana plugs two phone tips 0 06 DIA two hooks and miniature alligator clips with boots Model 1992 4 8 Channel Scanner The Model 1992 Scan ner option allows scanning of four 4 pole channels or eight 2 pole channels The Model 1992 installs within the Model 199 with connections available on the rear panel of the instrument Model 1993 Quick Disconnect Scanner Connector Kit The Model 1993 includes two connector blocks 10 tie wraps and two sets of red and black output cables for the Model 1992 S
74. The control sequence is essentially the same as that used for the main DMM circuitry discussed previous ly The U2 output for the relay that is to be closed is set low while the remaining outputs are high so that only one relay is closed at any given time U1 and associated components are included in order to ensure that relays do not randomly close during power up 5 10 PRINCIPLES OF OPERATION At power up the Q output of U1 goes high disabling the outputs of U2 When the first STROBE pulse comes along the D type flip flop in U1 is cleared enabling the U2 out puts and normal relay operation can commence depen ding on channel control data 5 8 2 Switching Relays Each of the eight input channels has a DPST double pole single throw relay associated with it in order to switch the and LO terminals separately The relays are connected in two four unit groups for maximum versatility in pole switching Relays Ki through K4 are associated with out put A while relays K5 through K8 are connected to out put B For 2 pole operations the user must strap the two outputs together HI to HI LO to LO while the outputs must be connected separately for 4 pole operation 5 1U5 D2 SECTION 6 Maintenance 6 1 INTRODUCTION This section contains information necessary to maintain calibrate and troubleshoot the Model 199 Fuse replace ment and line voltage selection procedures are also included WARNING The p
75. The size of the data store can be controlled by one of the following 1 commands I0 Wrap around storage mode In Set data store size to n 1 to 500 In the wrap around data storage mode 10 storage will not stop after the buffer is filled 500 readings but will proceed back to the first memory location and start over writing data With the Innn command the storage pro cess will stop when the defined number of readings have been stored In this case the buffer is considered to be full 3 19 IEEE 488 PROGRAMMING m OUTPUT 726 SS ENTER Peni 38 AF EHE 18 725 2 NOTES 1 Sending the I command enables data store however the unit must be properly triggered to begin storage once data store is enabled When the I command is sent will be displayed until the first trigger occurs The data store can be disabled by sending the command The INTERVAL OVERRUN error message indicates that the instrument cannot store readings at the programm ed interval rate Instead readings will be stored as fast as the instrument can run Either during or after the storage process readings may be recalled by using the B1 or 82 command as describ ed in the previous paragraph M Ut Upon power up or after the instrument receives a or SDC command the Model 199 will return to the default condition Programming Example E
76. The state of ATN determines how infor mation on the data lines is to be interpreted IFC Interface Clear IFC allows the clearing of active talkers or listeners from the bus REN Remote Enable REN is used to place devices in the remote mode Usually devices must be in remote before they can be programmed over the bus EOI End Or Identify EO is used to mark the end of a multi byte data transfer sequence EOI is also used along with ATN to send the IDY identify message for parallel polling SRQ Service Request SRQ is used by devices to request service from the controller Handshake Lines Three handshake lines that operate in an interlocked se quence are used to ensure reliable data transmission regardless of the transfer rate Generally data transfer will occur at a rate determined by the slowest active device on the bus These handshake lines are DAV Data Valid The source talker controls the state of DAV to indicate to any listeners when data is valid NRFD Not Ready For Data The acceptor listener con trols the state of NRFD it is used to signal the transmit ting device to hold off the byte transfer sequence until the accepting device is ready NDAC Not Data Accepted NDAC is also controlled by the accepting device The state of NDAC tells the source whether or not the device has accepted the data byte Figure C 2 shows the basic handshake sequence for the transmission of one data by
77. about the Model 199 including that necessary to inspect the instrument and get it operating as quickly as possible Section 2 contains detailed operating information on using the front panel controls and programs making connections and basic measuring techniques for each of the available measuring functions Section 3 contains the information necessary to connect the Model 199 to the IEEE 488 bus and program operating modes and functions from a controller Section 4 contains performance verification procedures for the instrument This information will be helpful if you wish to verify that the instrument is operating in compliance with its stated specifications Section 5 contains a description of operating theory Analog digital power supply and IEEE 488 interface operation is included Section 6 contains information for servicing the instru ment This section includes information on fuse replace ment line voltage selection calibration and trouble shooting Section 7 contains replaceable parts information 1 9 GETTING STARTED The Model 199 System DMM is a highly sophisticated in strument with many capabilities To get the instrument up and running quickly use the following procedure For com plete information on operating the Model 199 consult the appropriate Section of this manual Power Up 1 Plug the line cord into the rear panel power jack and plug the other end of the cord into an appropriate groun
78. and display it on the computer CRT 18 REMOTE 726 28 OUTPUT Pees ZH EHTER 736 AF At 24 EHI The second statement above sets the instrument to the A D converter reading mode The third and fourth statements acquire the reading and display it on the 3 9 9 Data Store Interval Q and Size 1 The data store is controlled by the interval command Q and the size command Interval With the Q command the user can select the interval that the instrument will store readings The Q command is in the following form Q0 175msec default interval SELECT OFF Qn Set interval in millisec I5msec to 999999msec Note that the programmed interval also affects the inter _ val between readings and scan interval To store readings at a selected interval Qn the instru ment must be in a continuous trigger mode TU T2 T4 T6 When the selected trigger occurs the storage process will commence One Shot Trigger Into Data Store To use the data store in the one shot mode the instrument must be in a one shot trigger mode 11 T3 T5 or T7 In the Tl mode one reading will be stored each time the in strument is addressed to talk In the T3 mode each GET command will cause one reading to be stored In the T5 mode each instrument execute character X will cause a reading to be stored Finally in the 17 mode each exter nal trigger pulse will cause a reading to be stored Size
79. be 30 0000 even though only the first two digits were actually sent Digital Calibration When performing digital calibration two three for DCV points must be calibrated on each range The first calibration value should be approximately full range and the second calibration value should be ap proximately zero The third point is at minus full range for DCV only After the second or third calibration value is sent over the bus permanent storage of the two values will occur P In order to send calibration values over the bus the calibra tion command C must be sent after the value command V is sent The calibration command takes on the follow ing form C0 Calibrate first point using value V Cl Calibrate second point using value V 2 third point using value The following example first sends a calibration value of 3 and then a calibration of 0 VOXCIX If the calibration value is greater than 303000 counts at 5124 resolution an IDDCO error message will be on the Model 199 CAUTION Precision calibration signals must be connected to the instrument before attempting calibration otherwise instrument accuracy will be affected See Section 6 for complete details on cali brating the instrument either from the front panel or over the bus 3 9 11 Default Conditions L The L0 command allows the user to return the instrument to the factory default conditions
80. energy circuit when set to a current range low resistance range or any other low impedance range the circuit is virtually shorted Dangerous arcing can also result when the meter is set to voltage range if the minimum voltage spac ing is reduced When making measurements in high energy circuits use test leads that meet the following requirements Test leads should be fully insulated Only use test leads that be connected to the circuit e g alligator clips spade lugs etc for hands off measurements Do not use test leads that decrease voltage spacing This diminishes arc protection and creates a hazardous condition Use the following sequence when testing power circuits 1 De energize the circuit using the regular installed connect disconnect device such as the circuit breaker main switch etc 2 Attach the test leads to the circuit under test Use propriate safety rated leads for this application 3 Set the DMM to the proper function and range 4 Energize the circuit using the installed connect disconnect device and make measurements without disconnecting the DMM 5 De energize the circuit using the installed connect disconnect device 6 Disconnect the test leads from the circuit under test CAUTION The maximum common mode input voltage the voltage between input LO and chassis ground is 500V peak Exceeding this value may damage the instrument 2 6 1 Warm Up Period _ The
81. exit the recall mode by pressing NEXT while scanned data is displayed Although the Model 199 does not display the scan se quence number you can easily determine which sequence is being displayed by noting the data store location number location number can be displayed by pressing RECALL while in the recall mode For example if eight channels were scanned locations 1 through 8 would store channels 1 through 8 data for the first sequence locations 9 through 16 would store channels 1 through 8 data from the second sequence and so on 2 11 11 Practical Scanner Application Amplifier Testing The Model 199 equipped with the Model 1992 can perform tests on amplifiers with minimal external equipment The following paragraphs discuss two such amplifier tests gain and bandwidth testing Amplifier Gain The ratio mode used in conjunction with the scanner can be used to determine the gain of seven different amplifier using the test configuration shown in Figure 2 15 A signal generator is also necessary to supply the test signal to the inputs of the amplifiers which are also connected to the channel 1 input of the scanner Note that the outputs of the amplifiers are connected to the channels 2 through 8 inputs of the scanner Because the maximum ratio the Model 199 can display is 10 amplifier gains are limited to that value For higher gains the values must be computed manually BASIC DMM OPERATION Signal Gene
82. instru ment in autoranging which is available for all ranges and functions While in autoranging the unit will go to the best range to measure the ap plied signal Autoranging can be cancelled by press ing AUTO or one of the two manual ranging but tons discussed below DMM allows ac cess to the following functions software revision level multiplexer on off IEEE 488 primary address programming 50 60Hz line frequency selection save setup LED test debug and instrument reset see paragraph 2 7 Entering the number 5 is the third function of this key Downrange V decrements the range and also cancels autorange if selected The secondary func tion of this key is to enter the number 6 Uprange amp increments the range and also cancels autorange if selected The secondary func tion of this key is to enter the number 7 SCANNER SCAN SETUP SCANNER allows you to select the scanner channel limit and scan ner channel number SCAN SETUP allows you to program 2 4 pole operation ratio and scanner trig ger mode See paragraph 2 11 for more scanner in formation The third function of this key is to enter the number 8 for numeric input operations TRIGGER TRIG SETUP TRIGGER triggers in strument readings TRIG SETUP allows you to select the trigger mode delay and interval The default delay is Omsec and the default interval is T 5msec See paragraphs 2 8 and 2 9 for more i
83. intervals or triggers will not cause stepping N19 CHAN 8 MAX Error be closed The closed channel number will appear in the For the following the closed channel number appears in the right most digit of the display 2 pole Limit 4 pole Limit 1 1 12 2 2 3 3 Ni4 4 4 5 4 6 6 4 7 CHAN 4 MAX Error 8 CHAN 4 MAX Error CHAN 4 MAX Error Scan Mode The scan mode commands allow you to scan a complete set of channels per programmed interval continuous trig ger mode or trigger one shot mode with the channel limit determined by the command option For example if a limit of four is set the unit will begin at channel 1 and then scan through channels 2 to 4 with each trigger stimulus or interval N20 Open all channels and terminate scan sequence For the following the closed channel number will appear in the right most digit of the display 2 pole Limit 4 pole Limit N21 1 1 N22 2 2 N23 3 3 N24 4 4 N25 5 CHAN 4 Error N26 6 CHAN 4 MAX Error N27 7 CHAN 4 MAX Error N28 8 CHAN 4 MAX Error Power up DCL SDC Default Upon power up or after a DCL or SDC the NO mode all channels open will be selected NOTES 1 In order to use all eight channels in the 2 pole mode the A and B outputs must be connected in parallel with the DMM inputs as discussed in paragraph 2 11 2 When using the scanner with data store
84. more Translator words already defined enter the following statements in to the computer to retain them as power up default words REMOTE ree QUTFLT 726 SAVES Current Translator words will become power up default words 3 10 8 LIST LIST is a reserved word that can be used to list the existing Translator words stored in temporary memory The most recent defined word will be listed first 3 34 5 1 The U2 command can also be used to list the Translator words see paragraph 3 9 16 2 If there are no Translator words in memory nothing will be displayed when the list is requested Programming Example With Translator words already defined enter he following program statements to list them 1 REMOTE 726 9 4 26 OUTPUT 226 LIST 58 726 58 END ae The second and third statements will send the word list to the computer The Translator words will be displayed 3 10 9 FORGET FORGET is a reserved word that is used to purge all Trans lator words from temporary memory However Translator words that were saved in E7PROM by the SAVE command will again be available after power to the instrument is cycled Reset is RUN or DCL SDC or 10 is sent over the bus IEEE 488 PROGRAMMING _ To purge Translator words from first send the FORGET command and then send the SAVE command ing Example Enter the following statements in to the computer to p
85. only 0 24V C or less Ways to minimize the generation of thermoelectric poten tials include 1 Use only copper wires for all input and output connec tions If lugs are used they should be crimped on not soldered and they should also be made of copper 2 Keep all connecting surfaces clean and free of oxides Wires and lugs should be carefully cleaned before be ing mated together 3 Keep connecting points and junctions at the same temperature 4 Protect all circuits and connecting points from drafts Shielding Shielding is important to keep noise out of low level signal paths To minimize problems in these areas all input and output connections to the scanner card should be made using shielded cable when measuring low level signals The shields should be connected to signal LO not earth ground at the scanner card end for scanner input con nections and at the DMM end for scanner card output connections Note that only one end of the shields should be connected to avoid possible ground loop problems the other ends of the shields should be left floating 2 11 13 Using the Scanner with Other Instrumentation Although the scanner card is intended for use primarily with the Model 199 DMM it can also be used with other instrumentation For example assume that the Model 1992 is to be used with a Keithley Model 181 Nanovoltmeter to make measurements requiring a higher input resistance than is available with the Mo
86. quence must take place to properly send the command In particular the correct listen address must be sent to the instrument before it will respond to addressed commands Table C 3 lists a typical bus sequence for sending an ad dressed multiline command In this instance the SDC command is being sent to the instrument UNL is generally sent as part of the sequence to ensure that no other active listeners are present Note that ATN is true for both the Data DataBus ae State ase Hex Decimal Assumes primary address 26 Table C 4 gives a typical device dependent command se quence In this instance AFN is true while the instrument is being addressed but it is set high while sending the device dependent command string APPENDIX C Table C 4 Typical Device Dependent Command Sequence Data _ command AINE Decimal Assumes primary address 26 IEEE Command Groups Command groups supported by the Model 199 are listed in Table C 5 Device dependent commands are not includ ed in this list Table C 5 IEEE Command Group HANDSHAKE COMMAND GROUP DAC DATA ACCEPTED RFD READY FOR DATA DAV DATA VALID UNIVERSAL COMMAND GROUP ATN ATTENTION DCL DEVICE CLEAR IFC INTERFACE CLEAR LLO LOCAL LOCKOUT REN REMOTE ENABLE SPD SERIAL POLL DISABLE SPE SERIAL POLL ENABLE ADDRESS COMMAND GROUN LISTEN LAG LISTEN ADDRESS GROUP MLA MY LISTEN ADDRESS UNL UNLISTEN TALK T
87. the factory default primary address of 26 2 To exit the program without changing the address press NEXT 3 To change the address key in the desired digits in the range of 0 30 and press NEXT to go on to the following program NOTES 1 If an invalid address is entered the primary address will set to 30 upon exiting the program 2 To change the default address of the instrument first set the address to the desired value and then use the save setup program or send L1 over the bus Cycling power or sending SDC DCL or LO over the bus will not affect the newly saved default primary address If the 488 primary address is changed but not saved cycling power will return the instrument to the original default address However program reset or DCL or SDC commands will not affect the current ad _ dress Sending L0 over the bus will not change the cur rent address but it will change the default address to the new value 4 An UNCAL error will default the address to 26 and the line frequency setting to 60Hz e 2 17 BASIC DMM OPERATION 2 7 4 Line Frequency The programmed line frequency should match that of the power line voltage in order for the instrument to meet its noise specifications at 5 digit resolution line cycle in tegration is used at 5 2 digit resolution The line frequency program can be used to check the programmed line fre quency and set it to 50 or 60Hz
88. the number of sets of data that are stored is determined both by the data store size command as well as the number of channels per scan For example with a programmed size of 400 readings and a scan limit of eight channels 50 sets of data will be stored 400 8 50 3 A CHAN 4 MAX error will occur if you attempt to program a limit greater than 4 with the unit in the 4 pole mode 4 Sending a scanner command with no scanner installed will result in an IDDC error Programming Example lo demonstrate scanner program ming close channel 3 by entering the following statements _ REMOTE 726 DUTPLIT 726 i 5 Note that the closed channel 3 is displayed in the right most digit To open the channel and return the display to normal enter the following statement OUTPUT Tee 3 12 2 Pole Ratio Mode O The command controls 2 4 pole normal mode opera tion as well as 2 4 pole ratio operation In the 2 pole mode up to eight channels can be scanned while a maximum of four channels can be scanned in the 4 pole mode NOTE If you attempt to program the 4 pole mode with channels 5 8 already closed the pole mode will not be changed and a CHAN 4 MAX error will occur The closed channel will not be opened In the ratio mode the unit computes the ratio between the channel 2 through 8 reading to the channel 1 reading in order to determine ratio the unit first takes a reading on cha
89. the programmed interval The filter status resolution and function affects the overall reading rate and thus the maximum scanning rate For the fastest scan rate for a given function turn off the filter select 442 digit resolution and turn off the multiplexer Each scan sequence can be triggered from the front panel with an external trigger pulse by setting up the unit as follows 1 Select the range and function as required 2 Press SHIFT TRIG SETUP and program the unit for the one shot trigger mode Press NEXT and program the desired trigger delay Press NEXT twice to return to normal display Press SHIFT SCAN SETUP and program the pole mode as required Press NEXT to advance to the scan mode menu then use uprange or downrange to select the SCAN mode Press NEXT to program the ratio and to return to nor mal display Press SCANNER and program the channel limit as desired Press TRIGGER or apply an external trigger pulse to initiate the first scan SEQUENCE The unit will scan all channels in the set and then stop One trigger per SCAN SEQUENCE will be required cancel the scan mode program a channel limit of 0 do so press SCANNER 0 2 33 BASIC OMM OPERATION NOTES 1 Because of the rapid scan sequence in the scan mode it is recommended that this mode be used with data store as discussed in paragraph 2 11 11 The unit will displa
90. to 26 and the line frequency to 60Hz KEITHLEY 199 SYSTEM OMM SCANNER BASIC DMM OPERATION VOLTS OHMS H 5 MAX 2 300v MAX INPUT FRONT REAR Figure 2 1 Model 199 Front Panel 2 3 FRONT PANEL FAMILIARIZATION The front panel of the Model 199 is shown in Figure 2 1 The following paragraphs describe the various components of the front panel in detail 2 3 1 Display and Indicators Display The 10 character alphanumeric LED display is used to display numeric data range and functions mnemonics for example mV as well as messages When the optional Model 1992 Scanner is being used the chan nel number is displayed in the right most digit Function Indicators The indicator or indicators that are on identify the measurement function presently selected Range Indicator The AUTO indicator will be on when autoranging is selected Manual ranging is in effect when AUTO is off Zero Indicator ZERO will be on when the zero mode is enabled Zero is used to subtract a baseline value from the measured signal ZERO will flash when zero has been enabled but a reading that has yet to be triggered Filter Indicator FLTR indicates when the running average filter is enabled A flashing FLTR indicates the filter has not yet settled and shows the update rate Remote Indicator REM shows when the Model 199 is in the IEEE 488 remote state See Section 3 for more detailed IEEE 488 in
91. ve display is 0 000000 0 COMMENTS _ 18 REMOTE 726 a Place 199 in remote 15 251 Beles aue IHPUT COMMAND STR IHG A Prompt for and input command zB F285 Address 199 to listen send string 48 ENTER 726 BS Address 199 to talk input reading SH PRINT Display reading string GOTO 28 Repeat r EMD a NOTE For conversion to a numeric variable change the program as follows EHTER S APPENDIX 8 HEWLETT PACKARD MODEL 9825A Use the following program to send a command string to the Model 199 from a Hewlett Packard Model 9825A and display the instrument reading string on the computer printer The computer must be equipped with the HP98034A HPIB Interface and a 9872A extended I O ROM DIRECTIONS 1 From the front panel set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the 98034A HPIB interface installed in the 9825A 3 Enter the lines in the program below using the STORE key after each line Line numbers are automatically assigned by the 9825A 4 Press the 9825A RUN key and type in the desired command string at the command prompt For example to place the instrument in ACV and autorange type in FIROX and press the CONT key 5 The instrument reading string will then piu on the typical display is NACV 0 000000E 0 PROGRA
92. 09 151 65 U11 U12 10 8 CHANNEL SOURCE DRIVER UDN2585 405 013 014 INVERTER 74HCO4 354 015 016 EDGE TRIG FLIP FLOP 74HCT374 397 U17 IC QUAD 2 INPUT NOR GATE 74AHCTO2 IC 510 U2 IC MICROPOWER BIPOLAR MONOLITHIC 6728 IC 177 U20 IC PROGRAMMABLE E2ROM 2816A LSI 83 U3 IC DUAL 4 BIT COUNTER 74HCT393 1 462 U4 iC 32Kx8 EPROM 27C256 199 800 U5 IC GPIB ADAPTER 9914A LSI 49 16 IC OCTAL INTERFACE BUS 75160 298 07 IC OCTAL INTERFACE BUS 75161 299 IC VERSATILE INTERFACE ADAPTER G65SC22 51 86 99 8 8 HI SPEED STATIC CMOS RAM 6264 LSI 66 w3 JUMPER J 15 Y1 CRYSTAL 8 0000MHZ CR 24 1 Order level of firmware in unit 12464 REVISED 12652 REVISED 13427 ADDED 90 69 FOR D 12880 14599 CS 713 WAS CS 278 15223 ARTWORK FROMREVDTOE ___ 44 pa o0 o0 Figure 7 3 Digital Board Component Location Drawing Dwg No 199 100 85 RIRI 8828822R CLOCK J30 ON 1992 102 OPTION BOARD VIA SUPPLIED CABLE WETH OPTION Jes 3 1 NC 50 838888 8 50 59 59 Q 14014 14 014 m sf 24HC04 74H004 5 04 Y ube MECN EN 254 C lC 21
93. 0E 0 e PROGRAM NM COMMENTS CLE Clear screen a 20 HAf GPIEB CALLIBFIHD Find board descriptor ERIS Ha g DgU1 CALL Find 199 descriptor MLA Muzg CALL IBPAICHMISSAE UM Set primary address to 26 Sa 15 1 CALL TESRECER DG Set REN true LHPUT COMMAND STRINGS SCE Prompt for command string 65 L SCT CHESCiZO CHRSCi Add CR lt gt to command string CALL TBWRT CE _ Send command string to 199 RE SPACES 25 Dimension reading input string CALL RED Get reading string from 199 198 PRINT RE Display reading string on iim GOTO SA Repeat NOTES 1 For conversion to numeric variable modify the program as follows R URLCHIDBTAZRE S Se 1222 163 PRINT 2 In order for Translator to function properly a lt CR gt lt LF gt sequence must be added to the end of any Translator execution string sent tothe instrument See line 65 above for an example B 2 APPENDIX OR AT PC 488 INTERFACE The following program sends a command string from an IBM PC or AT computer and displays the instrument reading string on the computer CRT The computer must be equipped with the Capitol Equipment Corp 488 IEEE 488 interface The interface card must be set to memory address of 400 as described in the PC 488 Instruction Ma
94. 1 C199 309 7 LU 100 B199 306 C199 304 FA 72 D199 302 706 316 C199 307 A199 317 A199 316 TABLE 7 5 Model 1992 PARTS LIST CIRCUIT DESIG DESCRIPTION KEITHLEY PART No C1 C3 C2 C4 C5 J1 J2 J30 K1 K8 P1 1 2 P29 P30 Qt R1 R2 R3 U1 u2 U3 Wi CABLE ASSEMBLY CABLE ASSEMBLY SCANNER BOARD SHIELD CAP 10uF 20 100 25V ALUM ELEC CAP 1uF 20 50V CERAMIC DIODE SILICON 1N4148 CONN 10 PIN OPEN END HEADER CONN STRAIGHT POST HEADER 3 PIN RELAY DPST CABLE ASSEMBLY 10 CONDUCTOR CONN PLUG 10 PIN W STRESS RELIEF CONN HOUSING 3 PIN TRANS N CHAN MOSPOW FET 2N7000 RES 10K 5 1 4W COMPOSITION OR FILM HES 330 596 1 4W COMPOSITION OR FILM RES 470 5926 1 A4W COMPOSITION OR FILM IC DUAL D TYPE FLIP FLOP 74HC74 16 8 SERIAL IN LTCH DRIVE UCN 5841A IC OPTOCOUPLER 2601 JUMPER CIRCUIT CONN BERG 3 PIN CA 64 1 CA 64 2 B1992 301 C 314 10 C 365 1 RF 28 CS 626 10 CS 533 3 RL 77 CA 32 6 CS 611 10 CS 534 3 J 15 CS 339 3 Revrsron _ 12556 ReLERSED c 12664 REVISED fez 22 13000 a 2 2 90 oo Figure 7 7 Model 1992 Component Location Drawing Dwg No 1992 100 506 J30 R2 OUTPUT A i ls Hi Lo TO J29 199 102 _ 580 id SEE SCHEMATIC gt lt lt z 0199 1062 J30
95. 2 2 2 2 2 14 4 Pole Resistor Test Connections Eo geet POCHE nad 215 Amplifier Gain Test MTM 2 16 Amplifier Frequency Response Test Configuration 2 7 Using Scanner Card with ene SECTION 3 488 Programming 31 Typical Program Flow Chart PE iud 3 2 IEEE 488 Connector VAS Pp EAERI E SERE 3 3 IEEE 488 Connections LEE LI EE 3 4 IEEE 488 Connector 3 5 Contact Assignments m 3 6 General Dat Format 37 5 Mask and Serial Byte Format d ARM GN REM 3 8 UO Machine Status Word and Default Values m NOM TTE 3 9 01 Error Status Word 3 10 2 Pole Resistor Test Connections a Li und P exile eue e iu edes dur 3 1 4 Pole Resistor test Connections Tr p a e 312 Amplifier Gain Test 8 D SECTI
96. 22A U25C 032 SIG Q13 U22A Q35 SIG ZERO Q3 U22A Q34 CAL ZERO 02 Q3 U22A U25D Q32 CAL 03 Q3 U22A U25C Q32 SIG U22A Q35 300mV AC ZERO U23A U23B U25D Q32 CAL 02 U23A U23B U25C Q32 SIG 03 U23A U23B U25A Q32 No Test 04 U21C U25D Q32 021 0256 032 U21C U25A Q32 No Test ZERO U21B U25D Q32 CAL U21B U25C 032 SIG U21B U25A Q32 No Test U23C U21B U25D Q32 U23C U2IB U25C Q32 U23C U21B U25A Q32 No Test SENSE LO REF HI REF LO SENSE U22D U24D 0220 U24D 0220 U24D 0220 9240 1248 032 Q35 012 U25A 032 Q30 0248 Q32 SENSE LO 011 0220 U24D SEES 6666 8666 6666 REF 0220 0240 035 Q12 REF LO 011 0220 0240 U24A 032 SENSE HI QU 0220 0245 030 6 19 MAINTENANCE Table 6 11 Model 199 Troubleshooting Mode Cont Function Input amp Measurement Buffer Relays Range Switches Multiplex Range Phase N Mode Gain Closed Closed Switches Closed 30k 01 xi U22C U24C U248 Q32 U22C U24C Q35 012 U22C U24C U24A Q32 U22C U24C Q30 SENSE LO REF HI REF LO SENSE HI 5505 SENSE LO REF HI REF LO SENSE HI QD
97. 4 MAX ERROR STEP N10 Stop scan all channels open 2 Pole Limit 4 Pole Limit NH 1 1 2 2 NB 3 3 4 4 N15 5 CHAN 4 MAX ERROR N16 6 CHAN 4 MAX ERROR 7 CHAN 4 MAX ERROR 18 8 4 N19 CHAN 8 MAX ERROR CHAN 4 MAX ERROR SCAN N20 Stop scan all channels open 2 Limit 4 Pole Limit N21 1 1 N22 2 2 N23 3 3 N24 4 4 N25 5 CHAN 4 MAX ERROR N26 6 CHAN 4 MAX ERROR N27 7 CHAN 4 MAX ERROR N28 8 CHAN 4 MAX ERROR POLE RATIO 2 pole Oi 4 pole 02 2 pole ratio 4 pole ratio SCAN INTERVAL 00 Default 175msec interval SELECT OFF Qn n interval in msec 15 999999msec TRIGGER DELAY Wn n delay in msec 0 999999msec Delay to be used as channel settling time DATA FORMAT Mantssa 6 1 2 Digits Sufler Locaton G2 G3 G6 G7 Channel G4 G5 G6 G7 1 234567 1 B400 C8 CR LF N x Normal Overflow Zs 29064 712 Terminates Buffer Prefix Exponent DOV DC Volts ACY AC Volts OHM Ohms 061 DC Amps AC AC Amps AC dB Volts dBl AC dB Amps RAT Ratio Notes 1 Buffer Location 8000 with Data Stora Disabled 2 Channel 0 with no Scanner Scanner Dis STATUS WORD FORMATS U0 Status Word Format FACTORY DEFAULT m 1000000 00 00000 416 000000 39 K NNO P 000000 S WWWWWW Y Z SW SCANNER U1 Status Word Format 1 TRIGGER OVERRUN 1 INTERVAL OVERAUN 40 1 OF 03 199 Gi 0
98. 6 6 7 7 68 68 1 6 8 2 6 8 3 Installation TD METER T US T T Relay Shield Jumper rh EAE Ron ea e aia en INTRODUCTION eee ewe ten 22 10 4 4 1 2 2 2 2222 2 Rim m LINE VOLTAGE SELECTION mov FUSE REPLACEMENT ee MORE PES Lr Xo 108 Line iaa pecudes dante krina didam roe CALIBRATION Sw ro EUM a a Recommended Calibration Equipment HR RED PONI Rer s Fate Environmental Conditions nap P eU PUR ee ented Subtus Warm Up Period vibra uds pm CAL Lock Switch c Front Panel Calibration m TENE pm E ee IEEE 488 Bus punt Poni e EN Calibration Sequence qu eie DC Volts Calibration Ui ekle aiia CREE d S ee dada Resistance Calibration equ TTE 22 TRMS Volts Calibration v Rn DC Current Calibration FOE
99. 8 IF 17562 12 THEM 118 Wait for SRO on data store full 128 7262 Clear SRO 1465 FEE TSEIHiBXUC Data from data Store stop scan 158 OUTPUT TIS t GER Format with loca tions channels Loop for all 80 readings 178 726 A Get 199 reading PRINT Display reading 136 HEST I Loop back for next reading 268 3 12 5 Testing Resistors The Model 1992 Scanner adds versatility to the Model 199 by allowing the unit to test multiple sources One possi ble application for the scanner would be to test multiple resistors and compare their values with a precisely known reference resistance The ratio mode could be used to deter mine the degree of variability among the various resistors The following paragraphs discuss connections for 2 pole and 4 pole testing of resistors and also list a sample pro gram for doing so Connections Typical connections for 2 pole and 4 pole modes are shown in Figures 3 10 and 3 11 The 4 pole mode is recommend ed for making measurements on the 3000 and 30kQ ranges in order to attain rated accuracy For the 2 pole mode the reference resistor should be connected to chan nel 1 only in the case of the 4 pole mode the reference resistor is connected to both channel 1 and 5 The resistors being compared are connected to the remaining channels as indicated The scanner output connections also differ For the 2 pole mode F
100. 8 bus calibration proceed as follows A Set the AC voltage calibrator to output 300 000mV at 500Hz B After allowing sufficient time for the calibrator voltage to settle send the following commands over the bus 00 3 C Set the AC calibrator to output 30 000mV at 500 2 D After allowing sufficient time for the calibrator 5 voltage to settle send the following command over the bus Both calibration constants will automatically be stored in EPROM E Repeat steps A through D for the remaining ACV ranges using Table 6 7 as a guide High Frequency Check 70kHz A With the AC VOLTS function autorange and 5 d resolution selected connect the AC calibrator to the instrument as shown in Figure 6 6 B Set the AC calibrator to output 100 000V at a frequen of 70kHz and allow sufficient time for the measurement to settle reading is not 100 000V 1800 counts then omit steps D through E and proceed to step 6 68 jm MAINTENANCE Table 6 7 TRMS AC Volts Calibration 199 199 Calibration AC Calibrator Voltage IEEE 488 Range Point Setting 500Hz Bus Commands V300E 3XCOX V30E 3XCIX V300E 3XC1X V30XCOX V3XCIX V300XCOX V30XCIX D Set the AC calibrator to output 10 0000V at 70kHz and D After allowing sufficient time for the measurement to allow the measurement to settle settle use an insulated alignment tool to adjust t
101. 88 bus Through this command the user has a choice of data from the A D converter normal DMM readings or the buffer data store The reading mode com mands are as follows BO A D converter readings 1 Single Data Store readings B2 All Data Store readings Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition When in normal A D readings will be sent In a con tinuous trigger mode readings will be updated at the con version rate The 1 command is used to access single readings from the buffer When the B1 command is sent subsequent readings will be taken from consecutive buf fer locations beginning with the first memory location 001 Once all readings have been requested the last loca tion will be continuously sent The B2 command allows you to dump the entire data store contents to the computer in one operation Individual readings will be separated by commas and the selected data format will apply to each reading Data fields not ap plicable to the requested operation will be filled with zeroes Also the programmed terminator and EOI will be asserted at the end of the complete dump not after each reading as is the case with the 1 mode NOTE In B1 or B2 nothing will be transmitted over the bus until data is stored in data store ing Example Enter the following statements in to the computer to send a reading over the bus
102. 9 microprocessor The MPU has direct control over the display front panel switches A D converter 488 bus scanner as well as the VOLTMETER COMPLETE Output and the EXTERNAL TRIGGER Input Timing for the micro processor is accomplished by the use of Y1 an 8MHz crystal This frequency is divided down by four to obtain a bus operating frequency of 2MHz by the MPU U10 Instrument operation software is stored in the EPROM U4 Calibration constants Translator words and instrument set up conditions are stored in EPROM 020 U9 is the RAM The chip selected is determined by the state of 12 A13 and 15 address lines These address lines determine which is selected by the decoder U1 Only one device ROM RAM VIA etc will have access to the data bus at any one time The heart of the IEEE 488 circuitry is the General Purpose Interface Bus Adapter U5 The GPIBA is capable of per forming all IEEE talker listener protocols The bidirectional data lines 20 through D7 permit the transfer of data bet ween the microprocessor and the GPIBA The transceivers U6 and U7 are used to drive the output Data is buffered by U6 and U7 and is transmitted to the bus via connector 17 5 6 2 Display Circuitry display information is sent through display latches U16 and U15 Upon each display update new segment infor mation is presented to the display latches and a clock pulse is sent on PAO The clock pulse to U4 and
103. 992 8 Channel Scanner Model 1993 Quick Disconnect Scanner Connector Kit Model 1998 1 Single Fixed Rack Mounting Kit Model 1998 2 Dual Fixed Rack Mounting Kit Model 1651 50 Ampere Shunt Model 1681 Clip On Test Lead Set Model 1682A RF Probe Model 1685 Clamp On Current Probe Model 1751 General Purpose Test Leads Model 1754 Universal Test Lead Kit Model 5806 Kelvin Clip Leads Model 7007 1 Shielded IEEE 488 Cable im Model 7007 2 Shielded IEEE 488 Cable 2m IEEE 488 Cable 0 9m 3 ft IEEE 488 Cable 1 8m 6 ft Model 7008 3 Model 7008 6 STORAGE amp SCANNING CAPABILITIES 199 Front Panel Operation TRIG SETUP SHIFT TRIG SETUP to enter menu NEXT to scroll to next menu option CONTINUOUS Reading scanning and storing rates controlled by INTERVAL Trigger LONE SHOT DELAY Osec to 999 999sec SELECT OFF Interval gt 175msec depending on other programmed parameters INTERVAL A Y SELECT User programmed interval 15 to 999 9995 DMM SETUP SHIFT DMM SETUP to enter menu NEXT to scroll to next menu option REV Displays current software revision level MUX OFF Turns off autocal routines for faster reading rates MUX L MUX ON Recommended for best accuracy IEEE Use numeric keys to program IEEE 488 primary ad dress 0 30 2 50 2 Line frequency FREQ L FREQ 60HZ Line frequency SAVE YES Saves present configuration SAVE L
104. A 30mA 300 0 Auto Auto R2 3V Auto Auto R3 30V 30 30kQ Auto Auto R4 300V 300V 3A 300k2 Auto Auto R5 300 300V 3A Auto Auto R6 300v 300V 30M2 Auto Auto R7 300V 300 300M2 Auto Auto ZERO Z0 Zero disabled 71 Zero enabled Z2 Zero enabled using a zero value FILTER Internal and front panel filter disabled P1 Internal filter enabled P2 Front panel filter enabled RATE 50 4 4 digit resolution 2 59msec integration period 51 5 2 digit resolution line cycle integration 16 67msec 60Hz 20msec 50Hz TRIGGER MODE TO Continuous on Talk Ti One shot on Talk T2 Continuous on GET T3 One shot on GET T Continuous on X T5 One shot on X 76 Continuous External Trigger 17 One shot on External Trigger READING MODE BO Readings from A D converter B1 Individual readings from data store B2 All readings from data store buffer dump DATA STORE SIZE 10 Wrap around data store mode In Data store of n n 1 to 500 INTERVAL 00 Default interval 175 5 SELECT OFF Qn n interval in milliseconds J5msec to 999999msec VALUE V nn nnnn Calibration value zero value Ven nnnnnnE n CALIBRATION Calibrate first point using value Calibrate second point using value C2 Calibrate third point using value DEFAULT CONDITIONS 10 Restore factory default conditions and save 11 Li Save present machine states as defau
105. AG TALK ADDRESS GROUP TALK ADDRESS UNT UNTALK TALK ADDRESS ADDRESSED COMMAND GROUP ACG ADDRESSED COMMAND GROUP GET GROUP EXECUTE TRIGGER GTL GO TO LOCAL SDC SELECTIVE CLEAR STATUS COMMAND GROUP RQS REQUEST SERVICE SRQ SERIAL POLL REQUEST STB STATUS BYTE EOI END C7IC 8 KEITHLEY Service Form Model No Serial No Date Name and Telephone No Company List all control settings describe problem and check boxes that apply to problem Intermittent Analog output follows display Particular range or function bad specify IEEE failure 3 Obvious problem on power up d Batteries and fuses are OK Front panel operational All ranges or functions are bad Checked all cables Display or output check one Drifts 3 Unable to zero 1 Unstable Will not read applied input Overload Calibration only Certificate of calibration required Data required attach any additional sheets as necessary Show a block diagram of your measurement system including all instruments connected whether power is turned on or not Also describe signal source Where is the measurement being performed factory controlled laboratory out of doors etc What power line voltage is used Ambient temperature F Relative humidity __ Lo Other Any additional information If special modifications have been made by the user please de
106. APPENDIX ASCII CHARACTER CODES AND IEEE 488 MULTILINE INTERFACE COMMAND MESSAGES Decimal Hexadecimal ASCH IEEE 488 Messages 96 60 97 Ei MSA 1 PPE 98 62 b MSA 2 PPE 99 63 c MSA 3 PPE 100 64 MSA 4 PPE 101 65 MSA 5 192 66 lp MSA 6 103 67 g MSA 7 PPE 104 68 h MSA 8 105 69 i MSA 9 PPE 106 6A j MSA 10 107 6B k MSA 108 6C 1 MSA 12 PPE 109 6D m MSA 13PPE 110 6E n MSA 14 PPE TH 6F o MSA 15 PPE 112 70 po MSA 16 PPD 113 71 4 MSA 17 14 72 r MSA 18 PPD 15 73 E MSA 19 PPD 116 t MSA 20 PPD 117 75 u MSA 21 118 76 v MSA 22 PPD 119 77 w MSA 23 PPD 120 78 x MSA 24 PPD 121 79 MSA 25 PPD 122 7 2 MSA 26 PPD 123 7B MSA 27 PPD 124 7C MSA 28 PPD 125 7D MSA 29 PPD 126 MSA 30 PPD 127 7F DEL Message send or received with ATN true Numbers represent secondary address values resulting in MSA My Secondary Address m mu 4 CONTROLLER PROGRAMS The following programs have been supplied as a simple aid to the user and are not intended to suit specific needs Each program allows you to send a device dependent command string to the instrument and obtain and display an instrument reading string Programs for the following controllers are included IBM or AT with National Instruments GPIB PC IEEE 488 Interface IBM PC or AT with Capitol Equipment Corp PC 488 Interface
107. DC volts TRMS AC volts ohms TRMS AC amps and DC amps These procedures are intended for use only by quali fied personnel using accurate and reliable test equipment If the instrument is out of specifications and not under warranty refer to Section 6 for calibration procedures WARNING The maximum common mode voltage voltage between input low and chassis ground is 500V peak Exceeding this value may cause a break down in insulation creating a shock hazard Some of the procedures in this section may ex pose the user to dangerous voltages Use stan dard safety precautions when such dangerous voltages are encountered 4 5 1 DC Volts Verification With the Model 199 set to 5124 resolution verify the DC volts function as follows CAUTION Do not exceed 300V between the input HI and LO terminats or damage to the instrument may occur 1 Select the DCV function and autorange 2 Connect the DC voltage calibrator to the Model 199 as shown in Figure 4 1 3 Set the calibrator to and enable zero on the Model 199 Verify that the display is reading 000 000mV 2 counts NOTE Low measurement techniques should be used when checking the 300mV DC range Refer to para graph 2 6 5 for low level measurement considera tions 4 Set the calibrator to output 300mV and verify that the reading is within the limits listed in Table 42 5 Disable zero and leave it disabled for the remainder of the DCV verification procedure
108. E 488 bus as follows 1 Line up the cable connector with the connector located on the rear panel of the instrument The connector is designed so that it will fit only one way Figure 3 4 shows the location of the 488 connector on the instrument 2 Tighten the screws securely but do not overtighten them 3 Add additional connectors from other instruments as required 4 Make certain that the other end of the cable is properly connected to the controller Most controllers are equipped with an IEEE 488 style connector but a few may require a different type of connecting cable Con sult the instruction manual for your controller for the proper connecting method IEEE 488 INTERFACE Figure 3 4 IEEE 488 Connector Location NOTE The IEEE 488 bus is limited to a maximum of 15 devices including the controller The maximum cable length is 20 meters or 2 meters times the number of devices which ever is less Failure to observe these limits may result in erratic bus operation Custom cables may be constructed by using the informa tion in Table 3 2 and Figure 3 5 Table 3 2 lists the contact assignments for the bus and Figure 3 5 shows the contact configuration CAUTION 488 common is connected to digital com mon Maximum voltage between digital com mon and earth ground is 30V CONTACT 24 Figure 3 5 Contact Assignments 488 PROGRAMMING Table 3 2 IEEE Contact Designations
109. ER poe KR Mira de TFC Interface 2 2 94 2 3 0 Local Lockout TAMEN NE o us DCL Device Clear eeno PEPPER 3 8 6 3 8 7 3 8 8 3 9 3 9 1 3 9 2 3 9 3 3 9 4 3 9 5 3 9 6 3 9 7 3 9 8 3 9 9 3 9 10 3 9 1 3 9 12 3 9 13 3 9 14 3 9 15 3 9 16 3 9 7 3 9 18 3 9 19 3 9 20 3 9 21 3 10 3 10 1 3 10 2 3 10 3 3 10 4 3 10 5 3 10 6 3 10 7 3 10 8 3 10 9 1 312 3 12 1 3 32 2 3 12 3 3 12 4 3 12 5 3 12 6 SECTION 4 Performance Verification 43 4 2 4 3 44 45 4 5 1 4 5 2 4 5 3 4 54 4 5 5 SDC Selective Device Clear GET Group Execute Trigger Serial Polling SPE SPD DEVICE DEPENDENT COMMAND PROGRAMMING pon Bep EE Aik NOE Execute X Function F n Range Z ee tmr Rm Rate S Trigger Mode Reading Mode B Data Store Interval Q and Size I I EN NAR TEE E Value V and Calibration C Default Conditions L Data Format SRQ Mask and Serial EOI and Bus Hold off Modes
110. G commands are as follows G0 Reading with prefix only Example 1 234567 0 G1 Reading without prefix Example 1 234567 0 G2 Reading and buffer memory location with prefix Example 1 234567 0 001 G3 Readings and buffer memory without prefix Example 1 234567 0 001 G4 Reading and channel with prefix Example NDC 1 234567E 0 C1 G5 Reading and channel without prefix Example 1 234567 0 1 G6 Reading memory buffer location and channel with prefix Example NDCV 1 234567E 0 B001 C1 G7 Reading buffer memory location and channel without prefix Example 1 234567E 0 001 01 Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition Notes 1 The B command affects the source of the data In the BO mode the bus data will come from the A D converter In the B1 and B2 modes the data will come from the buffer 2 Programmed terminator and sequences appear at the end of each reading except in B2 which terminates only at the end of the string 3 If a buffer location or channel is not available zero is sent G6 Example NDCV 2 000000E 1 B000 C0 4 All 9s appear in the data field for an overflow Programming place the instrument in the G1 mode and obtain a reading enter the following statements into the keyboard 18 REMOTE TZE 28 OUTFUT Fees ENTER 26
111. ING 3 12 1 Scanner Setup N The scanner setup command allows you to control chan nels individually scan one channel per trigger or interval or scan one set of channels per trigger or interval as discussed below Manual Channel Control The commands below open all channels or close each in dividual channel by sending the appropriate command NO All channels open For the following commands the indicated channel will right most digit of the display Closed Channel 2 Pole 4 Pole Ni 1 1 N2 2 2 N3 3 23 N4 4 4 N5 5 CHAN 4 MAX Error N6 6 CHAN 4 MAX Error N7 7 CHAN 4 MAX Error N8 8 CHAN 4 MAX Error N9 CHAN 8 MAX CHAN 4 MAX Error Step N10 N18 In the step mode the instrument scans one channel per interval continuous trigger mode or one channel per trig ger one shot trigger mode With each interval or trigger the instrument closes a channel takes a reading and then opens that channel Subsequent intervals or triggers ad vance channels to repeat the sequence The number of channels per step sequence is determined by the command option used which also sets the chan nel limit The reading interval is set by the command discussed in paragxaph 3 12 3 Available triggers include front panel external trigger input rear panel and 488 talk GET and X commands The trigger source is determined by the T command N10 Open all channels and stop step sequence Subse quent
112. INTERVAL OVER RUN message The interval cannot be programm ed if the unit is in the one shot trigger mode Reading interval can be checked or programmed with the TRIG SETUP key as follows 1 Press SHIFT TRIG SETUP and then NEXT repeatedly until the following is displayed INTERVAL 300msec trigger delay the unit will wait 300msec after each trigger before taking a reading The allowable range for the trigger delay period is between 0 and 999 999 seconds in one millisecond increments The trigger delay can be programmed with the TRIG SETUP key as described below 1 Press SHIFT TRIG SETUP and then NEXT and note the following message is displayed briefly DELAY 000 000S Here we have assumed the factory default delay period of Osec 2 Using the the data entry keys 0 9 key in the desired trigger delay period in the range of 0 999 999sec 3 Once the desired delay value is programmed press NEXT to go on to the interval selection or press NEXT once more to return to normal display 2 8 4 Reading Interval The reading interval parameter determines the time period Next the unit displays SELECT OFF SELECT 2 Use uprange or downrange to select the desired inter val type select or default then press NEXT If default SELECT OFF is selected the interval will be set to l75msec and the unit will return to normal display 3 If select interval is chosen the presently selected int
113. Keithley Instruments Avelingen West 49 4202 MS Gorinchem Postbus 559 4200 AN Gorinchem 01830 35333 Fax 01830 30821 SWITZERLAND Keithley Instruments SA Kriesbachstrasse 4 8600 D bendorf 01 821 9444 Fax 01 820 3081 TAIWAN Keithley Instruments Taiwan 3rd Floor Number 6 Section 3 Min Chuan East Road Taipei R O C 886 2 509 4465 Fax 886 2 509 4473 Model 199 System DMM Scanner Instruction Manual 1988 Keithley Instruments Inc Test Instrumentation Group All rights reserved Cleveland Ohio U S A July 1987 Fourth Printing Document Number 199 901 01 Rev D SAFETY PRECAUTIONS The following safety precautions should be observed before operating the Model 199 This instrument is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury Read over the manual carefully before operating this instrument Exercise extreme caution when a shock hazard is present at the instrument s input The American National Standards Institute ANSI states that a shock hazard exists when voltage levels greater than 30V rms or 42 4V peak are present A good safety practice is to expect that a hazardous voltage is present in any unknown circuit before measuring Inspect the test leads for possible wear cracks or breaks before each use If any defects are found replace the test leads For optimum safe
114. M RES 270 526 1 4W COMPOSITION OR FILM RES 360 5 1 4W COMPOSITION OR FILM RES 330 595 1 4W COMPOSITION OR FILM TG 200 TG 138 TG 196 A199 600 193 603 TG 195 TG 174 A31841 TG 128 A197 600 R 76 1M R 344 100K 214 177 3 R 88 100K R 348 30K R 263 13K R 88 1M 348 2 263 1 002 R 76 1K R 262 1 R 1 22M R 168 118K R 352 1 17M R 336 20K R 263 9 09K R 88 32 4K R 263 20K 88 R 88 15 8K R 88 7 87K 176 142 8 8 264 996 7 R 263 6 19K R 348 9K R 88 15K R 88 14K R 246 10 R 88 12 4K R 88 9 76K R 76 220 R 176 7 78K R 88 162K R 76 7 5K R 76 270 R 76 360 R 76 330 R87 R88 R98 H89 R95 R9 R96 H97 HT1 S1 S2 53 T1 T1 TE1 TE2 U11 U13 019 016 017 U18 U2 U4 U5 U42 U20 U21 U25 U26 U27 U28 U29 U32 033 043 044 045 046 049 050 051 052 053 U6 U7 U8 VR2 Y1 Maiched set order 196 602 RES 470 5 1 4W COMPOSITION OR FILM RES 10K 5 1 4W COMPOSITION OR FILM RES 100K 5 1 4W COMPOSITION OR FILM RES 10 2 25 RES 200 5 1 4W COMPOSITION OR FILM RES 1 18K 1 1 8W METAL FILM THERMISTER 250mSEC 500V SWITCH PUSHBUTTON SWITCH PUSHBUTTON 6 POLE SWITCH SLIDE DPDT TRANSFORMER 90 110V 180 220V TRANSFORMER 105 125V 210 250V TERMINAL 22 OP AMP NESS34N SELECTED IC 283 IC DUAL 4 BIT DEC BIN COUNT 74HC390 IC DUAL 4 BIT COUNTER 74HCT393 PWR OFFSET VOLT
115. M COMMENTS dim amp L 253 E Lz251 Dimension data strings 1 1329 726 Define 199 at address 26 Place 199 in remote ent COMMAND STRING 1 BE Prompt for command string 4 wrt s 128 Address 199 to listen send string S red 199 Address 199 to talk input data amp prt F Print data string on printer gto 2 Repeat NOTE For conversion to numeric variable modify the program as follows amp prt 515 B7 APPENDIX DEC LSI 11 The following program sends a command string to the Model 199 from a DEC LSI 11 minicom puter and displays the instrument reading string on the DEC CRT terminal The LSI 11 must be configured with 16K words of RAM and an IBV 11 IEEE 488 interface The software must con figured with the IB software as well as FORTRAN and the RT 1 operating system DIRECTIONS 1 From the front panel program feature set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the IBV 11 IEEE 488 interface cable 3 Enter the program below using the editor under RT 11 and the name IEEE FOR 4 Compile using the FORTRAN compiler as follows FORTRAN IEEE 5 Link with the system and IB libraries as follows LINK IEEE IBLIB 6 Type RUN IEEE and press the RETURN key 7 The display will read ENTER ADDRESS 8 Type in 26 and press the RETURN key 9 The display will read TEST SETUP 10
116. Model 199 talker capabilities exist only after the instrument has been addressed to talk L Listener The L function defines the ability of the Model 199 to receive device dependent data over the bus Listener capabilities exist only after the instrument has been addressed to listen SR Service Request The SR function defines the ability of the Model 199 to request service from the controller RL Remote Local The RL function defines the capabili ty of the Model 199 to be placed in the remote or local modes PP Parallel Poll The Model 199 does not have parallel polling capabilities DC Device Clear The DC function defines the ability of the Model 199 to be cleared initialized DT Device Trigger The ability for the Model 199 to have its readings triggered is defined by the DT function C Controller The Model 199 does not have controller capabilities Du tee TE Extended Talker The Model 199 does not have tended talker capabilities LE Extended Listener The Model 199 does not have ex tended listener capabilities E Bus Driver Type The Model 199 has open collector bus drivers Table 3 3 Model 199 interface Function Codes Source Handshake capability Acceptor Handshake capability Talker Basic talker Serial poll Unaddressed to talk on LAG Listener Basic listener Unaddressed to listen on TAG Service Request capability Remote Local capability No Parallel Poll capabili
117. Model 199 System DMM Scanner Instruction Manual Contains Operating and Servicing Information KEITHLEY WARRANTY Keithley Instruments Inc warrants this product to be free from defects in material and workmanship for a period of 1 year from date of shipment Keithley Instruments Inc warrants the following items for 90 days from the date of shipment probes cables rechargeable batteries diskettes and documentation During the warranty period we will at our option either repair or replace any product that proves to be defective To exercise this warranty write or call your local Keithley representative or contact Keithley headquarters in Cleveland Ohio You will be given prompt assistance and return instructions Send the product transportation prepaid to the indicated service facility Repairs will be made and the product returned transportation prepaid Repaired or replaced products are warranted for the balance of the origi nal warranty period or at least 90 days LIMITATION OF WARRANTY This warranty does not apply to defects resulting from product modification without Keithley s express written consent or misuse of any product or part This warranty also does not apply to fuses software non rechargeable batteries damage from battery leakage or problems arising from normal wear or failure to follow instructions THIS WARRANTY 15 IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCL
118. ON 4 Performance Verification 4 1 Connections for DC Volts Verification ete eee MONS 4 2 Connections for TRMS AC Volts NEP 4 3 Connections for Ohms Verification 3000 30k0 4 4 Connections for Ohms Verification 300k0 300MQ Ranges EE 4 5 Connections for DC Current Verification 4 6 Connections for TRMS AC Current Verification T vii SECTION 5 Principles of Operation 51 Overall Block Diagram ri st 5 2 Input Configuration During 2 and 4 terminal Resistance Measurement 5 3 _ Resistance Measurement peat cane Circuitry Coren 5 4 JFET Multiplexer M 5 5 Multiplexer Phases m MESS Pie USA un gt 5 6 A D Converter Simplified SECTION 6 Maintenance 61 Volts Calibration Configuration 300mV 6 2 DC VOlts Calibration Configuration 3V 300V Ranges 2 6 3 Four Wire Resistance Calibration Configuration 3000 30kQ Ranges
119. SSAGES Table 2 2 lists and explains the various display messages associated with front panel operation of the Model 199 Table 2 2 Error Messages E PROM failure on power up See paragraph 6 7 2 No shifted function Overrange Decimal point position and mnemonics define function and range 3kQ range shown The number of characters in the OVERFL message defines the display resolution 52d resolution shown Trigger received while still processing reading from last trigger Selecting dB with instru ment not in ACV or ACA Pressing a range button while in ACV dB or ACA dB Improper state when calibrating ie dB INTERVAL OVERRUN Interval too short NO DATA No data store data NO SCANNER Scanner not installed CAL LOCKED Calibration locked out CHAN 4 MAX Channel limit is 4 in 4 pole mode Channel limit is 8 in 2 pole mode TRIGGER OVERRUN AC ONLY NO RANGE CONFLICT CHAN 8 MAX With optional scanner BASIC DMM OPERATION 2 6 BASIC MEASUREMENTS The following paragraphs describe the basic procedures for making voltage resistance current and dB measure menis High Energy Circuit Safety Precautions To optimize safety when measuring voltage in high energy distribution circuits read and use the directions in the following warning WARNING Dangerous arcs of an explosive nature in a high energy circuit can cause severe personal injury or death If the meter is connected to a high
120. TFIT SETUPS OUTPUT F26 SETUPS SETUP L SETUPS second and third program statements define the two Translator words The two words combine to form the new word SETUP3 3 33 488 PROGRAMMING 3 10 5 Combining Translator Words With Keithley IEEE 488 Commands One or more existing Translator words including wild card words can be combined with Keithley IEEE commands resulting in a Translator word that contains the commands of the Translator words and the Keithley IEEE commands The format for combining Translator words with Keithley IEEE commands is shown in the following example ALIAS SETUP3 NEW SETUP1 NEW SETUP2 P1ZIX Where SETUP3 is the new Translator word SETUPI and SETUP2 are the existing words 21 is the Keithley IEEE command string NEW tells the instrument that SETUDP1 and SETUFP2 are Translator words When the Translator word SETUP3 is asserted over the bus the commands of the two Translator words and the Keithley IEEE command string will be executed Programming Example The following sequence will create two Translator words and then combine them with Keithley IEEEcommand string to form a new Translator word REMOTE FZ 726 ALIAS SETUP1F1X OUTPUT 726 amp LIAS SETUPS REX 7 7 OUTPUT 726 ALIAS SETUPS 1 SETUPS 21215 OUTPUT The s cond and third statements create two T
121. TY SYMBOLS AND TERMS 4 44 45 44 42 4 22 4 16 5 T 17 INSPECTION dives erm derer 18 USING THE MODEL 199 MANUAL Sado densa 19 GETTING STARTED E CNN cada aca HARE 110 ACCESSORIES wm hs et acad AER TE ile nr I vid s 2 PR OST 222 24 SUIT Le ee eee et ee We Ue SECTION 2 Basic DMM Operation 2 1 INTRODUCTION P S Sue 2 2 POWER UP PROCEDURE T ENTE Sones 2 2 1 Line Power PEE Salem Sth tese vus 2 2 2 Power Up Gass 2 23 Default Conditions 23 FRONT PANEL FAMILIARIZATION RTI METER 231 Display and Indicators M M 2 3 2 Power E HC 2 3 3 Controls Lr 2 34 CAL LOCK Switch 2 9 we duh e bE UT E 79 22 2 2 2 3 5 INPUT Switch dane TEE PEN 2 36 Current Input dase erra ae spass
122. U5 see schematic 199 116 shifts a digit enable bit to the next digit to be enabled Every 10 times the display is updated a digit enable it is generated at PA1 and goes to the data input of the shift register 1711 through 1712 are the drivers for the LED segments of the display digits and the LED indicators 5 7 POWER SUPPLIES The main power supplies of the Model 199 are located on sheet 5 of schematic drawing number 199 126 Fuse F2 is the line fuse which is accessible from the rear panel 52 is the POWER ON OFF switch and 53 selects 115V or 230V operation by placing the transformer primary windings in parallel or series The power transformer T1 has three secondary windings one for the 5V digital supply one for the 5V analog supply and one for the 15V analog supply CR13 CRM and CR15 provide fullwave rectifica tion for the three supplies while 050 through 053 pro vide the regulation Supply filtering is performed by C56 C60 C63 C65 and C72 5 8 SCANNER The optional Model 1992 Scanner Card allows the user to multiplex eight 2 pole inputs or four 4 pole inputs A schematic diagram of the Model 1992 is shown on draw ing number 1992 106 located at the end of Section 7 The main sections of the scanner card include the control and relay circuits as outlined below 5 8 1 Control Circuitry Control information for which channel should be closed is transmitted in via the STROBE DATA and CLOCK lines into U2
123. UDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE THE REMEDIES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES NEITHER KEITHLEY INSTRUMENTS INC NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT INDI RECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS INC HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES SUCH EXCLUDED DAMAGES SHALL INCLUDE BUT ARE NOT LIMITED TO COSTS OF REMOVAL AND INSTALLATION LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON OR DAMAGE TO PROPERTY KEITHLEY Test Instrumentation Group Keithley Instruments Inc 28775 Aurora Road Cleveland Ohio 44139 216 248 0400 Fax 216 248 6168 FRANCE Keithley Instruments SARL 3 All e des Garays 60 91121 Palaiseau C dex 01 60 11 51 55 Fax 01 60 11 77 26 GERMANY Keithley Instruments GmbH Landsberger Str 65 82110 Germering 089 849307 0 Fax 089 84930759 GREAT BRITAIN Keithley Instruments Ltd The Minster 58 Portman Road Reading Berkshire IEA 0734 575666 Fax 0734 596469 ITALY Keithley Instruments SRL Viale S Gimignano 38 20146 Milano 02 48303008 02 48302274 JAPAN Keithley Instruments Far East KK Sumiyoshi 24 Bldg Room 201 2 24 2 Sumiyoshi cho Naka ku Yokohama 231 81 45 201 2246 Fax 81 45 201 2247 NETHERLANDS
124. UP program the pole mode as re quired Also select the STEP or SCAN modes under the SCAN SETUP menu Return to normal display once all scanner setup programming has been completed 4 Using the SCANNER button program the desired channel limit 5 Press SHIFT store and then program the desired data store size in readings The number of readings equals the number channels per scan sequence times the number of scan sequences For example if the channel limit is 4 the data store size would be 32 with eight scan sequences 6 Press NEXT to exit the data store programming mode The STO indicator will flash on to indicate the unit is waiting for a trigger _ 7 Press TRIGGER to initiate the scan storage sequence One trigger per channel STEP or set of channels SCAN will be required to complete the sequence When all readings have been taken the RCL indicator will start flashing 8 Program a limit of 0 to exit the scan sequence The data can be recalled as outlined below Recalling Scanned Data To recall scanner data from data store simply press SHIFT RECALL to enter the recall mode Press NEXT to view the last location or key in the desired location number and then press the NEXT key to display the data which will also include the channel number in addition to the func tion except for ratio on channels 2 through 8 which displays ratio not function Use uprange or downrange to scroll through locations as required You can
125. URATION 8 channel 2 pole or 4 channel 4 CONTACT POTENTIAL lt 1zV per contact pair MAXIMUM SWITCHING RATE 40 channels second in cluding Model 199 4Y digit DCV reading time CONNECTOR TYPE Quick disconnect screw terminals 14 AWG maximum wire size MAXIMUM SIGNAL LEVEL 200V peak 100m4A resistive Joad CONTACT LIFE gt 10 operations at maximum signal level gt 10 operations cold switching CONTACT RESISTANCE lt 10 ISOLATION BETWEEN ANY TWO TERMINALS gt 100 75pF ISOLATION BETWEEN ANY TERMINAL AND EARTH 51090 lt 150 COMMON MODE VOLTAGE 350V peak between any ter minal and earth MAXIMUM VOLTAGE BETWEEN ANY TWO TERMINALS 200V peak MAXIMUM VOLTAGE BETWEEN ANY TERMINAL AND MODEL 3 INPUT LO 200V peak DIMENSIO WEIGHT 25mm high x 130mm wide x 170mm deez in X Sin x 6 in Adds 0 3kg 8 oz to Model 199 specifications subject to change without notice MAXIMUM READING RATES Readings Second Continuous External Trigger Triggered Via Into Memory Into Memory 488 Bus RESO MUX MUX MUX LUTION OFF ON OFF ON OFF 4 20 47 20 30 18 5 Digit 16 13 9 7 5 16 13 90 5 15 125 9 7 5 Reading rates are for fixed range readings with filters off for and 30mA ranges 5 2 digit rate is for 60Hz operation Values in parentheses 500 Reading Memory Stores reading range and scanner channel Tri
126. X is received is illegal IDDCO Set when an illegal device dependent command option IDDCO such as T9X is received 9 is illegal IEEE 488 PROGRAMMING The complete command string will be ignored if IDDC IDDCO no remote error occurs The U2 command lists the Translator words that have been defined by the operator The list will be transmitted only once each time the command is received The U3 command allows the user to find out the current defined size of the buffer The buffer size is controlled by the I command When this command is transmitted the instrument will transmit the value the next time it is ad dressed to talk This information will be transmitted only once each time the command is received The U3 value will not be cleared when read thus the U3 value is always current For example SZ 010 The U4 command sends the present value The value is a calibration value or zero value as programmed by the V command The US command sends a value that defines the status of the input switch A value of 0 indicates that the front panel input terminals are selected while a value of 1 indicates that the rear panel input terminals are selected For example RF 1 Progamming Example Enter the following statements in to the computer to obtain and display the machine status word U0 PROGRAM COMMENTS REMOTE 726 Send remote enable DIM Aslan 28 OUTPUT
127. addressing Secondary address byte values lie in the range of 60 7F Note however that many devices including the Mode 199 do not use secon dary addressing Once the device is properly addressed bus transmission sequences are set to take place For example if an instru ment is addressed to talk it will usually output its data string on the bus one byte at a time The listening device frequently the controller will then read this information as transmitted BUS LINES The signal lines on the IEEE 488 bus are grouped into three categories data lines management lines and handshake lines The eight data lines handie bus data and many com mands while the management and handshake lines en sure orderly bus operation Each bus line is active low with approximately zero volts representing logic 1 true The following paragraphs briefly describe the operation of these lines i Data Lines The bus uses eight data lines to transmit and receive data in bit parallel byte serial fashion These lines use the con vention DIOLDIO8 instead of the more common D0 D7 DIO1 is the least significant bit while DIO8 is the most significant bit The data lines are bidirectional with most devices and as with the remaining bus lines low is con sidered to be true Bus Management Lines The five bus management lines ensure proper interface control and management These lines are used to send uniline commands Attention
128. ading for each range is within the limits listed in the table 4 2 PERFORMANCE VERIFICATION Table 4 3 Limits for TRMS AC Volts Verification 199 Applied ACV Range AC Voltage to to to xk 284 100 to 295 900 2 84100 2 95900 28 4100 29 5900 284 100 295 900 289 365 to 290 635 2 89365 to 2 90635 28 9365 289 365 to 290 635 2 89365 to 2 90635 28 9365 to 29 0635 289 365 to 290 635 to 29 0635 289 365 to 290 635 Do not apply 290V at 100kHz to the input This exceeds the VeHz limit of the instrument Maximum TRMS AC volt input at 100kHz is 100V On the 300V range allowable readings with 100V 100kHz applied to the input are 98 200 to 101 800 See paragraph 2 6 7 for clarification of the VeHz specification MODEL 199 Power AC Voltage Ampliier Calibrator Model 5215A Model 52004 Figure 4 2 Connections for TRMS AC Volts Verification 4 5 3 Ohms Verification With the Model 199 set to 544d resolution verify the ohms function as follows CAUTION Do not exceed 425V peak or 300V RMS between the input HI and LO terminals or damage to the instrument may occur Select the ohms function and autorange Using Kelvin test leads such as the Keithley Model 1641 connect the resistance calibrator to the Model 199 as shown in Figure 4 3 Sett
129. ails 2 Use the N command as required to select the type of scanning operation To close individual channels simply send N followed by the appropriate channel number For step or scan use N10 through N18 or N20 through N28 as described in paragraph 3 12 1 3 If you wish to scan at programmed intervals select continuous trigger mode and then select the data store interval with the Q command For example send Q500X for a 500msec interval If you wish to trigger each chan nel separately select a one shot trigger mode This setup will require one trigger per channel or one trigger per set of channels depending on the scanner setup _ 4 Program the data store size with the I command Keep in mind that this value represents the total number of individual channels that will be stored For example if you select 400 and are scanning all eight channels the maximum number of data sets is 50 400 8 50 5 Trigger the instrument to begin the scanning sequence The trigger stimulus will depend on on the programmed trigger mode For example if you are using T2 or T3 send GET to trigger the instrument Also if you have pro grammed the one shot trigger mode it will be necessary to trigger the instrument for each channel step or set of channels scan Reading Scanned Data Once data has been scanned and stored it can be read back from the instrument over the bus One method to determine when the instrument is finished is to
130. al mode Use uprange or downrange to select the desired interval operation then press NEXT 4 For the select interval key in the desired scan interval in the range of 25msec and 999 9995 and press NEXT to complete programming 5 Press SHIFT SCAN SETUP and program the pole con figuration by pressing uprange or downrange 6 Press NEXT and then uprange or downrange until the step mode is selected as indicated by the following message STEP 7 Press NEXT and then select the desired ratio mode by using uprange or downrange B Press NEXT to complete scanner setup programming 9 Press SCANNER The unit will prompt you for the last channel in the scan sequence as follows LIMIT 10 Press the number key corresponding to the last chan 11 nel the sequence remember that the last channel is channel 4 for the 4 pole mode After the channel limit has been selected the instru ment will return to normal display and begin the scan sequence with channel 1 As each channel is scanned the unit will take a reading on that channel and display the results along with the selected channel number The sequence repeats until the last channel as determined by the programmed limit is scanned After the last channel the sequence starts over again with channel 1 stop scanning and return to normal display select a limit of 0 press SCANNER 0 NOTES 1 If an interval too short for the present
131. am and return to the 300mVDC range H Repeat the procedures in step 3 for the remaining DCV ranges using Table 6 5 as a guide Figure 6 2 shows connections for the 3V 300V ranges 4 For 488 bus calibration proceed as follows Set the DC voltage calibrator to output 0 300000V B After allowing sufficient time for the calibrator voltage to settle send the following commands over 777 the bus V 300E 3XC2X Set the calibration to 0 30000V D After allowing the calibrator voltage to settle send the following commands over the bus V300E 3XC1X MAINTENANCE E Set the DC voltage calibrator to output 0 00000V After allowing sufficient time for the calibrator voltage to settle send the following command over the bus VOXC1X All calibration constants will be automatically stored in E7PROM G Repeat steps A through D for the remaining DCV ranges using Table 6 5 as a guide DC Voltage Calibrator Model 5440A Divider Output LO MODEL 189 shielded Cable Figure 6 1 DC Volts Calibration Configuration 300mV Range DC Voltage Calibrator Model 5440A MODEL 199 Shietded Cable Figure 6 2 DC Volts Calibration Configuration 3V 300V Ranges 6 4 9 Resistance Calibration To calibrate the ohms function proceed as follows NOTE For front panel calibration omit step 4 of thefollowing procdure For IEEE 488 bus calibra tion omit step 3 Table 6 5
132. amples seks Nee EXTERNAL TRIGGERING e ce Gk oan eee aire External ETT Meter Complete a P zv 0 DATA 5 ea ET ew E eie s xiu ACE Storing Data at Programmed Intervals Dm Rocker IER Triggering One shot Readings into Data Store 2 25 Recalling Data eicere rm eret Eire aa UR dau stira SCANNER OPERATION oe OPTION N 1982 eer eee ee rere agent Scanner Connections he ete Scanner Display Format 222222222222 e ule ESI E P See Programming PPP M Ratio tues agit Reading interval obest doc qus Scan Limit vos ptu NIS ia VP QUA mini SURINAME p EE A S Manual Channel Mode Step Mode Operation H Scane Mode Operation Using Data Store with the Scanner rr iocus A Practical Scanner Application Amplifier Testing ee i
133. ange of the instrument is 6 06V to OV which is still 606000 counts Zero Correction The Model 199 must be properly zeroed when using the 300mV DC or the 3000 range in order to achieve rated accuracy specifications This procedure should be performed whenever the ambient temperature changes To use ZERO for zero correction perform the following steps 1 Disable zero if presently enabled by pressing the ZERO button The ZERO indicator will turn off 2 Select the 300mV DC or the 3000 range T 3 Connect the test leads to the input of the Model 199 and short them together If four wire resistance measurements are to be made connect and short all four leads together Allow any thermals to stabilize Note At 542 digit resolution low level measurement techniques need to be employed Use Kelvin test leads or shielded test leads See paragraph 2 6 5 for low level measurement considerations 4 Press the ZERO button The display will read zero 5 Remove the short and connect the test leads to the sig nal or resistance to be measured Note Test lead resistance 2 wire is also compensated for when zeroing the 3000 range with the above procedure Baseline Levels Baseline values can be established by ap plying baseline levels to the instrument To establish a baseline level by applying a level to the Model 199 per form the following steps 1 Disable zero if presently enabled by pressing the ZERO button The ZERO indi
134. bits in the error condition word and the serial poll byte error bit will be cleared when the word is read In addition SRQ operation will be restored after an error condition by reading U1 3 25 488 PROGRAMMING FACTORY DEFAULT 19 1 0 0 0 G 0 00 00 0 0 199 A B J MM NN 0 MODEL NUMBER PREFIX 199 AUTO CAL MULTIPLEX A O DISABLED 1 ENABLED READING MODE CONVERTER 1 STORE SINGLE READING 2 DATA STORE DUMP FUNCTION O DC VOLTS VOLTS 2 5 3 0C CURRENT 4 AC CURRENT 5 dB 6 ACA dB DATA FORMAT G O RDG WITH PREFIX 1 RDG WITHOUT PREFIX 2 RDG WITH PREFIXES AND BUFFER LOCATION 3 RDG WITHOUT PREFIX AND WITH BUFFER LOCATION 4 RDG WITH PREFIXES AND CHANNEL S RDG WITHOUT PREFIXES AND WITH CHANNEL 6 RDG WITH PREFIX BUFFER LOCATION AND CHANNEL 723RDG WITHOUT PREFIX WITH BUFFER LOCATION AND CHANNEL SELFTEST J O INACTIVE 1 RAM and PASSED 2zE PROM FAILED EO BUS HOLD OFF O EOI AND HOLD OFF 1 NO EO AND HOLD OFF 2 AND NO HOLD OFF 3 NO AND HOLD OFF SRQ M MOO DISABLED MO1 READING OVERFLOW MO2 DATA STORE FULL 04 STORE HALF FULL MOB READING DONE M16 READY M32 xERROR SCANNER N NO CHANNELS OPEN N1 N8 CHANNEL CLOSED NiQ STEP OPEN Ni1 N18 STEP LIMIT N20 SCAN OPEN N2i N28 SCAN LIMIT POLE RATIO 022 POLE 1 4 POLE 2 2 POLE RATIO 3 4 POLE RATIO 000000 4 1 6 w
135. bration switch in the disable position Channel limit is 4 in 4 pole mode Channel limit is 8 in ee mode AEN IDDC IDDCO TRIGGER OVERRUN INTERVAL OVERRUN BIG STRING CAL LOCKED CHAN 4 MAX CHAN 8 MAX Scanner error messages See paragraph 3 12 NOTE Error messages associated with translator software are located in paragraph 3 10 No Remote Error no remote error will occur if the instrument receives a device dependent command and the REN Remote Enable line is false In this instance the following error message will be displayed on the front panel NO REMOTE The error condition can be corrected by placing the REN line true before attempting to program the instrument Programming Example To demonstrate the NO REMOTE error message type in the following lines LOCAL OUTPUT 726 5 Note that the REMOTE error message is briefly displayed when the second statement above is executed IDDC Illegal Device Dependent Command Error An IDDC error occurs when the unit receives an invalid command over the bus For example the command string 1 includes an illegal command because the letter E is not part of the instrument s programming language When an illegal command is received the instrument will brief ly display the following error message IDDC x z To avoid this error condition send only valid commands Refer to paragraph 3 9 for device dependent command pro gramming detail
136. bus ATN is true when these commands are asserted UNL Unlisten Listeners are placed in the listener idle state by UNL UNT Untalk Any previously commanded talkers will be placed in the talker idle state by Device Dependent Commands The purpose of device dependent commands will depend on instrument configuration Generally these commands APPENDIX C are sent as one or more ASCII characters that command the device to perform a specific action For example the command string ROX is used to control the measurement range of the Model 199 The IEEE 488 bus treats these commands as data in that AIN is false when the commands are transmitted Command Codes Command codes for the various commands that use the data lines are summarized in Figure C 3 Hexadecimal and and decimal values for the various commands are listed in Table C 2 APPENDIX SECONDARY COMMAND GROUP 500 PRIMARY ADDRESS 5356 5 EB COMMAND UNIVERSAL COMMAND GROUP ADDRESSED COMMAND Dy DIOR PPE PARALLEL POLL CONFIGURE PPU PARALLEL POLI UNCONFIGURE AND X DONT 8 TCT TAKE CONTROL NOT IMPLEMENTED BY MODEL 199 NOTE Dy DIOL Figure C 3 Command Codes 6 Table 2 Hexadecimal and Decimal Command Codes Decimal Value _ Typical Command Sequences For the various multiline commands a specific bus se
137. calibration 6 4 8 DC Volts Calibration To calibrate the DCV function proceed as follows NOTE For front panel calibration omit step 4 of the following procedure For IEEE 488 bus calibration omit step 3 1 Select the DC VOLTS function and the 300mV range 2 Connect the DC calibrator to the instrument as shown in Figure 6 1 300mV range only use Figure 6 2 for 3V 300V ranges NOTE Low level measurement techniques should be used when calibrating the 300mV DC range Refer to paragraph 2 6 5 for low level measurement con siderations 3 For front panel calibration press SHIFT LOCAL and proceed as follows A With the 300 000mV DC calibration point displayed on the Model 199 set the DC calibrator to output 0 300000V After allowing sufficient time for the calibrator voltage to settle press the NEXT button The follow ing message will be displayed for several seconds WORKING C With the 300 000mV DC calibration point displayed set the DC calibrator output to 0 30000V D After allowing the voltage to settle press NEXT The following message will be displayed WORKING E With the 000 000mV DC calibration point displayed set the DC calibrator to output 0 000000V After allowing sufficient time for the calibrator voltage to settle press the NEXT button The follow ing message will be displayed for several seconds WORKING G The instrument will exit the calibration progr
138. canner Card Model 1998 Rack Mounting Kit The Model 1998 1 Single Fixed Rack Mounting Kit mounts a single Model 199 in a Sst ndard 19 inch rack The Model 1998 2 Dual Fixed Rack Mounting Kit mounts two Model 199s side by side in a standard 19 inch rack Model 5806 Kelvin Clip Lead Set The Model 5806 includes two Kelvin clip test lead assemblies with banana plug ter mination one red one black A set of eight replacement rubber bands for the Model 5806 is also available Keithley PIN 22 Model 7007 488 Shielded Cables The Model 7007 connects the Model 199 to the IEEE 488 bus using shield ed cables to reduce electromagnetic interference EMI The Model 7007 1 is one meter in length and has EMI shield ed 488 connector at each end The Model 7007 2 is identical to the Model 7007 1 but is two meters in length Model 7008 IEEE 488 Cables The Model 7008 connects the Model 199 to the IEEE 488 bus The Model 7008 3 is 0 9m 3 ft in length and has a standard IEEE 488 connector at each end The Model 7008 6 cable is identical to the Model 7008 3 but is 1 8m 6 ft in length 1 3 1 4 SECTION 2 Basic DMM Operation 2 1 INTRODUCTION Operation of the Model 199 can be divided into two general categories front panel operation and IEEE 488 bus opera tion This section contains information necessary to use the instrument from the front panel These functions can also be progra
139. cator will turn off 2 Select a function and range that is appropriate for the anticipated measurement 3 Connect the desired baseline level to the input of the Model 199 and note that level on the display 4 Press the ZERO button The display will zero and the ZERO indicator wil be enabled The previously displayed reading will be the stored baseline WARNING With ZERO enabled a hazardous voltage baseline level 40 or more not displayed may be present on the input terminals not sure what is applied to the input assume that a hazardous voltage is present 5 Disconnect the stored signal from the input and con nect the signal to be measured in its place Subsequent readings will be the difference between the stored value and the applied signal Notes 1 Disabling zero cancels the zero baseline value on that selected function Baselines established on other func tions are not affected 2 store a new baseline on a selected function zero must first be disabled and then enabled again The new value will be stored with the first triggered conversion 3 Setting the range lower than the suppressed value will overrange the display the instrument will display the overflow message under these conditions 4 When the ZERO button is pressed to enable zero the ZERO indicator light will blink until an on scale reading is available to use as a zero level In the one shot trig ger mode the unit must be triggered to stor
140. ck is fed through 016 back to the integrator input The final slope comparator output is then gated with the 3 84MHz clock and counted Once the comparator output goes low the VIA stops counting and the reading can be computed PRINCIPLES OF OPERATION A D Counts Output Final Charge Slope Balance Current Current U5B Duty Cycle Comparator Figure 5 6 A D Converter Simplified Schematic U7 U6 U44 Feedback Control Circuit PRINCIPLES OF OPERATION 5 5 CONTROL CIRCUITRY The signals for the circuitry that provides control of the various FETs relays analog switches and logic levels are supplied by the shift store registers U29 U30 U31 and U32 see schematic 199 126 page 3 CLOCK DATA and STROBE signals are sent from the VIA U8 across the opto isolators ATI AT2 and AT3 see schematic 199 126 page 5 The isolators provide 500 isolation between the analog and digital sections of the instrument DATA is serially loaded into the shift store registers and a STROBE pulse causes the registers to simultaneously output the ap propriate logic levels to the FET analog switch and relay drivers 5 6 DIGITAL CIRCUITRY The Model 199 is controlled by an internal microcomputer This section briefly describes the operation of the microcomputer and associated digital circuitry Refer to schematic diagram number 199 106 for circuit details 5 6 1 Microcomputer The microcomputer centers around 8 bit 6880
141. configuration is selected the instrument will display the INTERVAL OVERRUN message The instrument will continue to step through channels but it will not be able to scan the channels at the programmed intervals The filter status resolution and selected function affects the overall reading rate and thus the minimum interval that can be used The CHAN 4 MAX message will be displayed if you attempt to program a channel limit greater than four in the 4 pole mode One shot Triggering Use the general procedure below to use one shot trigger ing to scan channels in the step mode 10 1 12 Select the function and range as required for the ex pected measurement Press SHIFT TRIG SETUP and select the one shot trig ger mode If a circuit settling time for each channel is required program a trigger delay under the TRIG SETUP menu Return to normal display by pressing NEXT as necessary Press SHIFT SCAN SETUP and program the pole configuration Press NEXT and select the step mode with uprange or downrange Press NEXT and program the ratio mode as required Press NEXT to return to normal display Press SCANNER and program the channel limit at the prompt Keep in mind that the maximum channel limit is 4 in the 4 pole mode Press TRIGGER or apply an external trigger pulse to close channel 1 and take a reading on that channel The reading and channel numbe
142. ction and range suitable for the applied signal 7 Press TRIGGER to initiate readings Note that the display updates at a rate of once every 312 seconds as shown by the following decimal point Example 2 One shot trigger mode with a one second trig ger delay 1 Press SHIFT TRIG SETUP and then uprange or downrange if necessary so the unit displays the following ONE SHOT 2 Press NEXT to advance to the delay time selection 3 Press 0 0 1 0 0 0 to program one second delay 4 Press NEXT to return to normal display 5 Connect a time varying signal and select an appropriate range and function 6 Press TRIGGER to initiate a single reading Note that the display updates once after a delay of approximately one second 7 Press TRIGGER a number of times and note that one reading per trigger is processed with a one second in terval between triggers and readings The trigger status LED flashing decimal point indicates the display update 2 9 EXTERNAL TRIGGERING Th Model 199 has two external BNC connectors on the rear panel associated with instrument triggering The EX TERNAL TRIGGER INPUT connector allows the instru ment to be triggered by other devices while the METER COMPLETE OUTPUT connector allows the instrument to Triggers on Leading Edge lt 0 ous Minimum Figure 2 8 External Trigger Pulse Specifications To use the external trigger proceed as follows 1 Connect the external trig
143. current through R1 and R4 Thus the voltage seen by the instrument is much closer to the actual value across the measured xesistance minimizing the error DC Amps and AC Amps The resistor current shunt network R75 and R30 is con figured so that a full scale current input will result in a 300mV drop across the network on both current ranges For 30mA DC this voltage is routed to the multiplexer through U23C and U22B For 3A DC this voltage is routed to the multiplexer through Q37 and U22B For AC Amps the signal is routed through U23D to X10 amplifier U28B The amplified signal then travels through analog switch U23B and buffer U26B to the TRMS converter The con verted DC signal is then routed to the multiplexer PRINCIPLES OF OPERATION Front Panel Ref Hi Input R1 Hi Sense R2 q HI Sense LO Reet VQ Sense HI VQ Sense LO VQ Ref HI VO Ref LO Rx Figure 5 2 Input Configuration During 2 and 4 Terminal Resistance Measurement PRINCIPLES OF OPERATION 5VR 2 Ref HI To Q35 of Q12 2 Multiplexer Reference R17A R17B Resistors 1 411MQ Q Ref LO To U24C of 30kQ Multiplexer Q Ref LO To U24D of 300Q 3kQ Multiplexer 29 U22c lt Ref LO To Q34 of 300kQ 300MQ Multiplexer To Q30 of Multiplexer Q Sense Sense LO To U24B of Multiplexer VO Sense HI VO Sense LO Rx VQ Ref HI Ref LO
144. curs at the end of a software generated delay period that allows the signal to settle after the appropriate multiplexer FET is turned on Once the input is enabled the signal from the buffer amplifier is added to the level shift current applied through R62C and R61 or R61 only In this manner the 3 03V bipolar signal from the buffer amplifier is converted to a unipolar signal that can be integrated The integrator is up of Q1 U19 and C32 When the input to the integrator is applied the integrator output ramps up until its voltage is slightly higher than the voltage applied to the inverting input of the duty cycle comparator U5A The charge balance current whose duty cycle is _ proportional to the input is fed back to the integrator in put through R8 and Q4 Since the charge balance current is much larger than the sum of the input and level shift currents the integrator output now ramps in the negative direction until Q of U8B goes low The VIA located in the microcomputer then counts the total number of pulses that occur during the charge balance phase At the end of the charge balance phase the output of the integrator is resting at some positive voltage Since the in tegrator output is connected to the non inverting input of the final slope comparator U5B the final slope com parator output remains high until the integrator output ramps in the negative direction During final slope Q4 is turned off and the feedba
145. cuted the Model 199 is serial polled and the decimal value of the serial poll byte is displayed on the computer CRT 3 9 DEVICE DEPENDENT COMMAND PROGRAMMING TEEE 488 device dependent commands are used with the Model 199 to control various operating modes such as function range trigger mode and data format Each com mand is made up of a single ASCII letter followed by a number representing an option of that command For ex ample a command to control the measuring function is programmed by sending an ASCII F followed by number representing the function option A number of commands may be grouped together in one string A command string is usually terminated with an ASCII X character which tells the instrument to execute _ the command string Commands sent without the execute character will not be executed at that time but they will be retained within an internal command buffer for execu tion at the time the X character is received If any errors occur the instrument will display appropriate front panel error messages and generate an SRQ if programmed to do 50 Commands that affect instrument operation will trigger a reading when the command is executed These bus com mands affect the Mode 199 much like the front panel con trols Note that commands are not necessarily executed the order received instead they will be executed in alphabetical order Thus to force a particular command se quence you w
146. d the RCL will start flashing and STO will turn off to indicate that the storage process has been completed except for con tinuous storage NOTES 1 Once data storage is initiated data store can be disabled by pressing any function key VOLTS OHMS eic Do ing so will select that function However if recall is also enabled first press NEXT then the desired function key to disable data store 2 Autoranging can be used with data store but it must be selected before entering data store 3 The front panel INTERVAL OVERRUN message in dicates that the programmed data store interval is too short for the present instrument configuration Although the instrument will continue to store readings as fast as it can storage will not occur at the programm ed interval under these conditions 4 Enabling data store clears the buffer of previously stored readings 5 If a data store size larger than 500 readings is pro grammed the following message will be displayed MAX 500 MPG 2 10 2 Triggering One shot Readings into Data Store Reading storage can be controlled by trigger pulses applied to rear panel EXTERNAL TRIGGER INPUT paragraph 2 9 or by using the front panel TRIGGER button as described below The procedure below assumes that the default trigger source has not been altered by FOU the instrument over the IEEE 488 bus 1 Select the function and range to be used to make the measurements aut
147. d for several seconds WORKING C With the 00 0000mA DC calibration point displayed set the current calibrator to output 00 0000mA D After allowing sufficient time for the measurement to settle press the NEXT button The following message will be displayed for several seconds WORKING E The instrument will exit the calibration program and return to the 30mA range F Repeat the procedures in step 3 for the 3A DC range using Table 6 8 as a guide 4 For IEEE 488 bus calibration proceed as follows Set the current calibrator to output 30 0000mA B After allowing sufficient time for the calibrator cur rent to settle send the following command over the bus V30E 3XCOX C Set the current calibrator to output 00 0000mA D After allowing sufficient time for the calibrator cur rent to settle send the following command over the bus VOXCIX Both calibration constants will automatically be stored in E7PROM E Repeat steps A through D for the remaining DCA range using Table 6 8 as a guide Table 6 8 DC Current Calibration 399 DC Current 199 DCA Calibration Calibrator IEEE 488 Range Point Output Bus Commands V30E 3XCOX VOXCIX V3XC1X VOXCIX 30 0000mA 00 0000mA 3000 00mA 0000 00mA 30mA 30 0000mA DC Voltage Calibrator Calibrator Model 2500E Model 5440A Figure 6 8 DC Current Calibration Configuration 6 4 12 TRMS AC Current Calibration Perform the following procedure to calibrate the AC
148. d sets the bus error bit in its status byte The computer then serial polls the instru ment line 40 and then displays the status byte bits in proper order on the CRT In this example the 5 B6 and error B5 bits are set because of the attempt to pro gram an illegal command option K5 Other bits may also be set depending on instrument status 3 9 14 and Bus Hold off Modes K The K command allows control over whether or not the instrument sends the EO command at the end of its data string and whether or not bus activity is held off through the NRFD line until all commands sent to the instrument are internally processed once the instrument receives the X character K command options include KO Send EOI with last byte hold off bus until com mands processed on X Do not send EOI with last byte hold off bus until commands processed on X 2 Send EOI with last byte do not hold off bus on X Send no EOI with last byte do not hold off bus on X or SDC command the instrument will return to KO The line on the IEEE 488 bus provides a method to positively identify the last byte in a multi byte transfer se quence Keep in mind that some controllers rely on EOI to terminate their input sequences In this case suppress ing EOI with the K command may cause the controller in put sequence to hang unless other terminator sequences are used bus hold off mode allows the instrume
149. ded power source See paragraph 2 2 1 for more complete information 2 Press in the POWER switch to apply power to the in strument The instrument will power up in the 300V DC range Making Measurements 1 Connect the supplied safety shrouded test leads to the front panel VOLTS HI and LO input terminals Make sure the INPUT switch on the front panel is in the front position 2 make a voltage measurement simply connect the in put leads to a DC voltage source up to 300V and take the reading from the display 3 To change to a different measuring function simply press the desired function button For example to measure resistance press the OHMS button Using DMM Setup Press SHIFT DMM SETUP then use NEXT to scroll through selections The following can be selected or viewed Software revision Mux on off _ IEEE 488 address Line frequency Save setup LED test Diagnostics Unit reset r2 GENERAL INFORMATION For all selections except software revision and IEEE 488 ad dress use uprange downrange to toggle the selection Paragraph 2 7 provides the detailed information for using DMM SETUP 1 10 ACCESSORIES The following accessories are available to enhance Model 199 capabilities Model 1651 50 Ampere Current Shunt The Model 1651 is an external 0 0010 1 4 terminal shunt which permits current measurements from 0 to 50A AC or DC Model 1681 Clip On Test Lead Set
150. del 199 Typical connections for this arrangement are shown in Figure 2 17 Here the scanner card outputs are connected to the Model 181 mV input using low thermal cables Likewise all scanner inputs must be made with low thermal cables Use copper wire and keep all connections clean and free of oxidation Also all signal paths should be shielded as discussed above 2 37 BASIC DMM OPERATION 2 11 4 Scanner Delay channel settling time can be incorporated by program ming the scanner delay with the TRIG SETUP key When a scanner delay is used the instrument will wait the pro grammed delay period after closing a channel before tak ing a reading Thus the delay period is essentially a chan nel settling time to allow signals to settle before each measurement The scanner delay settling time in the range of Omsec to 999 9995 can be programmed using TRIG SETUP follows 1 Press TRIG SETUP and then NEXT and note that the instrument displays the following DELAY Followed by 000 000 S 2 Key in the desired delay period in the range of 0 t 999 99sec 3 Press NEXT once to advance to the interval selection menu or press NEXT twice to return to normal display NOTES 2 1 A scanner delay of at least one second should be used when measuring AC signals This recommendation is based on allowing the measurement to settle to within 0 1 of the final value 2 The programmed interval mus
151. ding will be triggered when the statement is executed IEEE 488 PROGRAMMING 3 8 8 Serial Polling SPE SPD The serial polling sequence is used to obtain the Model 199 serial poll byte The serial poll byte contains impor tant information about internal functions as described in paragraph 3 9 13 The serial polling sequence can also be used by the controller to determine which instrument on the bus has asserted SRQ Service Request The serial polling sequence is generally conducted as follows 1 The controller sets ATN true 2 The controller then places the SPE Serial Poll Enable command byte on the data bus At this point all active devices are in the serial poll enabled mode and waiting to be addressed 3 The Model 199 is then addressed to talk 4 The controller sets ATN false 5 The instrument places its serial poll bite on the data bus to be read by the controller 6 The controller then sets ATN true and places the SPD Serial Poll Disable command byte on the data bus to end the serial polling sequence Once instruments are in the serial poll mode steps 3 through 5 above can be repeated by sending the correct talk address for each instrument Programming Example The SPOLL statement automatically performs the sequence just described To demonstrate serial polling type in the following program lines 18 REMOTE 726 SH Ss SPOLL 7262 PRINT 48 When the above program is exe
152. dless of the in strument Commands supported by the Model 199 are summiarized in Table 3 6 which lists BASIC 4 0 statements necessary to send each command Note that commands requiring a primary address assume that the Model 199 primary address 15 set to 26 its factory default address 3 8 1 REN Remote Enable REN is a uniline command that must be asserted by the controller to place the Model 199 in remote Simply set ting REN true will not actually place the instrument in remote instead the unit must be addressed to listen after REN is set true Generally remote enable should be asserted before at tempting to program the instrument over the bus Once the instrument is in remote all front panel controls except LOCAL will be inoperative Normal front panel operation can be restored by pressing the LOCAL key place the Model 199 in remote the controller must per form the following sequence 1 Set the REN line true 2 Address the Model 199 to listen Programming Example Place the Model 199 in remote with the following statement REMOTE TEE The Model 199 should be in remote as indicated by the annunciator light If not check to see that proper bus con nections are made and that the instrument is programm ed for the correct primary address 26 Note that all front panel controls except LOCAL and of course POWER inoperative while the instrument 15 in remote You can restore normal fr
153. e Model 199 WARNING Do not exceed 30V between the METER COM PLETE common outer ring and chassis ground to avoid a shock hazard and possible in strument damage 2 Select the desired function range trigger mode and other operating parameters as desired 3 In a continuous trigger mode the instrument will out put pulses at the conversion rate each pulse will occur after the Model 199 has completed a conversion 4 n a one shot trigger mode the Model 199 will output a pulse once each time it completes a reading after be ing triggered Reading Done Begin Next Conversion Y LS TTL High 3 4V Typical LS TTL Low 0 25V Typical 4 10us gt Minimum Figure 2 9 Meter Complete Pulse Specifications 2 10 DATA STORE _ Data Store can store up to 500 readings for later recall Data can be stored at specified intervals of between 15msec and 999 999sec with 1msec increments In addition one shot external or front panel triggering can be used to store data at user defined rates The following paragraphs describe front panel operating procedures for storing and recalling data 2 10 1 Storing Data at Programmed Intervals Use the following procedure for storing data at defined intervals 1 Select the function and range to be used to make measurements 2 Press SHIFT TRIG SETUP and verify that the con tinuous trigger mode is selected as follows CONTINUOUS 3 If necessary press uprange
154. e addressed device responds Generally instruments return to their power up default conditions when respon ding to SDC Go To Local GTL is used to remove instruments from the remote mode and place them in local With many instruments GTL may also restore operation of front panel controls if previously locked out GET Group Execute Trigger GET is used to trigger devices to perform a specific action that will depend on device configuration for example perform a measurement sequence Although GET is an addressed command many devices may respond to GET without addressing Address Commands Addressed commands include two primary command groups and a secondary address group is true when these commands are asserted These commands include LAG Listen Address Group These listen commands are derived from an instrument s primary address and are used to address devices to listen The actual command byte is obtained by ORing the primary address with 20 TAG Talk Address Group The talk commands are de rived from the primary address by ORing the address with 40 Talk commands are used to address devices to talk SCG Secondary Command Group Commands in this group provide additional addressing capabilities Many devices including the Model 199 do not use these commands Unaddress Commands The two unaddress commands are used by the controller to remove any talkers or listeners from the
155. e instrument has been subjected to extremes of temperature or humidity allow at least one additional hour for the instrument to stabilize before beginning the calibration procedure 6 4 4 CAL LOCK Switch Upon power up calibration is automatically locked out A CAL LOCK switch accessible from the front panel disables or enables front panel and IEEE 488 bus calibra tion When calibration is disabled calibration cannot be performed The following message will be briefly displayed when attempting to enter the calibration program while the switch is disabled CAL LOCKED Calibration can only be accomplished with calibration enabled enable calibration push in on the CAL LOCK switch with an insulated tool through the small access hole under the round label The instrument will briefly display the following message CAL UNLOCK 30mA ranges 0 025 After calibration is complete press in on CAL LOCK a se cond time in order to disable calibration The unit will then display the CAL LOCKED message NOTE The two decimal points in the function area of the display will be on when calibration is enabled 6 4 5 Front Panel Calibration The following information provides the basic procedure for calibrating the instrument from the front panel A detailed calibration procedure is located in paragraph 64 NOTE DCV ranges have three cal points minus full range plus full range and zero The remaining function
156. e that all commands in the previous string were vali Programming Example Enter the statements to the keyboard The X character will be transmitted to the instrument No mode changes will occur with this example because no other commands were sent Note that the instrument re mains in the listener active state after the command is transmitted 3 9 2 Function F The function command allows the user to select the type of measurement made by the Model 199 When the instru ment responds to a function command it will be ready to take a reading once the front end is set up The func tion may be programmed by sending one of the following commands DC Volts Fi AC Volts F2 Ohms F3 DC Current F4 AC Current F5 ACV dB F6 ACA dB Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition Programming Example Place the instrument in the ohms function by pressing the OHMS button and enter the following statements into the computer keyboard REMOTE ree OUTPUT F ax When FOX is executed the instrument changes to DC volts 3 9 3 Range R The range command gives the user control over the sen sitivity of the instrument This command and its options perform essentially the same functions as the front panel Range buttons Range command parameters and the respective ranges for each measuring function are sum
157. e the zero value BASIC DMM OPERATION 2 6 3 Filter and Resolution The following paragraphs discuss the internal running average filter and the 4 and 5 digit resolution modes of the Model 199 Filter The Model 199 uses two running average filters in order to reduce reading noise The two filters include the inter nal filter and the front panel filter as described below When the front panel FLTR light is off the internal filter is enabled and the number of integrations per reading averaged depends on the selected range and function as indicated below fIntegrations Window Averaged Function Range Counts Per Reading DCV 300mV 6 1i DCV 3V 300V 3 6 ACV All None None Ohms 3000 30kQ 4 6 Ohms 300kQ 10 11 Ohms 3MQ 40 1 Ohms 30MQ 300MQ 400 31 T DCA All 6 1 None None dBA None None In order to speed up response to large signal steps changes the Model 199 uses a window around the displayed average As long as the readings are within this window the displayed value is based on the average of the most _ recent number of integrations If a new integration is out side this window the displayed value will be the new reading and new averaging will start from this point The window value for the internal filter also depends on the range and function see above The front panel filter is enabled when the front panel FLTR indicator is on The front panel f
158. ect to extremes of temperature outside the range specified in paragraph 4 2 additional time should be allowed for internal temperatures to reach normal operating temperature Typically it takes one additional hour to stabilize a unit that is 10 C 18 F outside the specified temperature range 4 4 RECOMMENDED TEST EQUIPMENT Table 4 1 lists all test equipment required for verification Alternate equipment may be used as long as the substitute equipment has specifications at least as good as those listed in the table NOTE The verification limits in this section do not include test equipment tolerance and are based on one year accuracy specifications Table 4 1 Recommended Test Equipment Fluke Fluke DC Voltage Calibrator AC Voltage Calibrator Fluke AC Power Amplifier Fluke Resistance Calibrator Valhalla AC DC Current Calibrator 300mV 30V 300V ranges 15 300mV 3V 30V ranges 2082 0 1 50Hiz 20kHz 0 02 100kHz 20 3396 300 range 20Hz 0 12 50Hz 20kHz 10 0496 100kHz 0 1 3000 ranges 15ppm 32ppm 300MQ range 225 30mA ranges 0 03 DC 0 1 to 5kHz at full scale output PERFORMANCE VERIFICATION 4 5 VERIFICATION PROCEDURES The following paragraphs contain procedures for verify ing the one year accuracy specifications of the instrument at 544d resolution for each of the five measuring functions
159. eference dBW measurements are made in the same manner as dBm measurements that is calculate the voltage reference for a particular impedance and set the instrument to it with the dB program The only difference between dBm and dBW is the reference point ImW vs IW The following equation can be used to calculate the voltage reference For 0dBW VIW Z BASIC OPERATION Table 2 4 Corresponding Voltage Reference Levels for impedance References Reference Voltage Level for OdBW Reference Impedance 0 V for 0 We2per V 7 Vie for 0dBW 2 6 10 TRMS Considerations Most DMMs actually measure the average value of an in put waveform but are calibrated to read its RMS equivalent This poses no problems as long as the waveform being measured is a pure low distortion sine wave For complex nonsinusodial waveforms however measurements made with an averaging type meter can be grossly inaccurate Because of its TRMS measuring capabilities the Model 199 provides accurate AC measurements for a wide variety of AC input waveforms TRMS Measurement Comparison The RMS value of a pure sine wave is equal to 0 707 times its peak value The average value of such a waveform is 0 637 times the peak value Thus for an average responding meter a correction factor must be designed in This correction factor K can be found by dividing the RMS valued by the average value as fol
160. efine input from IEEE 488 bus SB PRINT Enable remote PRINT HT 8 be Address 199 to listen send string PTA PRIHT ELFI Line feed on PRIHT RDZ SZEISIHPUTSS 1 Address 199 to talk input data PRINT Untalk the 199 Lat FERE Define output to CRT 118 18488 Define input from keyboard 128 PRINT _ Display reading string 158 GOTO 28 Repeat NOTES 1 If conversion to numeric variable is required make the following changes 128 Ss 1272 125 2 The Apple II terminates on commas in the data string To avoid problems program the Model 199 for the or 1 data format to eliminate commas APPENDIX B HEWLETT PACKARD MODEL 85 The following program sends a command string to the Model 199 from an HP 85 computer and displays the instrument reading string on the computer CRT The computer must be equipped with the HP82937 GPIB Interface and an ROM DIRECTIONS 1 From the front panel set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the HP82937A GPIB interface installed in the HP 85 computer 3 Enter the lines in the program below using the END LINE key after each line 4 Press the HP 85 RUN key and type in the desired command string at the command prompt For example to place the instrument in ACV and autorange type in FIROX and press the END LINE key
161. ements 2 12 BASIC DMM OPERATION 2 6 9 dB Measurements The dB measurement mode makes it possible to compress a large range of measurements into a much smaller scope AC dB measurements can be made with the instrument in the ACV or ACA function The relationship between dB and voltage and current can be expressed by the follow ing equations Vin 20 log V ves 20 log gt ref In ACV the instrument will read OdB when 1V is applied to the input With ACA dB selected the instrument will read 0dB when ImA is applied to the input M dB dB Reference levels other than and 1mA cannot be directly programmed but they can be established with the zero feature This procedure simply consists of applying a signal to the instrument and pressing the ZERO button That suppressed level is the dB reference 048 point The following procedure explains how to use the zero feature to establish a reference 1 Apply a voltage or current signal that is to be used as the dB reference to the input of the Model 199 2 Press the ZERO button The ZERO indicator will turn on and the display will zero The reference is now whatever the applied signal is 3 Disconnect the signal from the instrament AC dB Measurements Perform the following steps to make dB measurements 1 Select the AC volts or AC amps function Press or AMPS then AC 2 Select the front or rear panel input t
162. ent Dur ing the delay period the input multiplexing FETs are switched on so the instrument is set to begin integration upon conclusion of the programmed delay period A delay period can be programmed using the following command Wn Here n represents the delay value in milliseconds The range of programmable delay values is from Omsec to 999999msec IEEE 488 PROGRAMMING Examples For a delay of 0 002sec send W2X For a delay of 30 05sec send W30050X For a delay of 60sec send W60000X Upon power up or after receiving a DCL or SDC com mand the instrument will return to the default condition Programming Example Io program a 250msec delay period into the instrument enter the following statements into the computer REMOTE TZS OUTPUT 26 The instrument will wait for 250 after each triggered conversion before executing the next conversion period 3 9 19 Self Test J The J command causes the instrument to perform tests it automatically performs upon power up When the self test command is given the Model 199 performs the following tests 1 ROM Test 2 RAM Test 3 EPROM Test J command parameters include JO Perform self test If the self test is successful the J byte in the U0 status word will be set to 1 If E7PROM fails the message UNCAL will be displayed and the J byte in the U1 status word will be set to 2 An E PROM failure is also flagged in the U1 status w
163. enter the following statements into the computer CUTPUT 725 1701511893172 TRIGGER FZS I The instrument will start storing readings in the buffer However since the instrument cannot make measurements at the selected interval 15msec interval overrun errors will occur 3 7 2 IEEE 488 REMOTE indicator and LOCAL Key REMOTE The REM indicator shows when the instrument isin the remote mode Note that REM does not necessarily indicate the state of the REN line as the instrument must be addressed to listen with REN true before the REM in dicator will tarn on When the instrument is in remote all front panel keys except for the LOCAL key will be lock ed out When REM is turned off the instrument is in the local mode LOCAL The LOCAL key cancels the remote mode and restores local operation of the instrument Since all front panel keys except LOCAL are locked out when the instrument is in remote this key provides a con venient method of restoring front panel operation Press ing LOCAL will also turn off the REM indicator and return the display to the normal mode if user messages were previously displayed with the D command Note that the LOCAL key will also be inoperative if the LLO Local Lockout command is in effect 488 PROGRAMMING 3 8 GENERAL BUS COMMAND PROGRAMMING General bus commands are those commands such as DCL that have the same general purpose regar
164. ential may be present on the terminal s Standard safe ty practices should be observed when such dangerous levels are encountered The WARNING used in this manual explains dangers that could result in personal injury or death The CAUTION used in this manual explains hazards that could damage the instrument GENERAL INFORMATION 1 6 SPECIFICATIONS Detailed Model 199 specifications may be found preceding the Table of Contents of this manual 1 7 INSPECTION The Model 199 System DMM was carefully inspected both electrically and mechanically before shipment After un packing all items from the shipping carton check for any obvious signs of physical damage that may have occurred during transit Report any damage to the shipping agent Retain and use the original packing materials in case reshipment is necessary The following items are shipped with every Model 199 order Model 199 System DMM Model 199 Instruction Manual Safety shrouded test leads Model 1751 Additional accessories as ordered VNPT If an additional instruction manual is required order the manual package Keithley Part Number 199 901 00 The manual package includes an instruction manual and any applicable addenda 1 8 USING THE MODEL 199 MANUAL This manual contains information necessary for operating and servicing the Model 199 System DMM The informa tion is divided into the following sections Section 1 contains general information
165. er val will then be displayed as in this example INTERVAL 000 175 5 Here we have assumed the default interval of 175msec 4 desired key in a new reading interval in the range of 15msec to 999 999sec 5 Once the desired interval is displayed press NEXT to return to normal display If you progam too small an interval the following will be displayed MIN 0155 2 20 BASIC DMM OPERATION 2 8 5 Trigger Programming Examples Example 1 Continuous with 3 5sec intervals between readings 1 Press SHIFT TRIG SETUP and then uprange or down range if necessary so the unit displays the following CONTINUOUS 2 Press NEXT twice to advance to the interval display message trigger other devices 2 9 1 External Trigger The external trigger input requires a falling edge pulse at TTL logic levels as shown in Figure 2 8 Connections to the rear panel EXTERNAL TRIGGER INPUT jack should be made with a standard BNC connector If the instrument is in the external trigger mode it will be triggered to take readings while in either a continuous or one shot mode when the negative going edge of the external trigger pulse occurs 3 Use uprange or downrange to choose select interval SELECT ON if necessary then press NEXT 4 Press 0 0 35 0 0 in order to program a 3 5sec interval 5 Press NEXT to return to normal display 6 Connect a time varying signal to the instrument and select a fun
166. er removal A Remove the two bottom screws that secure the case cover to the case sides NOTE It is not necessary to remove the feet B Remove the screws that secure the rear bezel then remove the bezel C Carefully slide the cover off the unit to the rear Scariner board removal with option 1992 Pull out the quick disconnect plugs from the rear B Remove the three screws that secure the scanner board to the analog board and rear panel C Grasp the board by the edges and gently pull it _ toward the front of the unit until it clears the rear and side of the case D Partially pull the board free of the unit to allow ac cess to the ribbon cable plug underneath E Unplug the scanner board ribbon cable P1 and remove the scanner board completely from the unit Digital board removal A Disconnect the trigger signal connector P and display board ribbon cable P14 from the board B Remove the screw that secures the digital board to the analog board standoff C Remove the two nuts that secure the IEEE 488 con nector to the rear panel D Remove the four screws that secure the left grooved side panel then remove the side panel 6 14 E Pry the digital board free at connector P16 at the end next to the power transformer until it comes free of the connector pins then remove the board from the unit WARNING _ When removing or installing the digital board be careful of the sharp
167. erminals with the INPUT switch 3 Check and or change the dB reference as previously explained 4 Connect the signal to be measured to the input of the Model 199 5 Enable the dB measurement mode by pressing SHIFT dB 6 Take the dB reading from the display WARNING With dB enabled a hazardous voltage baseline level 40V or more not displayed may pre sent on the input terminals if not sure what is applied to the input assume that a hazardous voltage is present dBm Measurements dBm is defined as decibels above or below a 1mW reference dB measurements can be made in terms of impedance rather than voltage or current Because the instrument cannot directly establish im pedance references a voltage reference must be calculated and established for a particular impedance reference Use the following equation to calculate the voltage reference needed for a particular impedance reference For 0dBm V1mW 2 Example Calculate the voltage reference needed to make dBm measurements referenced to 6002 For 0dBm 0 001W 6000 x6 77456V Once the necessary voltage reference is known it can be established in the Model 199 with the dB program Subse quent dBm readings will be referenced to the correspond ing impedance reference Table 2 4 lists the voltage references needed for some commonly used impedance references dBW Measurements dBW is defined as decibels above or below a IW r
168. ero are affected by changes in input level particularly on ohms and the 300V range Whenever the applied input signal changes press the selected function button to perform an auto routine otherwise substantial measure ment errors will result Zero and calibration may also drift with time thus it is recommended that the selected function button be pressed periodical ly to attain optimum accuracy while auto cal zero is disabled multiplexer off An auto zero cal is performed whenever the range or function is changed Run this program as follows 1 Press DMM SETUP and then NEXT as required until the following message is displayed MUX ON 2 Use uprange or downrange to select multiplexer on off as required For multiplexer off the instrument will display MUX OFF 3 Once the desired multiplexer status is displayed press NEXT to scroll to the next program and save current multiplexer status 2 7 3 IEEE 488 Primary Address Programming The IEEE 488 primary address program allows you check or modify the IEEE 488 primary address of the instrument The factory default primary address is 26 but it can be pro grammed to any valid value between 0 and 30 as outlined below Section 3 contains detailed information on IEEE 488 programming Perform the following steps to use this program 1 Press SHIFT DMM SETUP and then NEXT repeatedly until the following message is displayed 26 IEEE Here we have assumed
169. f the ohms sense leads are not connected the measurement is done 2 termina If the sense leads are connected the measurement is done 4 terminal For 4 terminal measurements rated accuracy can be obtained as long as the maximum lead resistance does not exceed the values listed in Table 2 3 For best results on the 3000 3kQ and 30kQ ranges it is recommended that 4 terminal measurements be made to eliminate errors caused by the voltage drop across the test leads which will occur when 2 terminal measurements are made The Model 5806 Kelvin Test Lead Set is ideal for low resistance 4 terminal measurements In the 4 digit mode use 4 terminal or connect the source leads to the sense leads at the instru ment to avoid extra noise pickup make resistance measurements proceed as follows 1 Select the ohms function by pressing the OHMS button 2 Select a range consistent with the expected resistance or use autorange 3 Select the front or rear panel input terminals using the INPUT switch 4 For 2 terminal measurements connect the resistance to the instrument as shown in Figure 2 4 For 4 terminal measurements connect the resistance to the instrument as shown in Figure 2 5 5 Take the reading from the display Shielded Optional shield Cable jov ome Resistance Under Test MODEL 199 Figure 2 4 Two Terminal Resistance Measurements 30 165A 100 BASIC DMM OPERATION Opti
170. fault Conditions Mode Command Status Enabled AID converter DC volts Send prefix with reading Self Test Clear Enable EOI and bus hold off on X Disabled Internal enabled T75msec SELECT OFF Continuous 300V 544d line cycle integration Continuous on ex ternal trigger No delay CR LF Disabled Multiplex Reading Function Data Format SRQ Filter Interval Data Store Size Range Rate Trigger Delay Terminator Zero _ These defaults can be changed See paragraph 3 9 11 3 11 IEEE 488 PROGRAMMING send the DCL command the controller must perform the following steps 1 Set ATN true 2 Place the DCL command byte on the data bus Notes 1 DCL will return the instrument to the default line fre quency setting 2 DCL will not have any effect on the current IEEE address Programming Example Place the unit in an operating mode that is not a default condition Now enter the follow ing statement into the keyboard CLEAR T Note that the instrument returns to the default conditions 3 8 6 SDC Selective Device Clear The SDC command is an addressed command that per forms essentially the same function as the DCL command However since each device must be individually address ed the SDC command provides a method to clear only a single selected instrument instead of clearing all in struments simultaneously as is the case with When
171. ffected by selected resolution delay multiplexer on off filter on off function and range 2 11 6 Scan Limit For the STEP and SCAN modes the channel limit must be programmed as the last step in the scanner setup pro cess Note that the pole configuration affects the maximum number of channels that can be scanned and thus the channel limit For the 2 pole configuration the maximum limit is eight while the 4 pole mode is limited to four for both modes the minimum limit is one If you attempt to program an improper channel limit the unit will briefly display the following CHAN 4 MAX 8 More information on channel limit programming found in paragraphs 2 118 and 2 11 9 aa 2 11 7 Manual Channel Mode In the MANUAL channel mode individual channels can be accessed by pressing the SCANNER key followed by the number of the channel to close The basic procedure is outlined below 1 Select the function and range required for the measure ment RU 2 Using TRIG SETUP program the trigger mode and delay as required 3 Press SHIFT SCAN SETUP and program 2 pole or 4 pole operation as necessary 4 Press NEXT and note the displayed scan mode If necessary use uprange or downrange to select the following MANUAL 5 Press NEXT and disable or enable the ratio mode as required 6 Press NEXT t complete scanner setup programming 7 To close a specific channel press
172. formation Data Store Indicators STO shows when the instrument is storing data in the data store buffer RCL indicates that data store information is being displayed RCL flashes when data store is full Display Update Indication The decimal point flashes to indicate the display update rate BASIC OMM OPERATION 2 3 2 Power Switch POWER controls AC line power to the instrument Depressing and releasing the switch once turns the power on depressing and releasing the switch a second time turns the power off The on and off positions are marked on the front panel immediately above the POWER switch 2 3 3 Controls The main controls discussed below are all momentary contact switches These controls are numbered on Figure 2 1 Many of the controls have a secondary function that is selected by pressing SHIFT before pressing the control in question SHIFTed controls are placed in parentheses in the following discussions VOLTS STORE VOLTS places the instrument in the volts function See paragraphs 2 64 and 2 6 7 for DCV and measurement information STORE allows access to the data store buffer to select buffer size and initate the storage of readings A third function of this key is to enter the number 0 for some numeric input operations OHMS RECALL OHMS selects the resistance measurement funct on as discussed in paragraph 2 6 6 RECALL allows you to display data store buffer informat
173. ge will be displayed 26 IEEE 2 modify the address key in a new value 0 30 with the numeric data buttons 3 To return to normal operation without permanently changing the address press NEXT six times in succession 4 store the address as the power up address first press NEXT twice then use uprange to display SAVE YES Press NEXT three times to return to normal operation 3 6 CONTROLLER PROGRAMMING A number of IEEE 488 controllers are available each of which has its own programming language In this section we will discuss the programming language for the Hewlett Packard Series 200 and 300 BASIC 4 0 3 6 488 PROGRAMMING 3 6 1 Controller Handler Software Before a specific controller can be used over the IEEE 488 bus it must have IEEE 488 handler software installed With some controllers the software is located in an optional I O ROM and no software installation is necessary on the part of the user In other cases software must be loaded from a diskette and initialized Other small computers that can be used as 488 con trollers may not support all IEEE 488 functions With some interface programming may depend on the particular in terface being used Many times little tricks are necessary to obtain the desired results From the preceding discussion the message is clear make sure the proper software is being used with the interface Often the user may incor
174. ger source to the rear panel BNC EXTERNAL TRIGGER INPUT connector The shield outer part of the connector is connected to digital common Since an internal pull up resistor is us ed a mechanical switch may be connected across the jack contacts Note however that debouncing circuitry will probably be required to avoid a trigger overrun WARNING Do not exceed 30V between digital common and chassis ground to avoid a shock hazard and possible instrument damage 2 Place the instrument in one shot on external trigger or continuous on external trigger mode as explained in paragraph 2 8 1 3 To trigger the instrument apply a pulse to the external trigger input The instrument will process a single reading each time the pulse is applied one shot or start a continuous series of readings 2 21 BASIC DMM OPERATION NOTE Triggering the unit while it is processing a reading from a previous trigger will cause a TRIGGER OVERRUN 2 9 2 Meter Complete The Model 199 has an available output pulse that can be used to trigger other instrumentation A single TTL compatible negative going pulse see Figure 2 9 will ap pear at the METER COMPLETE OUTPUT jack each time the instrument completes a reading To use the voltmeter complete output proceed as follows 1 Connect the Model 199 to the instrument to be triggered with a suitable shielded cable Use a standard BNC con nector to make the connection to th
175. gger One shot or continuous from front panel IEEE 488 bus and rear panel BNC Programmable Reading Interval 15ms to 999 9995 Programmable Trigger Delay ims to 999 9995 WITH MODEL 1992 8 CHANNEL SCANNER Programmable Configuration 2 or 4 pole Programmable Channel Limit 1 to 8 Programmable Scanning Modes Manual step and scan Ratio Channels 2 through 8 referenced to Channel 1 GENERAL MAXIMUM READING 302 999 counts in 5 digit mode CONNECTORS Measurement Switch selectable front or rear safety jacks Digital TRIGGER input and METER COMPLETE output on rear panel BNCs WARMUP 2 hours to rated accuracy TEMPERATURE COEFFICIENT 0 18 C amp 28 50 C lt 0 1 x applicable accuracy specification C ISOLATION Input LO to IEEE LO or power line ground 500V peak 5 x 10 VeHz maximum gt 1090 paralleled by 400pF OPERATING ENVIRONMENT 0 50 80 relative humidity up to 35 C linearly derate 3 RH C 35 50 C 0 60 RH up to 28 C on range STORAGE ENVIRONMENT 259 to 65 POWER 105 125V or 210 250V rear panel switch selected 50Hz or 60Hz 20VA maximum 90 110V and 180 220V ver sions available upon request DIMENSIONS WEIGHT 90mm high x 220mm wide x 330mm deep 3 in x 8 in x 12 in Net 3kg 6 lbs 8 oz ACCESSORIES SUPPLIED Mode 1751 Safety Test Leads Instruction Manual ACCESSORIES AVAILABLE Model 1
176. gnored Before 2 Set false programming over the bus press NEXT as many times 4 Send the command string over the bus one byte at a as necessary to exit the menu time Table 3 8 Device Dependent Command Summary 1 other device dependent commands Fanchon DC volts 3 9 2 volts Ohms DC curr nt AC current ACV dB ACA dB ACV DCA Ohms ACV dB ACA dB Auto Auto Auto Auto 300mV 300mV 30mA 30mA 300 Q Auto Auto Auto 30V 30V 30k2 Auto Auto 300 300 V 300kQ0 Auto Auto 300 V30 V Auto Auto 00 V300 V 30MQ 00 V300 V 3 300MQ R6 R7 3 Zero 20 Zero disabled 3 94 21 Zero enabled 22 Zero enabled using a zero value Filter Internal and front panel filter disabled 3 9 5 Internal filter enabled n Front panel filter enabled 3 9 6 digit resolution 2 59msec integration period 5 digit resolution line cycle integration 16 67msec 20msec 50Hz Trigger Continuous on Talk One shot on Talk Continuous on GET One shot on GET Continuous on X One shot on X Continuous on External Trigger One shot on External Trigger Reading Mode Readings from A D converter 3 98 individual readings from data store B2 All readings from data store buffer dump Data Store Size Wrap around data store mode 3 9 9 Data store of n n 1 to 500 3 14
177. gs V2XZ2X will result with zero being enabled and the instrument reading 1 5 0 5 2 0 1 5 f no V is value is programmed a value of 0 is assumed NOTE In a one shot trigger mode you must trigger the unit after sending the Z command to complete zero programming ZERO will flash after sending 71 until the unit is triggered Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition Programming Example Set the instrument to the DC range With the front panel ZERO button disable the zero mode if enabled and enter the following statements into the HP 85 keyboard REMOTE 725 OUTPUT Peet UL OUTPUT 72 amp z1x After the third statement the ZERO indicator will turn with a zero baseline of IVDC 3 9 5 Filter P The filter command controls the amount of filtering ap plied to the input signal The Model 199 filters the signal by taking the average of a number of successive reading samples Since noise is mostly random in nature it can be largely cancelled out with this method Paragraph 2 6 3 discusses filtering in more detail PO No filtering P1 Internal filter enabled Front panel filter enabled Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition Programming Example With the front panel FILTER in dicator off enter the following statements into the computer
178. he E If the reading is not 10 0000V 1800 counts then high 300V range capacitor C49 see Figure 67 for a display frequency will have to be adjusted as explained in the reading of 100 000V 500 counts following procedure step 6 If the high frequency readings were within the defined range step 6 does not have to be performed and ACV calibration is NOTE completed If the optional Model 1992 Scanner is installed the adjustments are accessible through holes in the 6 High Frequency Adjustment Scanner board A Remove the top cover to gain access to the adjustments B With the AC VOLTS function and 52d resolution E Set the Model 199 to the 30V range and set the AC selected connect the AC calibrator to the instrument calibrator to output 10 0000V at 70kHz as shown in Figure 6 6 K After allowing the measurement to settle adjust the C Set the Model 199 to the 300V range and set the AC 30V range capacitor C48 for a display reading of calibrator to output 100 000V at a frequency of 70kHz 10 0000V 500 counts G Repeat steps C through F until no other adjustments need to be made WARNING H Put the top cover back on Some procedures require the use of high voltage Take care to prevent contact with live circuits which could cause electrical shock resulting in injury or death The shield on the analog board is at input low potential and may have up to 500V on it Use an insulated align ment tool to make the follo
179. he calibrator to the SHORT position and enable zero on the Model 199 Verify that the display reads 000 000 Set the calibrator to output 1900 and verify that the reading is within the limits listed in Table 4 4 Disable zero and leave it disabled for the remainder of the ohms verification procedure Utilizing Figures 4 3 and 4 4 check the through 300M2 ranges by applying the respective resistance levels listed in Table 4 4 Verify that the readings are within the limits listed in the table 4 3 PERFORMANCE VERIFICATION Table 4 4 Limits for Ohms Verification Applied Allowable Readings 199 Range D Resistance 18 C to 28 C Figure 4 3 Figure 4 3 Figure 4 3 Figure 4 4 Figure 4 4 Figure 4 4 Figure 4 4 Output Resistance Sense Calibrator Lsense to 54508 MODEL 199 Output LO Figure 4 3 Connections for Ohms Verification 3000 30 0 Range Output Resistance Calibrator Model 54504 Figure 4 4 Connections for Ohms Verification 300 0 300 2 Ranges 190 000 Q 1 90000 19 0000 190 000 1 90000MQ 19 0000MQ 100 000 30mA 30 0000mA 3 00000 A 189 973 190 027 1 89980 to 1 90020 18 9980 to 19 0020 189 948 190 052 1 89940 1 90060 18 9767 to 19 0233 97 995 to 102 005 4 5 4 DC Current Verification With the instrument set to 5124 resolution verify the DC current function as fol
180. he instrument will display dashes after changing resolution until a new reading is available for display The integration period of the A D converter is 2 59msec in the 414 digit mode while line cycle integration 20msec 50Hz 16 67msec 60HZ is used for 5 5 digits Thus the selected resolution affects the overall reading rate as does the selected function and amount of filtering BASIC DMM OPERATION 2 6 4 DC Voltage Measurements The Model 199 can be used to make DC voltage measure ments the range of 1nV to 300V _Use the following procedures to make DC voltage measurements CAUTION The maximum input voltage between the HI and LO terminals is 425V peak or 300V RMS whichever is less Exceeding this value may cause instrument damage 1 Select the DC volts function by pressing the VOLTS button 2 Select a range consistent with the expected voltage or use autorange 3 Select the front or rear panel input terminals with the INPUT switch NOTE The 300mV DC range requires zero to be set in order to achieve rated accuracy The zero corr c tion procedure can be found in paragraph 2 6 2 4 Connect the signal to be measured to the selected in put terminals as shown in Figure 2 3 5 Take the reading from the display DC Voltage Source MODEL 199 Caution Maximum input 300V RMS 425V Peak Input Resistance 300mV gt 120 30 11 300V 10 Figure 2 3 DC Voltage Mea
181. igure 3 10 OUT A and OUT B are strapped together to H L to L and then connected to the VOLTS OHMS terminals of the Model 199 the rear panel ter minals are most convenient for scanner use just be sure the rear panel terminals are selected with the front panel switch In the case of the 4 pole connections OUT A is connected to the VOLTS OHMS terminals while OUT is connected to the OHMS SENSE terminals Example Program The program below can be used to test resistors as outlined above The program will prompt you as to whether the 2 pole or 4 pole mode is to be used and then program the instrument accordingly In order to use the program per form the following steps 1 Connect the resistors to the scanner as shown in Figure 3 10 or 3 11 For resistances below the 4 pole mode is recommended for rated accuracy 2 Enter the lines below into the computer and check the program for errors 3 Run the program and select the 2 or 4 pole mode as required 4 The test will then be run and the results will be shown on the computer CRT The results will be shown as a percent of tolerance from the reference resistor con nected to channel 1 and 5 for the 4 mode IEEE 488 PROGRAMMING Annee ent AA TAA EEA CH 8 CH 7 6 CHS Resistors Under Test CH 4 CH 3 i CH2 iC CH 1 i Reference Resistor d 1992 CARD To 199 Volts
182. ilter uses a fixed window of 1000 counts with 30 readings averaged per reading on all ranges and functions NOTES 1 In a continuous trigger mode the FLTR indicator will flash until the filter is settled Readings will continue to update the display while the filter is settling but the display will not represent the final filtered reading value until FLTR stops flashing when the proper number of readings have been averaged 2 In a one shot trigger mode no readings will be displayed or transmitted over the IEEE 488 bus until the filter has settled Each trigger clears the filter fills the filter with new readings and then issues a METER com plete pulse once the reading is available Therefore filtered one shot times can be long 3 The filter can be turned off entirely by sending the POX command over the IEEE 488 bus see paragraph 3 9 Resolution The Model 199 can be operated with either 47 or 5 digits of display resolution In the 412 digit mode the instrument displays 230 300 counts while 303 000 counts are displayed in the 5 2 digit mode The resolution can be pro grammed separately for each of the five measuring functions NOTE On the 300kQ and higher resistance ranges only 535 digit resolution is available To change display resolution press SHIFT RESOLN The display will toggle to the opposite resolution each time you perform this keystroke sequence Note that changing the resolution restarts the filter t
183. ine fuse protects the line power input of the instrument and the current fuse protects the current function from excessive current The fuses may be replac ed by using the procedures found in the following paragraphs WARNING Disconnect the instrument from the power line and from other equipment before replacing fuses 6 3 1 Line Fuse To replace the line fuse proceed as follows 1 Turn off the power and disconnect the line cord and all other test cables from the instrument 2 Place the end of a flat blade screwdriver into the slot in the line fuse holder on the rear panel Push in and rotate the fuse carrier one quarter turn counterclockwise Release pressure on the holder and its internal spring will push the fuse and the carrier out of the holder 3 Remove the fuse and replace it with the proper type using Table 6 2 as a guide 6 1 MAINTENANCE CAUTION Do not use a fuse with a rating higher than specified or instrument damage may occur If the instrument repeatedly blows fuses locate and correct the cause of the trouble before replacing the fuse 4 nstall the new fuse and the carrier into the holder by reversing the above procedure Table 6 2 Line Fuse Replacement line E Keithley Voltage Fuse Type Part No 105 125 3 16 250V Slo Blo FU 29 210V 250V 1 10 250V Slo Blo FU 40 6 3 2 Current Fuse The current fuse protects the 30mA and
184. ion Zero state on off Filter state on off AC dB state on off Multiplexer on off Trigger delay Reading interval IEEE 488 primary address Line frequency 50 or 60Hz In order to save an instrument setup proceed as follows 1 Setup instrument operating conditions as desired or use the reset program paragraph 2 7 8 to save default operating conditions 2 Press SHIFT DMM SETUP and then NEXT until the following message appears SAVE NO 3 Use uprange or downrange to toggle to the following message SAVE YES 4 To save instrument setup conditions press NEXT The unit will save the operating states and then go on to the next program NOTES 1 70 exit the program without changing the previous default conditions press NEXT with the SAVE NO message displayed 2 To return the instrument to the factory power up default conditions use the reset program and then save those conditions using the save setup program BASIC DMM OPERATION 2 7 6 LED Test This program allows you to test all the front panel annun ciators and LED display segments to check for operation Proceed as follows 1 Press DMM SETUP and then NEXT repeatedly until the following message is displayed LEDS OFF 2 To test the LEDs use uprange or downrange to toggle the display to the following LEDS ON 3 Press NEXT to initiate the test v ES 4 During the test the instrument will turn
185. ion of dissimilar metals These can be large compared to the signal which the Model 199 can measure Thermal emfs can cause the following problems 1 Instability or zero offset is much higher than expected 2 The reading is sensitive to and responds to temperature changes This effect can be demonstrated by touching the circuit by placing a heat source near the circuit or by a regular pattern of instability cor responding to heating and air conditioning systems or changes in sunlight 3 To minimize the drift caused by thermal emfs use cop per leads to connect the circuit to the Model 199 A banana plug is generally suitable and generates just a few microvolts A clean copper conductor such as 10 bus wire is about the best for this application The leads _to the input may be shielded or unshielded as necessary Refer to Shielding 4 Widely varying temperatures within the circuit can also create thermal emfs Therefore maintain constant temperatures to minimize these thermal emfs A card board box around the circuit under test also helps by minimizing air currents 5 The ZERO control can be used to null out constant off set voltages 6 Additional thermals may be generated by the optional Model 1992 Scanner 2 6 6 Resistance Measurements The Model 199 can make resistance measurements from 110 to 300M2 The Model 199 provides automatic selec tion of 2 terminal or 4 terminal resistance measurements This means that i
186. ion on the front panel display A third function of this key is to enter the number 1 for numeric input operations AMPS FILTER The AMPS buttons select current measurement as discussed in paragraph 2 68 FILTER toggles the filter between internal and user filter FLTR on for user See paragraph 2 6 3 for details on filter operation The third function of this key is to enter the number 2 when numeric input is required AC dB AC selects AC volts or AC current measurement depending on whether VOLTS or AMPS is in effect dB toggles the dB function on _ or off for AC voltage or current measurements 0dB reference for these functions is volts or imA amps Paragraph 2 6 9 gives more information on dB measurements The third function of this key is to enter the number 3 for numeric inputs ZERO RESOLN ZERO enables the zero mode which allows baseline values to be subtracted from subsequent measurements and can also be used for zero correction paragraph 2 6 2 RESOLN toggles the display between 4 digit and 5 digit resolution The third function for this key is to enter the number 4 when numeric input is required LOCAL The LOCAL key takes the instrument out of remote when it is being used over the IEEE 488 bus Note that all other control keys will be locked out when the unit is in remote LOCAL will also be inoperative when LLO is in effect AUTO DMM SETUP AUTO places the
187. itry If the test fails the instrument will lock up with the following message displayed _ 0000000000 Replacing U4 may correct the problem 2 If the ROM test passes a digital self test will then be performed on the RAM circuitry If the RAM test fails the instrument will lock up with the following error message displayed AAAAAAAAAA Replacing U9 may solve the problem 3 Finally the circuitry where the calibration con stants IEEE address and line frequency settings are stored will be checked If this test fails the following message displayed UNCAL Pressing any front panel momentary button will return the instrument to normal operation however a complete calibration will have to be performed and the IEEE ad dress and line frequency setting should be checked If the test still fails after calibration try replacing U20 before recalibrating the instrument again 4 The instrument will then go to the power up default function MAINTENANCE Table 6 10 Recommended Troubieshooting Equipment Five function DMM with 0 1 basic DCV accuracy 10M input impedance Dual trace triggered sweep oscilloscope DC to 50MHz Digital frequency counter 6 7 3 Diagnostics Two programs available under DMM SETUP allow you to test the front panel LEDs as well as perform the memory tests that are automatically performed upon power up Also included is a troubleshooting test mode that is design ed to turn o
188. l 5 IU 4 ier 9e meth 44 lt 4 4 4 Byte Format E XO mo eqs ee 41 444 gt 4 4 COP EC TT 4 4 mm m m mms te o ttt Amr wire tit titt tmt s est tmo 1 4 4 n en 1211136 re ee ee tM ee ee ee a ee oppene Mtr tr t n sw ee rtt rA AA 4 4 4 f m tttm
189. l be displayed 0 00000 VDC rm 30 If a calibration point other than the one displayed is to be used then change the display to the desired value as explained in step 4 Set the level of the calibration signal to agree with the displayed calibration point 12 Press the NEXT button The following message will be displayed for several seconds WORKING 13 The calibration points will be stored in E7PROM and the instrument will now exit the calibration program Select the next range and function to be calibrated and repeat steps 3 through 12 NOTE If the calibration source has an offset set the calibration points to agree with the actual output of the source For example if the source has DC offset on the 300mV DC range set the calibration points for 300 001mV and 000 001mV 6 4 6 IEEE 488 Bus Calibration 488 bus calibration is performed in a manner similar to front panel calibration except that calibration constants Connect the calibration signal to the instrument 6 Press the NEXT button The following will be are transmitted over the bus instead of being entered from the front panel By combining appropriate JEEE 488 com patible calibration equipment with a suitable test program calibration of the Model 199 could be performed on an automated basis Refer to Section 3 for complete informa tion on using the 488 bus The following informa tion provides the basic procedure fo
190. l display then use uprange or downrange to select interval For select interval use the data entry keys to program the desired interval in the range of 25msec to 999 999sec Keep in mind that the interval is the time period between channel sets not individual channels as is the case with the STEP mode 5 Press NEXT to return to normal display once the 6 7 desired interval has been programmed Press SHIFT SCAN SETUP and program the pole and mode as desired Advance to the scan mode display by pressing N EXT then select the scan mode with the following display SCAN Press NEXT to program the ratio and return to normal display Press SCANNER and program the channel limit at the following prompt LIMIT 10 11 12 Key in the desired limit 1 8 2 pole 1 4 4 with the data entry keys The unit will then begin scanning one set of channels per programmed interval displaying the channels numbers as they are sequenced stop scanning and return to normal display program a channel limit of 0 To do so press SCANNER 0 NOTES 1 Triggered Scanning or Because of the relatively rapid scanning rate it may be difficult to read data from the display while the unit is scanning For that reason it is recommended that the SCAN mode be used with data store as discussed in paragraph 2 1 11 The INTERVAL OVERRUN message will be displayed if the unit cannot scan channel sets at
191. locked out when calibrating CONFLICT Unit in invalid state when calibrating autorange NO DATA Entering recall with no data stored NO SCANNER Scanner not installed TYPICAL 5 DIGIT CONVERSION TIMES ACA 110msec 133msec MUX OFF 28msec 33msec MUX ON OHMS range and lower 110 133msec OFF 63msec 78msec Times in parenthesis are for 50Hz operation TYPICAL AUTORANGING TIMES DCV DCA 350msec ACV ACA 14sec OHMS 300kQ range and lower 500msec Times shown are to correct range and do not include conversion times for final reading Scanner Operation SCAN SETUP SHIFI SCAN SETUP to enter menu NEXT to scroll to next menu option 2POLE POLE L 4POLE MANUAL Allows channel to be manually closed with SCANNER Key Mode STEP Increments one channel per interval or trigger SCAN Scans one set of channels per interval or trig ger minimum time between channels ON Channels 2 through 8 referenced to channel 1 RATIO AIV L OFF Ratio operates only on a fixed range Range changes will restart at channel 1 e In MANUAL at least one reading must be taken on channel 1 before at tempting to display ratio on channels 2 8 ACTIVATING THE SCANNER SCANNER followed by number 1 8 activates the scanner In MANUAL channel number selects channel to be closed In STEP or SCAN number selects channel li
192. low signals to settle before each measurement The scan delay settling time can be programmed be sen ding the W command as follows Wn 3 39 488 PROGRAMMING Here n represents the delay period in mesec with allowable range of Omsec to 999 999msec The factory default value for the delay parameter is Omsec The instru ment will assume that value upon power up of after DCL or SDC NOTES 1 An INTERVAL OVERRUN error will occur if the pro grammed interval is too short for the present instrument configuration 2 The programmed interval also affects the reading rate as well as the data store interval in 1 the continuous trig ger mode 3 A trigger delay of at least one second should be used with AC measurements 4 The programmed interval must be longer than the delay time or an INTERVAL OVERRUN error will occur 3 12 4 Using Data Store with the Scanner Scanner data can easily be stored within the data store buf fer for later recall The following discussion provides a general outline of programming methods for doing so Some modification of these methods may be necessary for your particular application Scanner Programming Basically program the unit as follows 1 Program the scanner for 2 or 4 pole operation with the command For example for 2 pole mode send Be sure that connections are proper for the selected mode see paragraph 2 11 for det
193. lows CAUTION Do not exceed 3A to the AMPS and LO input ter minals or the front panel current fuse will blow 1 Select the DCA function and autorange 2 Connect the DC current calibration source to the Model 199 as shown in Figure 4 5 3 Set the calibration source to output 30mA and verify that the reading is within the limits listed in Table 4 5 4 Repeat the procedure for the range by applying the DC current level listed in Table 4 5 Check to see that the reading is within the limits listed in the table 5 Repeat the procedure for each of the two ranges with negative current levels Table 4 5 Limits for DC Current Verification Applied 199 Range DC Current Allowable Readings 18 C to 28 C 29 9835 to 30 0165 2 99685 to 3 00315 4 4 PERFORMANCE VERIFICATION Shielded DC Voltage Calibrator Current Calibrator Model 25002 Model 5440A H Shielded Cable Figure 4 5 Connections for DC Current Verification 4 5 5 TRMS AC Current Verification With the instrument set for 5724 resolution YE the AC current function as follows CAUTION Do not exceed 3A to the AMPS and LO input ter minals or the front panel current fuse will blow 1 Select the ACA function and autorange Do not use zero to cancel any offset in this procedure 2 Connect the AC current calibration source to the Model 199 as shown in Figure 4 6 3 Set the calibration source to output 30mA
194. lows K 0 707 0 637 1 11 By applying this correction factor to averaged reading a typical meter can be designed to give the RMS equivalent This works fine as long as the waveform is a pure sine but the ratios between the RMS and average values of different waveforms is far from constant and can vary considerably Table 2 5 shows a comparison of comunon types of wave forms For reference the first waveform is an ordinary sine wave with a peak amplitude of 10V The average value of the voltage is 6 37V while its RMS value is 707V If we app ly the 1 11 correction factor to the average reading it can be seen that both meters will give the same reading resulting is no error in the average type meter reading The situation changes with the half wave rectified sine wave As before the peak value of the waveform is 10 but the average value drops to 3 18V The RMS value of this waveform is 3 86V but the average responding meter will give a reading of 3 53V 3 18 x 1 11 creating an error of 11 similar situation exists for the rectified square wave which has an average value of 5V and an RMS value of 5 0V The average responding meter gives a TRMS reading of 5 55V 5 x 1 11 while the Model 199 gives TRMS reading of 5V Other waveform comparisons can be found in Table 2 5 AC Voltage Offset The Model 199 at 542d resolution will typically display 150 counts of offset on AC volts with the in
195. lt conditions DATA FORMAT GO Reading with prefix G1 Reading without prefix G2 Reading and buffer location with prefix G3 Reading and buffer location without prefix 64 Reading and channel with prefix G5 Reading and channel without prefix G6 Reading buffer location and channel with prefix G7 Reading buffer location and channel without prefix SRQ 0 Disable Mi Reading overflow M2 Data store full M4 Data store half full 8 Reading done M16 Ready M32 Error EOI AND BUS HOLD OFF Enable EOI and bus hold off on X Disable enable bus hold off on X K2 Enable EOI disable bus hold off on X K3 Disable both EO and bus hold off on X TERMINATOR YO CR LF Y1 LF CR Y2 CR Y3 LF STATUS 00 Send machine status word 01 Send error conditions U2 Send Translator word list u3 Send buffer size U4 Send current value of V US Send input switch status front rear MULTIPLEX AO Auto Cal multiplex disabled A1 Auto Cal multiplex enabled DELAY Wn n delay period in milliseconds Qmsec to 999999msec SELF TEST 10 Test ROM RAM HIT BUTTON Hn Hit front panel button number n DISPLAY Da Display up to 10 character message a character D Cancel display mode SCANNER PROGRAMMING COMMANDS SCANNER SETUP MANUAL NO All channels open 2 pole 4 pole 1 1 1 N2 2 2 N3 3 3 N4 4 4 N5 5 CHAN 4 MAX ERROR 6 6 CHAN 4 ERROR 7 7 CHAN 4 MAX ERROR N8 8 CHAN 4 MAX ERROR N9 CHAN 8 MAX ERROR CHAN
196. ltage Reference Levels for Impedance References E ers 2 5 Comparison of Average and TRMS Meter Readings 5 2 6 DMM Setup 27 Typical Minimum Usable Scan Intervals 2 SECTION 3 IEEE 488 Progamming 3 1 TEEE 488 Commands USed to Select Function and 3 2 IEEE Contact 2722 ive oes ae mc 3 3 Model 199 Interface Function nca vum 3 4 BASIC Statements Necessary to Send Bus Cbmmsuda 3 5 Front Panel IEEE 488 r 3 6 General Bus Commands and Associated BASIC Statements m 37 Factory Default Conditions T mn 3 8 Device Dependent Command Summary 3 9 Range Command ree n 310 Rate Command Summary aie aden te ee M ees 3 1 Command Parameters UID EI 312 Bus Hold off Times n 313 Translator Reserved Words and
197. m ratio is 9 99999 Exceeding this value will cause an overflow error 2 11 5 Reading Interval The reading interval parameter determines the time period between channels for the STEP mode or the time between channel sets in the SCAN mode when the unit is in the continuous trigger mode In one shot the trigger period BASIC DMM OPERATION determines the interval Use the procedure below to pro gram the scan interval 1 Press SHIFT TRIG SETUP and then NEXT as necessary so that the SELECT message is displayed then use uprange or downrange to select the desired interval mode and press NEXT Keep in mind that a 175msec in terval is automatically selected in the SELECT OFF 2 For the select interval key in the desired scan interval in the range of 25msec to 999 99sec 3 Press NEXT to complete interval programming once the desired interval is keyed in NOTES 1 The programmed interval also affects the display update rate as well as the data store interval while in the con tinuous trigger mode 2 Programming an interval that is too short for the pre sent instrument configuration will result in the INTER VAL OVERRUN error Under these conditions the in strument will continue to scan as fast as it can but it will not scan at the programmed interval Although the minimum programmable interval is 15 the minimum usable interval with the scanner is 25msec ub 4 Scanning rate is a
198. marized in Table 3 9 The instrument will be ready to take a reading after the range is set up when responding to a range command Upon power up or after the instrument receives a DCL or SDC command the Model 199 will return to the default condition Programming Example Make sure the instrument is in the autorange mode and then enter the following statements into the computer 5 Paes TRS 3 16 IEEE 488 PROGRAMMING Table 3 9 Range Command Summary Command Pev ACA Ohms ACV as ACA a The instrument cancels the autorange mode and enters the R3 range instead 3 9 4 Zero 2 Over the bus the zero modifier can be controlled in the same way that it is controlled from the front panel Refer to paragraph 2 6 2 for a complete description of the zero modifier The zero modifier is controlled by sending one of the following zero commands over the bus ZO Zero disabled 71 Zero enabled Z2 Zero enabled using a zero value V Sending 21 has the same effect as pressing the ZERO but ton Zero will enable and the display will zero with the input signal becoming the zero baseline level The Z2 command is used when a zero value using the V command has already been established When the Z2 command is sent subsequent readings represent the dif ference between the input signal and the value of V For example with 0 5V on the input sending the command strin
199. microprocessor using this equation Reer VO SENSE HI SENSE LO Ry REF HI REF LO For the 3002 range SENSE HI and VQ SENSE LO are actually multipled by a factor of 10 in the input buffer circuit Protection on the ohms ranges is accomplished by and Q16 For an input voltage applied to the Q input terminals Q16 clamps the voltage to the reference resistors to a safe limit RT1 limits the current to Q9 and 16 The Model 199 is equipped to make 2 or 4 terminal resis tance measurements Generally 4 terminal measurements should be made on the 3000 range because the relatively large output current can develop a significant voltage across the test leads affecting measurement accuracy Figure 5 2 shows the equivalent circuit of the input circuit Rx is the unknown measured resistance and Ri R2 and R4 represent the test lead resistance R2 and are connected only during 4 terminal measurements When using a 2 terminal configuration all the current flows through the test leads R1 and R4 If Ry has a low value the amount of voltage developed across the test leads can be significant Since the voltage is sensed across the combined resistance of R Rx and R4 considerable error be introduced in to the reading To use a 4 terminal connection a second set of leads R2 and R3 are connected to the unknown resistance The amount of current through R2 and R3 is much smaller than the
200. mits and starts scanning process STOPPING THE SCANNER Opening all Channels SCANNER followed by 0 DETERMINING SCANNING INTERVAL Scanning without selecting interval Program INTERVAL SELECT to interval is T75msec depending on other selected parameters INTERVAL OVERRUN message will not be displayed Minimum Interval Time Calculation Interval time is the sum of 1 conversions per channel x conversion time 2 Programmed DELAY time per channel 3 Break before make time 17msec 4 Auto range time if used STEP mode calculated time above is the INTERVAL setting In SCAN mode sum of 1 4 x number channels scanned is the minimum interval setting SCANNER OPERATION NOTES When using the scanner with STEP or SCAN switching the DMM will take readings on each channel as if it were in the one shot mode whether programmed to CONTINUOUS or ONE SHOT Conversions are automatically synchronized to channel closures Channels will not close in the middle of conversions Any programmed DELAY is inserted between channel closure and start of conversion with scanner disabled DELAY is inserted bet ween trigger and start of conversion Readings on each channel consist of multiple conversions to fill the Running Average User Filter 30 conversions or Running Average Internal Filter when active 5129 only varies by range and function see manual Scanner switching is break bef
201. mmed over the IEEE 488 bus as described in Section 3 2 2 POWER UP PROCEDURE 2 2 1 Line Power Use the following procedure to connect the Model 199 to line power and power up the instrument 1 Check that the instrument is set to correspond to the available line power When the instrument leaves the factory the externally selected line voltage is marked on the rear panel Ranges are 105V 125V or 210 250 50 60Hz AC 90 110V 180 220V with optional trans former If the line voltage setting of the instrument needs to be changed set switch as required If the line frequency setting of the instrument needs to be checked and or changed utilize front panel DMM SETUP see paragraph 2 7 after the instrument completes the power up sequence the line frequency is displayed upon power up 2 Connect the female end of the power cord to the AC receptacle on the rear panel of the instrument Connect the other end of the cord to a grounded AC outlet WARNING The Model 199 is equipped with a 3 wire power cord that contains a separate ground wire and is designed to be used with grounded outlets When proper connections are made instrument chassis is connected to power line ground Failure to use a grounded outlet may result in personal injury or death because of electric shock CAUTION Be sure that the power line voltage agrees with the indicated range on the rear panel of the in strument Failure to observe this precaution may resul
202. n formation on triggering A third function of this key is to enter the number 9 SHIFT NEXT SHIFT allows access to secondary functions of many of the control keys for example DMM SETUP NEXT scrolls through menu selec tions for those functions with menus BASIC DMM OPERATION 2 3 4 CAL LOCK Switch The CAL LOCK switch disables calibration from the front panel or over the IEEE 488 bus Before the unit can be calibrated this switch must be enabled See paragraph 64 for more calibration information 2 3 5 INPUT 4 The front panel INPUT switch selects between the front and rear panel input terminals Front panel terminals are selected with the switch out while rear panel terminals are selected with the switch in The switch positions are marked immediately above the switch on the front panel 2 3 6 Current Input Fusel 5 The current input fuse is a normal blow fuse that pro tects the AMPS input from excessive current See paragraph 6 3 for fuse replacement procedures in the following paragraphs 2 3 7 Input Terminals The input terminals are intended to be used with safety shrouded test leads to help minimize the possibility of con tact with live circuits Note that all the terminals except AMPS are duplicated on the rear panel The front panel INPUT switch determines which set of terminals is active VOLTS OHMS HI and LO The VOLTS OHMS HI and LO terminals are used f
203. n 3 15V 15 0 75V Referenced to analog common 050 pin 3 Table 6 13 Digital Circuitry Checks m U9 020 Pass SRAM ROM and Display will lock if failure self test on power up occurs U8 pin 2 PA0 TIL level pulses every imsec VIA clock U8 pin 3 PAI TTL level pulses every I5msec Data U8 pin 6 PA4 Switch data 5 or OV Data input to VIA when button ressed U8 pin 7 PA5 Switch data 5V or OV Data input to VIA when bution ressed U8 pin 8 Switch data 5V or OV input to VIA when button pressed U8 pin 9 PA7 Switch data 5V or OV Data input to VIA when button pressed U8 pin 19 Variable pulse train OV to 5V VIA Data Line UH pin 4 Variable pulse train OV to 45V Data output 13 Variable pulse train OV to 5V A D counts U8 pins 12 through 16 Variable pulse train OV to 5V Data to VIA from A D 110 pins 34 and 35 2MHz TTL Bus Clock U10 pin 37 5V 5 Reset line goes low briefly on power up US pin 9 45V signal pulsed OV to 5V INT line every Imsec 05 pin 19 45V Logic 1 RESET line 05 pin 18 2MHz square wave at OV to 5V Clock U5 pin 28 Should go true 0V when line command is sent U5 24 NDAC 25 NRFD Refer to Figure C 2 for required Handshake sequence 26 DAV and the data lines conditions 6 21 MAINTENANCE Table 6 14 Display Circuitry Checks U4 and 15 pins 2 9 and pins 6
204. n the various relays and switching FETs to allow signal tracing through the instrument Perform the follow ing steps in order to test the instrument 1 Select the range and function to be tested for signal tracing en 2 Press SHIFT DMM SETUP then NEXT four times so that the instrument displays the following LEDS OFF 3 Use uprange downrange to select the following display T LEDS ON 4 Press NEXT to initiate the LED test 5 While the LED test is running observe the front panel LEDs and display segments to verify that all are func tioning properly 6 At the conclusion of the LED test the instrument will display the following DEBUG OFF 7 Press uprange or downrange to display the following DEBUG ON 8 Press NEXT to enter the diagnostic test The unit will display that the first N mode is selected as follows N 01 9 Using Table 6 11 reference the selected N mode to the present range and function to determine which switch 6 18 6 7 3 Power supply and DC voltage checks analog signal tracing continuity logic levels Digital and analog waveform checks Checking clock frequencies ing FETs and relays should be on Apply an ap propriate signal to the instrument and trace the signal through the unit using the appropriate schematic as a guide 10 To change the N mode press the TRIGGER button 11 To troubleshoot a different range or function first exit the diagnostic program by p
205. nalog switch U21A is closed on this range amplifier U26A has a feedback resistance of 118kQ R32 in parallel with 13kQ R24 resulting in a gain factor of 1 100 The divided signal is then xouted through analog switch U21B and buf fer U26B to the TRMS converter U27 DCV Input AD moves ume Scanner Inputs Scanner Optional lt lt i 488 interface Analog Digitai Front Buttons Figure 5 1 Overall Block Diagram 5 2 PRINCIPLES OF OPERATION OHMS Resistance measurements are made using the ratiometric technique see Figure 5 2 When the resistance function is selected a series circuit is formed between the ohms source a reference resistor and the external unknown resistance A current flows through the reference resistor and the unknown resistance Since this current is common to both resistances the value of the unknown resistance can be calculated by measuring the voltage across the reference resistor and the voltage across the unknown resistance The following ohms reference resistors are used see Figure 5 3 3000 and ranges R26 2k 30kQ range R23 30kQ 300 0 range RI7B 1 100 0 3M0 range RIA R17B 30M2 and 300 0 ranges RYA 10MQ By measuring the four inputs to the A D converter the unknown resistance can be computed by the
206. nd functions Programming the instrument for shorter times will result _in the INTERVAL OVERRUN message in which case the unit will scan slower than the programmed interval Times for both the STEP and SCAN modes are given at both 4 digit and 5 digit resolution where applicable and all times are with internal filter on FLTR off and MUX ON For DC and ohms functions turning the internal filter off using POX over the bus and mutiplexer off will shorten the times somewhat times will typically be about 10 30 shorter with the multiplexer and filter off Conversely operating the instrument with the front panel filter on FLTR on will increase the minimum interval times Table 2 7 Typical Minimum Usable Scan Intervals Range and STEP Mode SCAN Mode Function 47 Digit 5 Digit 680msec 35msec 590msec 700msec 1 3sec 5 sec 7sec 380msec 150msec 35msec 150msec 360msec 360msec NOTES 1 All times are typical 2 Times shown are with FLTR off MUX ON 3 Scan mode times are with eight channel limit BASIC DMM OPERATION Low Level Voltages Under Test ts s Ate I S A EA S n rot 1992 CARD Use pure copper wire to avoid thermais Connect cable mV Input directly to output 181 Nanovoltmeter Low Thermal Cable 1507 Figure 2 17 Using Scanner Card with Nanovoltmeter 2 39 2 40 SECTION 3 IEEE 488 Programming 3 1 INTRODUCTION This secti
207. nd option Table 3 1 summarizes the commands used to select function and range A number of commands can be grouped together in one string if desired Also you must terminate the command or command string with the X character in order for the instrument to execute the commands in question if you are using the programming example from Step 3 above simply type in the command string when prompted to do so Some example strings are given below F3X select DCA function FOR2X select function 3V range IEEE 488 PROGRAMMING Step 5 Get Readings from the Model 199 Usually you will want to obtain one or more readings from the Model 199 In the example program above a single reading is requested and displayed after each command In other cases you may wish to program the instrument configuration at the beginning of your program and then obtain a whole series of measurements The basic reading string that the Model 199 sends over the bus is in ASCII characters of the form NDCV 1 23456E 0 where N indicates a normal reading O would indicate an overflow DCV shows the function in effect in this case DC volts 1 23456 is the mantissa of the reading data 0 represents the exponent Table 3 1 IEEE 488 Commands Used to Select Function and Range Function FO Fl F2 F3 F5 F6 Mode Command Description Execute other device dependent commands
208. ned When send ing the command word over the bus the device dependent command that was last entered will prevail For example sending a Translator word in place of FOFIX will place the instrument in the F1 function NOTES 1 Trying to define a Translator word that already exists will cause an error message to be displayed briefly That Translator word will retain its original definition IEEE 488 PROGRAMMING 2 A Translator word cannot exceed 31 characters 3 The Translator buffer can hold approximately 100 18 character Translator words 4 The character X and cannot be used in Translator words 5 The Model 199 will not recognize an undefined Translator word sent over the bus 6 A valid Translator word sent over the bus while the in strument is in the OLD mode will not be recognized However the instrument will try to execute on the next X the letters and numbers of the word as if they were device dependent commands To avoid this problem it is recommended that NEW be sent before trying to execute Translator words See paragraph 3 10 3 for an explanation of NEW and OLD 7 Translator error messages are listed and described in Tabie 3 14 8 Translator error numbers correspond to the U1 error word bit positions see Figure 3 9 9 lt gt lt LF gt sequence must terminate any translator execution string for proper execution Most controllers do add the necessary terminator automati cally bu
209. nel 1 of the scanner is connected directly to the signal generator while channels 2 through 8 of the scanner are connected to the amplifier outputs The gain of each amplifier is given as follows Vour Vin Thus the ratio mode of the Model 199 1992 can be used to compute the gain of each amplifier automatically COMMENTS _ Set 199 to default conditions Ohms function 30k range GET trig Store data every second Prompt for 2 or 4 pole Input mode prompt Check response limits Set number of readings depending number of poles Define O mode parameter Program step mode limit Program pole ratio mode SRQ when data store is full Number of readings in data store Prompt to begin data storage Trigger 199 to scan and store readings Get 488 bus status Wait for SRQ Clear SRQ Data store reading stop scan Get channel 1 reading Loop for all remaining channels Get ratio reading from 199 Compute and display percent tolerance of resistor Loop back for next channel Example Program The example program below can be used to run the amplifier tests described above In order to use this pro gram proceed as follows 1 Enter the program and check it for errors 2 Make certain the primary address of the Model 199 is set to 26 3 Connect the equipment together as shown in Figure 3 2 4 Set the signal generator to the desired test frequency 300kHz and amplitude
210. nel limit of 8 with the SCANNER key 5 Press SHIFT dB to select the dB function 6 Set the signal generator to the desired amplitude and mid band frequency for example 1 2 7 Press ZERO and then TRIGGER to store the OdB reference value The display should now show 0 00dB on channel 1 8 Lower the generator frequency until the Model 199 displays 3 04 The present generator frequency is the lower half power or 3dB response point 9 Raise the generator frequency above the mid band point until the display again reads 3dB The generator frequency now represents the upper half power or 3dB response point of the amplifier 10 Press TRIGGER to advance the channel 1 Repeat steps 7 through 10 for the remaining channels 2 11 12 Low level Measurement Considerations The relay contacts of the Model 1992 Scanner Card have low thermal characteristics offset allowing the card to be used for low level measurements The following paragraphs discuss methods to minimize the effects of potential error sources Thermoelectric Potentials Thermoelectric potentials thermal are small elec tric potentials generated by differences in temperature at the junctions of dissimilar metals Such thermoelectric potentials can seriously degrade low level measurement accuracy For example a copper to copper oxide junction may generate up to 10004V C while a clean copper to copper junction will typically generate
211. nnel 1 and then computes the ratio for the remain ing channels as follows 488 PROGRAMMING CHn R Where R ratio CHn channel number 2 through 8 1 channel 1 The result is then sent over the bus as requested or stored in the data store buffer if enabled Ratio values are iden tified with the RAT prefix in the data string which is discussed more fully in paragraph 3 9 12 Upon power up or after a DCL or SDC the O0 2 pole mode will be in effect Programming Example Enter the statements below to program the unit to operate in the 4 pole mode REMOTE ree QUTFUT Fee 5 01X 3 12 3 Reading interval and Delay Programming The programmed reading interval determines the time period between channels in the step mode and the time period between sets of channels in the scan mode Inter val is programmed with the Q command as follows 00 Default interval 175msec SELECT ON Qn User programmed interval Here n is the interval time in milliseconds with an allowable range of 15 to 999 999msec The factory default value for interval is 175msec The instrument will assume that value upon power up or after a DCL or SDC A channel settling time can be programmed by using the delay W command When a scan delay is used the in strument will wait the programmed delay period after clos ing a channel before taking a reading Thus the delay period acts as achannel settling time to al
212. nput LO 500 2 AC Valtage B After allowing sufficient time for the calibrator cur 8 es Calibrator rent to settle send the following command over the Model 2500E 7 Model 5200A bus V30E 3XCOX Input HI C Set the current calibrator to output 3 00000mA at 500 2 D After allowing sufficient time for the calibrator cur rent to settle send the following command over the bus V3E 3XCIX Both calibration constants will automatically be stored in E Repeat steps A through D for the remaining ACA 6 5 DISASSEMBLY INSTRUCTIONS range using Table 6 9 as a guide Figure 6 9 AC Current Calibration Configuration If it becomes necessary to remove or replace a component use the following general procedure to disassemble the NOTE unit using Figures 6 10 and 6 11 as a guide Note that the After completing the calibration procedure place Joad be carried out in ihe sequence given the unit in the CAL LOCKED state by pressing here as each step depends on completion of the prior step in on the CAL LOCK switch Also it is good idea Reassemble the unit in the reverse order For units not to place a dated calibration sticker over the switch equipped with the optional Model 1992 Scanner bypass access hole step 2 MAINTENANCE 1 N WARNING To prevent a possible shock hazard disconnect the line cord and all test leads from the Model 199 before beginning disassembly Case cov
213. nt to temporari hold up bus operation when it receives the X character until it processes all commands sent in the command string The purpose of the hold off is to ensure that the front end FETs and relays are properly configured before taking a reading Keep in mind that all bus operation will cease not just activity associated with the Model 199 The advantage of this mode is that no bus commands will be missed while the instrument is processing commands previously received The hold off period depends on the commands being pro cessed Table 3 12 lists hold off times for a number of dif ferent commands Since a NRFD hold off is employed the handshake sequence for the X character is complete NOTE With K1 asserted hoid off will also occur on an EOI and a terminator These delays allow for proper operation of the Translator software since X cannot be used in Translator words Programming Example Io program the instrument for the K2 mode enter the following statements into the computer REMOTE 7265 7 BUTPUT When the second statement is executed the instrument will be placed in the K2 mode In this mode EOI will still be transmitted at the end of the data string but the bus hold off mode will be disabled 3 24 IEEE 488 PROGRAMMING Table 3 12 Bus Hold off Times Typical Typical Hold Off Time 1l76msec 105msec 160msec 49msec 58msec 1 15
214. nter the program below to enable data store operation and obtain and display 100 readings on the computer CRT PROGRAM COMMENTS 14 DIM AF 25 28 REMOTE OUTPUT 726 ii TZQZOBI LGAN TRIGGER 226 SB 726 Send remote enable Set trigger mode and storage parameters Start storage process Set read mode to data i store FOR 1 1 T0 198 Set counter for 100 loops ENTER Get a reading PRINT Display reading I Loop back for next reading iut ERD After entering the program press the RUN key The pro gram will set the store size to 100 line 30 enable the data store line 40 turn on the data store output line 50 and then request and display all 100 readings lines 60 100 3 9 10 Value V and Calibration C One advanced feature of the Model 199 is its digital calibra tion capabilities Instead of the more difficult method of adjusting a number of potentiometers the user need on ly apply an appropriate calibration signal and send the calibration value over the bus The V command is also used to program a zero value see paragraph 3 9 4 The value comunand may take on either of the following forms Vnn nnnnn Vn nnnnnnE n Thus the following two commands would be equivalent V30 V3 0E 1 In this example note that only as many significant digits as necessary need be sent In this case the exact value is assumed to
215. nual DIRECTIONS 1 From the front panel set the primary address of the Model 199 to 26 2 With the power off connect the Model 199 to the IEEE 488 interface installed in the IBM computer 3 Type in the program lines shown below using the return key after each line 4 Run the program and type in the desired command string at the command string prompt For example to place the instrument in the ACV function and autorange type in and press the return key 5 The instrument reading string will then appear on the computer screen typical example is NACV 0 000000E 0 SEAS ek PROGRAM uu COMMENTS 18 DEF 22 segment address to C400 hex INIT 8 SEND 9 ENTER 21 _ Define call offsets ADDRESSx 21 CONTROLLER Define interface parameters ADDIREZZZX 26 DM Set 199 address to 26 TA CALL IHITCOM AIIRESSA Initialize 488 CONTROLLERS BB IHPUT COMMAHB ZTRIHG O Prompt for command string 65 D D DLHRECIZ NU Add CR to string 7B CALL SEHDCAIDREZSX CE STATUES Send command string to 199 SE RS SPACESCSS 7 _ Dimension reading input string CALL EHTERCRE LEHGTHX s ADDRESS s Get reading string from 199 STATUS 188 PRINT Display reading string 16 118 GOTO m i Repeat NOTES 1 To convert from a string to a numeric variable modify the program as follows RES 5 1223 185
216. oma wno 000000 0 0 0 CAL QQQQQQ S T WWWWWW Y Z SW SCANNER FILTER P O FILTER DISABLED 12INTERNAL FILTER ENABLED 2 INTERNAL AND FRONT PANEL FIETER ENABLED READING INTERVAL Q nnnnnn iNTERVAL 15 999999msec RANGE DCV ACV DCA ACA OHMS ACV dB dB Auto Auto Auto Auto Auto Auto 30mA 30mA 300 0 Auto Auto A 3 Auto Auto 30 A 30 Auto Auto 300 300 Auto Auto A A A t OW 300 Auto Auto 306 300 300M2 Auto Auto RATE S 4 DIGITS 1 5 DIGITS Integration Period 4 4 2 59 5 5 d Line cycle TRIGGER T O CONTINUOQUS ON TALK 1 ONE SHOT ON TALK 2 CONTINUOUS ON GET 3 ONE SHOT ON GET 4 CONTINUOUS ON X 5 5 ON X 6 CONTINUOUS ON EXTERNAL TRIGGER 7 ONE SHOT ON EXTERNAL TRIGGER TRIGGER DELAY W nnnnnn Omsec to 999999msec TERMINATOR Y O CR LF 1 LF CR 2 CR 3 LF ZERO 2 OzDISABLED 1 ENABLED CALIBRATION SWITCH O DISABLED 1 ENABLED SCANNER PRESENT O NOT INSTALLED 1 INSTALLED Figure 3 8 00 Machine Status Word and Default Values 3 26 1 TRIGGER OVERRUN 1 INTERVAL OVERRUN 199 0 1 0 1 1 BIG STRING 1 UNCAL 1 SCANNER 1 CHAN 4 1 CHAN 8 1 CAL LOCKED 1 CONFLICT 1 TRANSERR 9 1 REMOTE 1 0 1 0 1 od o on 0 1 IEEE 488 PROGRAMMING 12 TRANSERR23
217. on is intended for use by qualified personnel having a basic understanding of analog and digital circuitry The in dividual should also be experienced at using typical test equipment as well as ordinary troubleshooting procedures The information presented here has been written to assist in isolating a defective circuit or circuit section Isolation of the specific component is left to the technician Note that schematic diagrams and component location draw ings which are an essential aid in troubleshooting are located at the end of Section 7 Once the device is installed on the PC board it is nor 6 7 1 Recommended Test Equipment Success in troubleshooting complex equipment like the Model 199 depends not only on the skill of the technician but relies on the use of accurate reliable test equipment Table 6 10 lists the equipment recommended for trouble shooting the Model 199 Other equipment such as logic analyzers and capacitance meters could also be helpful especially in difficult situations 6 7 2 Power Up Self Test Upon power up the instrument will do a number of tests on itself Tests are performed on memory ROM RAM and EPROM Whenever one of the memory tests fails the instrument will lock up and must be repaired If all the tests pass then the frequency will be displayed Im mediately after turning on the Model 199 the following sequence will take place 1 A digital check will be performed on the ROM circu
218. on contains information on programming the Model 199 over the IEEE 488 bus Detailed instructions for all programmable functions are included however infor mation concerning operating modes presented elsewhere is not repeated here Additional IEEE 488 information is provided in the appendix Section 3 contains the following information 3 2 Shortcut to IEEE 488 Operation Gives a simple step by step procedure for eee on the bus as quickly as possible 33 Connections Shows typical methods for con necting the instrument to the bus 3 4 Interface Function Codes Defines IEEE standard codes that apply to the instrument 35 Primary Address Selection Tells how to program the instrument for the correct primary address 3 6 Controller Programming Demonstrates simple programming techniques for a typical TEEE 488 controller 37 Front Panel Aspects of 488 Operation Describes the operation of the bus status indicators and summarizes front panel messages that may oc cur during bus operation 38 General Bus Command Programming Outlines methods for sending general bus commands to the instrument 3 9 Device Dependent Commands Contains descrip tions of most of the programming commands used to control the instrument over the bus 3 10 Using the Translator Mode Describes an alternate programming method of using easily recognized user defined words in place of device dependent commands 3 11 Bu
219. onal shield Figure 2 5 Four Terminal Resistance Measurements Notes 1 Table 2 3 shows the current output for each resistance range 2 It helps to shield resistance greater than 100kQ anytime 472 digit resolution is used to achieve a stable reading Place the resistance in a shielded enclosure and electrically connect the shield to the LO input terminal of the instrument 3 Diode Test The 3kQ range can be used to test diodes as follows __ A Select the range B Forward bias the diode by connecting the red ter minal of the Model 199 to the diode anode A good diode will typically measure between 3000 and 1kQ C Reverse bias the diode by reversing the connections on the diode A good diode will overrange the display Table 2 3 Resistance Ranges Maximum Test Lead 5d Nominal Resistance 0 for Resolution I Short lt 1 Count Error 524 NOTE Typical open circuit voltage is 5 54 2 11 BASIC OPERATION 2 6 7 TRMS AC Voltage Measurements The instrument can make TRMS AC voltage measurements from 14V to 300V To measure AC volts proceed as follows 1 Select the AC volts function by pressing the VOLTS and AC buttons 2 Select a range consistent with the expected voltage or use autorange 3 Select the front or rear panel input terminals using the INPUT switch NOTE There is a small amount of offset typically 150 counts at 542d present when using the ACV f
220. onding TRMS Meter Peak Percent Waveform Value ing ing Error Half Wave Rectified Sine TIO ay 0 Full Wave Rectified Sine 10 0 OAO Square Rectified Square Wave TE 0 Rectangular Pulse x100 K 10 jp Y 0 Triangular Sawtooth MA 2 15 BASIC DMM OPERATION 2 6 11 dB Applications Measuring Circuit Gain Loss Any point in a circuit can be established as the 0dB point Measurements in that cir cuit are then referenced to that point expressed in terms of gain dB or loss dB To set the zero dB point pro ceed as follows 1 Place the Model 199 in AC volts and dB 2 Connect the Model 199 to the desired location in the circuit 3 Press the ZERO button The display will read OdB 4 Gain loss measurements can now be made referenced to the OdB point Measuring Bandwidth The Model 199 can be used to determine the bandwidth of an amplifier as follows 1 Connect a signal generator and a frequency counter to the input of the amplifier 2 Set the Model 199 to AC volts and autorange 3 Connect the Model 199 to the load of the amplifier 4 Adjust the frequency of the signal generator until a peak AC voltage reading is measured on the Model 199 This is the center frequency 5 Press SHIFT dB button and then press the ZERO but ton The 0dB point is now established 6 Increase the frequency input until the Model 199 reads 3 00dB The f
221. ont panel operation by pressing the LOCAL button 3 8 2 IFC Interface Clear The IFC command is sent by the controller to place the Model 199 in the talker and listener idle states The unit will respond to the IFC command by cancelling TALK or LISTEN if the instrument was previously placed in one of those modes To send the IFC TT the controller need ol set the IFC line true for a minimum of 100 Table 3 6 General Bus Commands and Associated BASIC Statements REMOTE 7 ABORT LOCAL LOCKOUT 7 LOCAL CLEAR CLEAR 725 TRIGGER 7 3 10 BASIC 4 0 T Command Statement Affect on Model 199 Go s into remote when next addressed Goes into talker and listener idle states Front LOCAL key locked out Cancel remote Returns to default conditions Returns to default conditions Triggers reading in T2 and T3 modes IEEE 488 PROGRAMMING 3 8 3 LLO Local Lockout The LLO command is used to lock out operation of the LOCAL key thereby completely locking out front panel operation of the instrument recall that the remaining con trols are locked out when the instrument is placed in remote To send the LLO command the controller must perform the following steps 1 Set ATN true 2 Place the LLO command byte on the data bus To cancel local lockout and return control to the front panel REN must be set false by sending the LOCAL 7 command to the instrument
222. or Test Connections 2 29 BASIC DMM OPERATION 2 11 2 Scanner Display Format The front panel display format is similar to normal display format with one important exception The channel number appears in the right most digit of the display while the scanner is operating The selected measuring function will also appear on the display except when on channels 2 through 8 while in the ratio mode The ratio mode is discussed in detail in paragraph 2 11 5 2 11 3 Pole Mode Programming As discussed in paragraph 2 11 1 the 2 pole mode is in tended for use with volts and 2 wire ohms measurements while the 4 pole mode is designed for use with 4 wire resistance measurements For proper operatio n the pro grammed pole mode must agree with the pole configura tion discussed in paragraph 2 11 1 The pole mode can be programmed by using the SCAN SETUP key as outlined below 1 Press SHIFT SCAN SETUP to display the pole mode For the 2 pole mode the display will appear as follows 2 POLE 2 For the 4 pole mode the display shows 4 POLE 3 Use uprange or downrange as necessary to toggle the pole mode to the desired status 4 Once the desired pole mode is selected press NEXT once to advance to the next menu selection ratio or press NEXT three times to return to normal display NOTE A CHAN 4 error will occur if you attempt to select the 4 pole mode with a channel limit greater than four 2 11 4 Ratio Mode
223. or downrange to select the continuous trigger mode then press NEXT and set the trigger delay to the desired value 4 Press NEXT then use uprange or downrange to choose SELECT OFF 175msec or SELECT ON user programmed data store interval then press NEXT 5 For select interval only enter the desired data storage interval in the range of I5msec to 999 999sec For ex ample to enter a one second interval press 00100 0 then press NEXT to complete interval programming 6 Press SHIFT STORE to enter data store mode The in strument will display the programmed data store size 000 SIZE The size value determines how many readings will be stored up to a maximum of 500 before the storage cycle stops However a size of 000 indicates that the storage cycle will continue even after all 500 readings are stored After the 500th reading is stored readings will be stored begin ning at the first memory location overwriting the previous ly stored data 7 Key in the desired number of readings use 000 for wrap around storage then press the NEXT key to program that value STO will flash on to indicate the unit is waiting for a trigger eS SS 2 22 8 Press TRIGGER to initiate storage The instrument will begin storing data at the programmed interval While storage is active you can display the most recently stored location by entering the recall mode see 2 10 3 9 After all readings have been store
224. or making DC volts AC volts and two wire resistance measurements AMPS AMPS is used in conjunction with LO to make DC current and AC current measurements OHMS SENSE and LO These terminals are used with VOLIS OHMS HI and LO to make four wire resistance measurements 2 4 REAR PANEL FAMILIARIZATION The rear panel of the Model 199 is shown in Figure 2 2 The various items located on the rear panel are discussed SCANNER MAX TERMINAL TO TERMINAL VOLTAGE 200V PEAK ANY TERMINAL TO EARTH 350V PEAK WARNING USER SUPPLIED LETHAL VOLTAGE PRESENT ON SCANNER CONNECTORS DISCONNECT LINE CORD INPUTS AND OUTPUTS BEFORE SERVICING EXT TRIGGER METER COMPLETE OUTPUT INPUT MADE IN U S A LINE FUSE SLOWBLOW LINE VOLTAGE SELECTED 90 125 180 250V 620225555 ld 90 110VE 180 220 105 125V 210 250 O 20VA 50 60 2 AC ONLY MIGA 90 125 1 104 190 250 Figure 2 2 Model 199 Rear Panel 2 5 BASIC DMM OPERATION 2 4 1 Connectors and Terminals Input terminals The rear panel VOLTS OHMS and OHMS SENSE terminals perform the same func tions as the equivalent front panel terminals Voltage and two wire resistance measurements are made using the VOLTS OHMS terminals while four wire resistance measurements are made using both the OHMS SENSE and VOLTS OHMS terminals EXTERNAL TRIGGER INPUT This BNC tor is used to apply negative going TTL compa
225. orange can be used with data store 2 Press SHIFT TRIG SETUP and then select the one shot trigger mode by pressing uprange or so the following is displayed T ONE SHOT 3 Press NEXT and program the desired trigger delay Press NEXT note that dashes remain in the display because the instrument has yet to be triggered um BASIC DMM OPERATION 4 Press SHIFT STORE to enter the data store the unit will display the programmed size 000 SIZE Key i in the desired number of to store e 1500 or select a size of 000 for wrap around storage Press NEXT to complete programming The STO light will then flash to indicate the instrument is waiting for a trigger 6 Press the TRIGGER button to trigger the unit or apply a trigger pulse to the unit see paragraph 2 9 1 A single reading will be processed and stored with each trigger stimulus _ NOTES 1 Data can be recalled during the storage process as described in paragraph 2 10 3 2 To disable data store and return to normal operation press any function key If recall is also enabled you must first press NEXT to cancel recall and then press any func tion key 3 The RCL indicator will flash on when all programmed readings have been stored except in continuous 4 TRIGGER OVERRUN error will occur if the unit is triggered while processing a reading from a previous trigger The current reading will not be aborted and the error t
226. ord If ROM and RAM fails the instrument will lock up See paragraph 6 7 2 for more information on these tests and recommendations to resolve a failure ing Example Enter the following statements in to the computer to perform the Model 199 self test REMOTE 72 OUTPUT 726 Jays When the END LINE key is pressed the second time the instrument performs the self test If successful the self test byte J in the U0 status word will be set to 1 3 9 20 Hit Button H _ The hit button command allows the user to emulate vir tually any front panel control sequence The H command is sent by sending the ASCII letter followed by a number representing a front panel control These control numbers are shown below Command Button HO VOLTS H1 OHMS H2 AMPS H3 AC H4 ZERO H5 AUTO H6 v H7 A H8 SCANNER H9 TRIGGER 10 SHIFT Examples HOX Selects the VOLTS function 2 the AMPS function Programming Example Enter the following statements in to the computer to place the instrument in the ohms function The instrument is placed in the ohms function 3 29 IEEE 488 PROGRAMMING 3 9 21 Display 0 The display command controls the ASCII messages that can be placed onto the Model 199 display controlled with the following commands Da Display character where represents
227. ore make The time required to change channels is approximately 17msec which includes break before make relay time settling time When using the scanner with or a DELAY time must be ed to accomodate AC converter settling time typically gt 16 See Model 199 specifications The scanner operates with the set of instrument parameters program med prior to start of scanning Changing any of these parameters range function filter etc during scanning will restart the scanner at chan nel 1 Use autorange if range changes are required while scanning USING SCANNER WITH DATA STORE Select desired scanner parameters and interval Activate scanning SCANNER channel limit Program data store size TRIGGER will start data store and automatically restart scanning at chan nel 1 synchronized with data store location 1 EXAMPLE OF FAST SCANNING 1 Select DC range and function 4 digit resolution off 2 Program ONE SHOT trigger 3 Select SCAN mode 4 Select SCANNER 8 to set limit to 8 5 Use TRIGGER to initiate a scan of the set of eight channels 4 199 IEEE 488 Programming DEVICE DEPENDENT COMMANDS EXECUTE X Execute other device dependent commands FUNCTION FO DC volts FI AC volts F2 Ohms F3 DC current F4 AC current F5 ACV dB F6 ACA dB RANGE ACA ACV DCA ACA Ohms dB dB Auto Auto Auto RO Auto Auto Auto Auto Ri 300mV 300mV 30m
228. ork Q13 and Q3 off and applied directly to the multiplexer through K1 and Q30 AC Volts The basic steps involved in ACV conditioning are as follows 1 Relay applies the ACV input to the gain circuitry Here the signal undergoes a gain factor of 10 300mV range 1 range 1 10 30V range or 1 100 300V range 2 The signal is then applied to the TRMS converter U27 where the AC signal is converted to a DC signal 3 The DC signal is then applied to the multiplexer On the 300mV and ranges the signal is routed through relay K5 and buffer U28A On the 3V range the signal pro ceeds through analog switch U21C and buffer U26B before being applied to the TRMS converter U27 On the 300mV range the signal is detoured through analog switch U23A to U28B which is configured as a X10 amplifier The amplified signal then proceeds through analog switch U23B and buffer U26B to the TRMS converter U27 5 1 PRINCIPLES OF OPERATION On the 30V range the signal is applied to U26A Because analog switch U21A is open on this range amplifier U26A has a feedback resistance of R32 which results in a gain factor of 1 10 The divided signal is then routed through analog switch U21B and buffer U26B to the TRMS converter U27 input Conditioning Current Shunts ACA AC Attenuation AC DC Conversion On the 300V range the signal is applied to U26A Because a
229. ot be used as defin ed Translator words These reserved words and character make up the Translator software syntax and are listed in Table 3 13 Table 3 13 Translator Reserved Words and Character Used at the beginning of a command string to define Translator words Used to terminate the Translator string one space must precede it Used to define wild card Translator words Values sent with a wild card Translator word select options of the equivalent DDC Tells the Model 199 to recognize Translator words Tells the Model 199 to only recognize the cd commands Saves Translator words as power up default Used to list the Translator words Used to purge Translator words from memory 3 30 pe 3 10 1 Translator Format The basic format for defining a Translator word is shown in the following example command string which defines the word SETUP as a substitute for FIROX ALIAS SETUP1 FIROX Where A ALIAS is a reserved word that precedes the Translator word SETUP is the desired Translator word FIROX is the Keithley command string 15 a reserved character necessary to terminate the Translator string spaces must be used to separate words and the character DA When SETUP1 is sent over the IEEE 488 bus the instru ment will go to the ACV function F1 and enable autorange RO Translator words that contain conflicting device dependent commands such as F and F2 can be defi
230. ould follow each command with the execute character X as in the example string LOXF2X which will reset the instrument to factory default conditions and then select the ohms function Device dependent commands can be sent either one at a time or in groups of several commands within a single string Some examples of valid command strings include FOX Single command string FOKIPOROX Multiple command string T6 X Spaces are ignored Typical invalid command strings include E1X Invalid command as E is not of the instrument commands Fi5X Invalid command option because 15 is not an option of the F command If an illegal command IDDC illegal command option IDDCO is sent or if a command string is sent with REN false the string will not be executed Device dependent commands that control the Model 199 itself are listed in Table 3 8 Scanner programming is covered separately in paragraph 3 12 These commands are covered in detail in the following paragraphs The associated programming examples show how to send the commands from BASIC 4 0 488 PROGRAMMING Notes In order to send device dependent command the con troller must perform the following steps 1 Programming examples assume that the Model 199 is at its factory default value of 26 1 Set ATN true 2 Device dependent commands sent over the bus while 2 Address the Model 199 to listen the unit is in a front panel menu will be i
231. over the bus 190 C Set the resistance calibrator to SHORT 00 D After allowing sufficient time for the resistance calibrator to settle send the following command over the bus VOXC1X Both calibration constants will be automatically stored in E7PROM MAINTENANCE Repeat steps A through D for the remaining ohms ranges using Table 6 6 as a guide L4 Resistance Sense Li sense Calibrator T Sense LO 1 9 Model 5450A Output LO Shielded Cable MODEL 199 _ Figure 6 3 Four Wire Resistance Calibration Configuration 3000 30kO0 Ranges Resistance Calibrator Model 5450A d Figure 6 4 Two Wire Resistance Calibration Configuration 300k0 300MO Ranges 67 MAINTENANCE Table 6 6 Resistance Calibration 6 4 10 TRMS AC Volts Calibration A full calibration of the ACV function includes two inter nal manual adjustments However if high frequency is checked and found to be within specifications the inter nal adjustments on the 30VAC and 300VAC ranges will not have to be done The following procedure includes these checks The flowchart in Figure 6 5 helps clarify the calibra tion procedure NOTE For front panel calibration omit step 4 of the following procedure For IEEE 488 bus calibration omit step_3 _ 1 Select the ACV function and the 300mV range 2 Connect the AC calibrator as shown in Fig
232. ph 3 9 16 An explana tion of each error can also be found in paragraph 3 9 16 Bit 6 ROS Provides a means to determine if an SRQ was asserted by the Model 199 If this bit is set service was requested by the instrument Bit 7 Not used and always set to zero Note that the status byte should be read to clear the SRO line once the instrument has generated an SRQ All bits in the status byte will be latched when the SRQ is generated Bit 6 ROS will be cleared when the status byte is read 488 PROGRAMMING Programming Example Enter the following program in to the computer PROGRAM COMMENTS 18 REMOTE 726 Set up for remote operation 15 CLEAR rae 26 OUTPUT Program for SRQ on IDDCO 28 OUTPUT Attempt to program illegal option 4B S SPOLLC7 265 Serial poll the instrument 45 IF 2176 5 2 48 Wait for SRO error SH 4 Identify the bits FOR STEP 1 Loop eight times FH BIT 65 175 Display each bit position SH HEST I PRINT 188 Once the program is entered and checked for errors press the RUN key The computer first places the instrument in remote line 10 and then programs the SRO mode of the instrument line 20 Line 30 then attempts to pro gram an illegal command option at which point the in strument generates an
233. plug the con necting blocks Remove the shorting jumpers from the channel inputs Assuming the scanner card functioned normally the unit is now reading for use 6 8 3 Relay Shieid Jumper A jumper W1 on the scanner board is factory installed MODEL 199 REMOVE REAR COVER PLATE 6 24 to connect the relay shields to analog ground see Figure 6 13 If desired this jumper can be cut to float the shields or to connect another potential for example for guarding CAUTION Maximum voltage between shields and contact is 250V DC MAINTENANCE P1 J26 Scanner Connection Cut Jumper Scanner WS for Scanner i Operation Jumper cut to float relay shieids Route Ribbon Cable Under Scanner Board Digital Board Jumper W2 shown installed in position B 2 Conductor cable Figure 6 13 Scanner Connector Location 6 25 6 26 SECTION 7 7 1 INTRODUCTION This section contains replacement parts information com ponent location drawings and schematic diagrams for Model 199 7 2 PARTS LIST Parts are listed alphanumerically in order of their circuit designations Table 7 1 contains parts list information for the display board Table 7 2 contains parts list information for the digital board Table 7 3 contains parts list informa tion for the analog board Table 7 4 contains a miscel laneous parts list for the Model 199 Model 1992 parts are
234. points on the connec tor pins Front panel and display board removal Disconnect the five wires going from the front panel input jacks to the analog board B Carefully pry the locking tabs free of the front panel rails then remove the front panel C Remove the screws that secure the top and bottom rails to the right case sides then remove the rails D Grasp the display board by the edges and remove the board by pulling it forward until it is clear of the analog board tab 5 Analog board removal Remove the two screws that secure the rear panel to the case right side As the screws are removed remove case side B Remove the nut that secures the green ground wire to the rear panel Disconnect the four rear panel input jack wires D Remove the two nuts that secure the AC receptacle 27 to the rear panel then remove the rear panel from the analog board WARNING When reassembling the unit the green ground wire must be securely connected to the rear panel to ensure continued protection against possible shock hazards MAINTENANCE ul z lt e e lt a DIGITAL BOARD 199 CASE Figure 6 10 199 Exploded View 6 15 P1 J26 Scanner Connection Rear Install Jumper to Connect Digita Common to Chassis Ground Digital Board P15 J15 To Trigger Jacks Analog Board J14 To Display eeoccene Board
235. program the unit to generate an SRQ when the data store is half full or completely full M2 or M4 Program the in strument for data store output by sending BIX and then request data in the usual manner If buffer locations and channel numbers are required use the G6 or G7 data format Programming Example The program below demonstrates basic data store opera tion with the scanner The program sets up the instrument for DCV 3V range 2 pole mode with eight channels The unit is also set up to store one channel per interval the interval is programmed for a value of one second The total number of readings is set to 80 which will accommodate ten sets of scanner data at eight channels per set The program comments on each line are self explanatory 488 PROGRAMMING PROGRAM c 18 REMOTE 725 za 251 28 5 SP GREE DCV 3V range 48 OUTPUT FZE Select 2 pole mode QUTPUT Fee HISETT One channel per OUTPUT 726 OUTPUT 725 E OUTPUT OUTPUT 72 5 3 amp iiie COMMENTS Put 199 in remote Dimension reading input string store interval One second data store interval Continuous GET trigger mode Store 80 readings in data store when data store is full TRIGGER 726 Trigger 199 118 S SPOLL 47257 Get IEEE 488 bus status 12
236. put shorted This offset is caused by the offset of the TRMS converter This offset will not affect reading accuracy and should not be zeroed out using the zero feature The following equation expresses how this offset V y is add ed to the signal input V Displayed reading V Va 2 Offset 150 counts 1 5mV Input 200mV RMS Sm 004V 2 25 x 10 V 200005V Display reading The offset is seen as the last digit which is not displayed Therefore the offset is negligible If the zero feature were used to zero the display the 150 counts of offset would be subtracted from V resulting in an error of 150 counts in the displayed reading Crest Factor The crest factor of a waveform is the ratio of its peak value to its RMS value Thus the crest factor specifies the dynamic range of a TRMS instrument For sinusoidal waveforms the crest factor is 1414 For a sym metrical square wave the crest factor is unity 2 14 BASIC DMM OPERATION The crest factor of other waveforms will of course depend Where T period on the waveform in question because the ratio of peak to t pulse width RMS value will vary For example the crest factor of a pulse is computed as follows E t This relationship holds for all pulse waveforms Table 2 5 Comparison of Average and TRMS Meter Readings Average AC Coupled Averaging Coupled Resp
237. r calibrating the instru ment over the IEEE 488 bus The detailed calibration pro cedure starts with paragraph 6 4 7 Use the following basic procedure when calibrating the Model 199 over the IEEE 488 bus 1 Place the unit in the CAL UNLOCK state The CAL LOCK switch is accessed from the front panel of the Model 199 2 Program the desired range and function over the bus For example to select the 300V DC range send FOR4X Program zero off and 57 digit resolution by sending 2051 4 The high end of the range is calibrated first Apply full range or near full range calibration signal to the input of the instrument For example for the 300V DC range apply 300V DC to the instrument 5 Send the required calibration value preceded by the V command letter and followed by the first calibration command A For DCV ranges send C2 first For example send V 300XC2X B For all other functions send first For example send V300XCOX NOTE Calibration can be aborted at this time by sen ding an SDC DCL command over the bus The calibration constant sent in step 4 will not be stored in 6 The low end of range is calibrated next Apply zero or near zero calibration signal to the input of the in strument For example for the 300V DC range apply 0V _ to the instrument 7 Send the appropriate calibration commands for the sec ond or third with DCV calib
238. r isolation The analog section consists of the signal conditioning cir cuits multiplexer input amplifier A D converter and con trol circuitry The heart of the digital section is 68B09 microprocessor that supervises the entire operation of the instrument Additional digital circuitry includes the display and IEEE 488 interface If the optional Model 1992 Scanner is installed it is con trolled through the control circuits located on the analog board Connections to the DMM inputs are supplied by the user 5 3 ANALOG CIRCUITRY The detailed circuitry of the Model 199 analog section is located on schematic diagram number 199 126 5 3 1 input Signal Conditioning Signal conditioning circuitry modifies the input to a signal that is usable by the Model 199 and applies that signal to the multiplexer DC Volts Signal conditioning for the 30V and 300V ranges is per formed by resistor divider network 17 On these ranges K1 K2 and K3 are open and the divider network is con nected to signal ground through O11 and U22A The following attenuation of the input signal is provided Divided by 10 on the 30V range Divided by 100 on the 300V range On the 30V range 13 is and Q3 is off routing the in put signal in the multiplexer Q35 On the 300V range Q13 is off and Q3 is on routing the input signal to the multiplexer 035 On the 300mV and 3V ranges the in put signal is removed from the resistor divider netw
239. r will appear on the display Trigger the unit to advance to the next channel and take the subsequent reading One trigger per channel will be required after all channels up to the programmed limit have been scanned the unit will begin again with channel 1 Program a channel limit of 0 to cancel the scan mode and return to normal display To do so press SCAN NER 0 2 32 BASIC DMM OPERATION NOTES 1 The unit will display a TRIGGER OVERRUN message if it is triggered while processing a reading from a previous trigger The error trigger will be ignored 2 The Model 199 will display the CHAN 4 MAX message if you attempt to program a channel limit greater than 4 in the 4 pole mode 3 In the ratio mode channel 1 data will be displayed as the selected function while channels 2 through 8 will be displayed as the ratio 2 11 9 Scan Mode Operation In the SCAN mode the unit will scan one set of channels per programmed reading interval continuous trigger mode or one set of channels per trigger one shot trig ger mode The number of channels per sequence is deter mined by the program channel limit The following paragraphs outline the general procedures for using scan Reading Interval Operation N Select the range and function as required Press SHIFT TRIG SETUP and select the continous trigger mode with uprange or downrange Press NEXT twice to advance to the interva
240. ranges from an input current greater than 3A To replace the current fuse perform the following steps 1 Turn off the power and disconnect the power line test leads 2 Place the end of a flat blade screwdriver into the slot in the fuse holder on the front panel Press in slightly and rotate the fuse carrier one quarter turn counterclockwise Release pressure and remove the fuse carrier and the fuse 3 Remove the defective fuse and replace it using Table 6 3 as a guide CAUTION Use only the recommended fuse type If a fuse with a higher current rating is installed instru ment damage may occur y 4 replace the fuse carrier with the fuse reverse the pro cedure in step 2 Table 6 3 Current Fuse Replacement Keithley Part No 250V SAG Normal 6 4 CALIBRATION Calibration should be performed every 12 months or if the performance verification procedures in Section 4 show that the Model 199 is out of specification If any of the calibration procedures in this section cannot be perform ed properly refer to the troubleshooting information in this section If the problem persists contact your Keithley representative or the factory for further information Check that the instrument is set to the proper line frequency before proceeding with calibration The entire calibration procedure may be performed without having to make any internal adjustments if high frequency 70kHz has been
241. ranslator words The two Translator words are combined to form the word SETUP3 3 10 6 Executing Translator Words and Keithley IEEE Commands Translator words including wild card words and Keithley IEEE commands can be executed in the same command string The format for doing this is demonstrated in the following examples SETUP1 171 FUNCTION 2 P1ZIX When the first command string is sent over the bus the commands in SETUP and the Keithley IEEE commands will be executed When the second string is sent the se cond option of the wild card FUNCTION command and the Keithley IEEE commands will be executed ing Example The following program will assert the commands of an existing Translator word and the stan dard Keithley IEEE commands over the bus Tea ZETHP1PIZ X The commands of 1 and the Keithley IEEE com mands P1Z1X will be sent over the bus 3 10 7 SAVE Translator words can be remembered by the instrument as power up default words by sending the reserved word SAVE If SAVE is not sent Translator words will be lost when the instrument is turned off Reset is run or an SDC DCL or LO is sent over the bus When SAVE is sent the instrument also remembers if it was in NEW or OLD If the instrument is in NEW when SAVE is sent it will power up in NEW If the instrument is in OLD when SAVE is sent it will power up in OLD Programming Exampie With one or
242. ration point For example to calibrate the zero calibration point of the 300V DC range send Note that C1 is used for the second calibration point 8 Storage of the two calibration points into automatically occurs when the second calibration com mand is sent 9 Repeat steps 1 8 for the remaining ranges and functions MAINTENANCE Programming Example The following simple program demonstrates how to calibrate the Model 199 over the bus The program assumes that the instrument s primary ad dress is at 26 PROGRAM COMMENTS iB REMOTE 726 Send remote enable zB PRINT AFFLY Prompt for calibration CAL IBRRATIUOMH SIGHBAL EHTER signal x CALI Prompt for command BRAT ION 38 IHFLUT AS Input command string from keyboard OUTPUT 725 Send command string to 199 TH ENTER 726 EF Get a reading PRIHT Display reading GOTO 58 Loop back 18 To run the program press the RUN key At the prompt apply a calibration signal to the instrument type in the corresponding calibration command and press the return key The computer CRT will then display the calibration value 6 4 7 Calibration Sequence Calibrate the Model 199 in the order presented in the following paragraphs The basic sequence is 1 DC Volts calibration 2 Ohms calibration 3 AC Volts calibration 4 DC Current calibration 5 AC Current
243. rator To Channel L Terminals gt gt gt gt D gt 1992 CARD Figure 2 15 Amplifier Gain Test Configuration 2 35 BASIC DMM OPERATION In order to perform the gain tests the following general procedure should be followed 2 1 2 1 Connect the equipment together as shown in Figure 2 15 Assuming that AC gain is to be tested place the Model 199 in the ACV function and select a range high enough to measure the expected output voltages Press SHIFT TRIG SETUP and select the one shot trig ger mode then program a one second delay Return to normal display after programming the trigger mode and delay Press SHIFT SCAN SETUP and program the 2 pole mode Press NEXT and select the STEP scan mode with uprange or downrange Press NEXT and turn on the ratio mode by using uprange or downrange M Press NEXT to exit the scanner setup mode Press SCANNER and select a channel limit of 8 If you wish to store the amplifier gain data press SHIFT STORE and select a reading size of 8 Press NEXT to return to normal display Set the signal generator to the desired output frequency lt 300kHz and amplitude for the gain test Press TRIGGER to initiate the scan With the first trig ger the instrument will take amplifier input voltage reading on channel 1 and then store that reading as the ratio reference value Press TRIGGER to advance to channel 2 At this poin
244. readings EXTER Get reading SS AMPLIFIER Display gain value NEXT I Loop back for next reading 528 EHI 3 45 IEEE 488 PROGRAMMING Signal Generator 4 Channel Input L Terminals gt gt gt gt gt gt gt Figure 3 12 Amplifier Test Configurations 3 46 SECTION 4 Performance Verification 4 1 INTRODUCTION The procedures outlined in this section may be used to verify that the instrument is operating within the limits stated in the specifications at the front of this manual Per formance verification may be performed when the instru ment is first received to ensure that no damage or misad justment has occurred during shipment Verification may also be performed whenever there is a question of instru ment accuracy or following calibration if desired NOTE If the instrument is still under warranty less 1 year from the date of shipment and its perform ance falls outside the specified range contact your Keithley representative or the factory to determine the correct course of action 4 2 ENVIRONMENTAL CONDITIONS All measurements should be made at 18 28 C 65 82 F and at less than 8096 relative humidity 4 3 INITIAL CONDITIONS The Model 199 must be turned on and allowed to warm up for at least two hours before beginning the verfication procedures If the instrument has been subj
245. rectly suspect that the hardware is causing a problem when it was the software all along 3 6 2 BASIC interface Programming Statements The programming instructions covered in this section in clude examples written in Hewlett Packard BASIC 4 0 This computer language was chosen for the examples because of its versatility in controlling the IEEE 488 bus A partial list of statements for BASIC 4 0 is shown in Table 3 4 Statements have a one or three digit argument that must be specified as part of the statement The first digit is the interface select code which is set to 7 at the factory The last two digits of those statements requiring a 3 digit argu ment specify the primary address In the examples shown the default Model 199 address 26 is shown For a different address you would of course change the corresponding digits in the programming statement Some of the statements have two forms with the exact con figuration depending on the command to be sent over the bus For example CLEAR 7 sends a DCL command over the bus while CLEAR 726 sends the SDC command to a device with a primary address of 26 Table 3 4 BASIC Statements Necessary to Send Bus Commands Transmit string to device 26 Obtain string from device 26 Send to device 26 Send SDC to device 26 Send DCL to all devices Send remote enable Cancel remote enable Serial poll device 26 Send Local Lockout Send GET to device 85 Statement
246. requency measured on the frequency counter is the high end limit of the bandwidth 7 Decrease the frequency input until the dB reading again falls to 3 00dB The frequency measured on the signal generator is the Jow end limit of the bandwidth Note The bandwidth of the Model 199 is typically 300kHz Do not use this application to check amplifiers that exceed the bandwidth of the Model 199 Determining of a tuned circuit can be deter mined as follows 1 Determine the center frequency and bandwidth as ex plained in the previous application Measuring Bandwidth 2 Calculate Q by using the following formula Q Center Frequency Bandwidth 2 7 DMM SETUP PROGRAMS There are eight DMM setup programs available from the front panel of the Model 199 as summarized in Table 2 6 These programs are described in detail in the following paragraphs Program Selection Programs can be selected by pressing SHIFT DMM SETUP on the front panel To scroll through programs press the NEXT key Once the desired program is displayed perform the necessary operation as described below Data Entry The IEEE 488 primary address program re quires numeric data entry To enter data use the data en try keys 0 9 The cursor location for data entry is indicated by the bright flashing display digit The cursor moves right each time a number 15 entered The cursor will wrap around to the left after exiting the right most digit When
247. ressing any front panel button except TRIGGER then exit the setup mode by pressing NEXT to return to normal display Change the range or function as required then re enter the diagnostic program by using DMM SETUP 6 7 4 Power Supplies Table 6 12 shows the various checks that can be made to the power supplies of the Model 199 In addition to the normal voltage checks it is a good idea to check the various supplies with an oscilloscope for signs of noise or oscillations 6 7 5 Signal Conditioning Checks These circuits can be checked by using the diagnostic pro gram under DMM SETUP as explained in the paragraph 6 7 6 Digital and Display Circuitry Checks The digital and display circuitry can be checked out by us ing the troubleshooting data found in Tables 6 13 and 6 14 6 7 7 Scanner Checks Troubleshoot the optional Mode 1992 Scanner using Table 6 15 MAINTENANCE Table 6 11 Model 199 Troubleshooting Mode ie a Input Measurement Buffer Relays Range Switches Multiplex Rane Phase N Mode Gain Closed ECT Closed x10 300mV DC j SIG ZERO U22A CAL ZERO On U22A CAL U22A SIG U22A UD Q32 U25C Q32 Q30 SIG ZERO U22A Q34 CAL ZERO 02 QH U22A U25D Q32 CAI 03 U22A U25C 032 SIG QU U22A Q30 SIG ZERO Q13 Q11 U22A 033 CAL ZERO 02 QB U22A U25D Q32 CAL 03 013 U
248. riggers will be buffered to re trigger the unit when it is ready 2 10 3 Recalling Data Data can be recalled either during storage or after storage is complete by using the procedure below 1 Press SHIFT RECALL to display data The instrument will turn on the RCL indicator and display the location of the last stored data point for example for location 35 035 LOC 2 For sequential access use the uprange or downrange key while displaying the data value Uprange increments locations while downrange decrements locations The location will wrap around to the opposite end of the data store buffer once the lowest or highest location is accessed 3 To display a particular data location number whilei inthe recall mode press the RECALL key Press NEXT to return to normal recall data display 4 For random access to a particular location key in the location number with the data entry keys and then 2 23 BASIC OMM OPERATION press the NEXT key The unit will then display the data value at that location along with the measurement func tion in effect at the time the data was taken 5 To exit the recall mode press NEXT while normal recall data is displayed RCL will turn off to indicate that recall has been disabled NOTES 1 If data store has no valid data to display the unit will display the following message upon entry to the recall mode NO DATA 2 The unit will continue to store data while in recall until
249. rocedures included in this section are for use only by qualified service personnei Do not perform these procedures unless qualified to do so Many of the steps in this section may expose you to potentially lethal voltages that could result in personal injury or death if nor mal safety precautions are not observed 6 2 LINE VOLTAGE SELECTION The Model 199 may be operated from either 105 125V or 210 250V 50 or 60Hz power sources A special transformer may be installed for 90 110V and 190 220V ranges The in strument was shipped from the factory set for an operating voltage marked on the rear panel To change the line voltage pro ceed as follows WARNING Disconnect the line cord and all other equip ment from the Model 199 1 Place the line voltage switch located on the rear panel in the desired position See Table 6 1 for the correct position 2 Install a power line fuse consistent with the line voltage See paragraph 6 3 1 for the fuse replacement procedure CAUTION The correct fuse type must be used to main tain proper instrument protection 3 Mark the selected line voltage on the rear panel for future reference to avoid confusion erase the old mark Table 6 1 Line Voltage Selection Line Switch Voltage Setting Line Frequen 105V 125V 50Hz 60Hz 105V 125V 210V 250V 50Hz 60Hz 210V 250V 6 3 FUSE REPLACEMENT The Model 199 has two fuses for protection in case of overload The l
250. rogram other values between 0 _ 30 by pressing 199 SETUP More detailed information on primary address selection is located in paragraph 3 5 Step 3 Write Your Program Even the most basic operations will require that you write a simple program to send commands and read back data from the instrument Figure 3 1 shows a basic flow chart that a typical simple program will follow The program ming example below follows this general sequence This program will allow you to type in command strings to pro gram the instrument and display data on the computer HP BASIC 4 0 Programming Example Use the simple rogram below to send programming commands to the Model 199 and display the data string on the computer CRT PROGRAM COMMENTS 18 REMOTE 72 amp Send remote enable 28 PRINT COMMAHD Prompt for command string 28 Input the command string 4B OUTPUT 726 Send command string to 199 58 ENTER 726 AF Get a reading from instrument 28 PRINT Display the needling GOTO Repeat eu Place Unit in Remote Program Operating Modes Request Data From 199 Display Data Figure 3 1 Typical Program Flow Chart Step 4 Program Model 199 Operating Modes You can program instrument operating modes by sending the appropriate command which is made up of an ASCII letter representing the command followed by a numeric parameter for the comma
251. s Programming Example To demonstrate an IDDC error use the following statements REMOTE T26 OUTPUT Fee SP E1X Note that the IDDC error message is briefly displayed when the second statement above is executed IDDCO Illegal Device Dependent Command Option Error _ Sending the instrument a legal command with an illegal option will result in the following front panel error message IDDCO For example the command Y9X has an illegal option 9 that is not part of the instrument s p ing language Thus although the command Y itself is valid the op tion 9 is not and the IDDCO error will result To avoid this error condition use only valid command op tions as discussed in paragraph 3 9 Programming Exampie Demonstrate an IDDCO error with the following statements REMOTE 25 OUTPUT 726 3 8 IEEE 488 PROGRAMMING Note that the IDDCO error message is briefly displayed when the second statement above is executed Trigger Overrun Error A trigger overrun error occurs when the instrument receives a trigger while still processing a reading from a previous trigger Note that any overrun triggers are ig nored These overrun triggers will not affect the instru ment except to generate the message below When a trig ge overrun occurs the following front panel message w e displayed for approximately one second TRIGGER OVERRUN Programming Example lo demonstrate a trigger overr
252. s Control Feature Default Condition Function DCV Range 300V Resolution 5 Digits Zero Off dB Off Filter Off Multiplexer On IEEE 488 Primary Address 26 60Hz 175msec select off Continuous Line Frequency Trigger Delay Reading Interval Trigg r Mode Data Store Off Polest 2 Ratiot Off Scan Modet Manual These modes can be altered by using save setup TWith optional 1992 scanner User Saved Default Conditions Each function of the Model 199 remembers the last 2 2 measurement configuration that it was set up for such as range zero value etc Switching back and forth between functions will not affect the unique configuration of each function However the instrument will forget the con figurations on power down unless they are saved only one instrument configuration can be saved Unique setup conditions can be saved by using SAVE under DMM SETUP or by sending device dependent com mand L1 over the IEEE 488 bus These user saved default conditions will prevail over the factory default conditions on power up or when a DCL or SDC is asserted over the bus IEEE Address and Line Frequency Any IEEE address and line frequency setting can be saved as default conditions by using the SAVE option under DMM SETUP or by sending L1 over the bus See para graph 2 7 for complete information on using DMM SETUP NOTE An UNCAL error will set the IEEE address
253. s gt 200Hz MAXIMUM VOLTAGE BURDEN RESPONSE True root mean square ac coupled CREST FACTOR ratio of peak to rms Up to 3 1 allowable at 25 full range NON SINUSOIDAL INPUTS Specified accuracy for fundamental frequencies lt 1kHz MAXIMUM ALLOWABLE INPUT 3A Protected with 3A 250V fuse accessible from front panel SETTLING TIME 1 second to within 0 1 of final reading dB ref 1mA ACCURACY 48 1 Year 18 28 C 20 Hz 10 kHz INPUT 14 to 69 dB 200 to 3 A RESOLUTION _ 0 01 dB 0 6 DCV DCA ACV ACA Continuous External Trigger Triggered Via Into Memory Into Memory 488 Bus RESO MUX MUX LUTION OFF ON OFF ON OFF ON 4 2 Digit 65 65 150 62 80 49 5 Digit 35 29 9 7 5 40 33 9075 34 29 9 7 5 OHMS are for 50Hz operation shot on TALK 488 BUS IMPLEMENTATION MULTILINE COMMANDS DCL LLO SDC GET UNT UNL SPE SPD UNILINE COMMANDS IFC REN SRQ INTERFACE FUNCTIONS 581 1 6 L4 LEO SR1 DTI E1 All front panel functions and programs are available over the IEEE 488 bus in addition to Status Service Request Out put Format EOI Trigger Terminator Display Message and Non Volatile TRANSLATOR IEEE 488 address is programmable from the front panel MODEL 1992 SCANNER OPTION CONTACT CONFIG
254. s Data Transmission Times Lists typical times when accessing instrument data over the bus 3 12 Scanner Programming Discusses programming commands used with the optional Model 1992 Scanner 3 2 A SHORT CUT TO IEEE 488 OPERATION The paragraphs below will take you through a step by step procedure to get your Model 199 on the bus as quickly as possible and program basic operating modes Refer to the remainder of Section 3 for detailed information on IEEE 488 operation and programming Step 1 Connect Your Model 199 to the Controller With power off connect the Model 199 to the IEEE 488 in terface of the controller using a standard interface cable Some controllers include an integral cable while others require a separate cable Paragraph 3 3 discusses bus con nections in more detail Step 2 Select the Primary Address Much like your home address the primary address is a way for the controller to refer to each device on the bus individually Consequently the primary address of your Model 199 and any other devices on the bus for that mat ter must be the same as the primary address specified in the controller s programming language or you will not be able to program instrument operating modes and ob tain data over the bus Keep in mind that each device on _ the bus must have a different primary address 3 1 IEEE 488 PROGRAMMING The primary address of your Model 199 is set to 26 at the factory but you can p
255. s require only two cal points 1 Place the unit in the CAL UNLOCK state to enable calibration The switch is accessed from the front panel of the instrument through the access hole 2 Select the function and range to be calibrated DC VOLTS AC VOLTS OHMS DC AMPS or AC AMPS 535 digit resolution zero off and filter off 3 Select the front panel calibration program as follows A Press SHIFT LOCAL The following message will be displayed briefly CAL B The default calibration point which is a high end reading for the selected range and function will now be displayed For example if the 3V DC range was selected in step 2 the following calibration point will be displayed 3 00000 VDC 6 3 MAINTENANCE 4 If a different calibration point is to be used enter the new value using the data buttons 0 through 9 Each press of a data button displays the number at the cur sor location identified by the bright flashing digit and moves the cursor to the next digit If the cursor is mov ed past the least significant digit it will move back to the most significant digit displayed for several seconds WORKING 7 For DCV ranges only the plus full range value will be displayed 3 00000 VDC 8 Key in the calibration value if different connect the calibration signal Press NEXT 9 The low end calibration point will now be displayed For the 3VDC range the following calibration point wil
256. screws must be installed to ensure proper grounding The analog board shield must not be removed 9 Connect one end of the supplied two conductor ca ble to J30 on the scanner card and the other end to 129 on the digital board 10 Move Jumper W2 to position B as shown in the illus tration 11 Using a pair of diagonal cutters cut jumper W3 on the digital board see Figure 6 13 for location This step is necessary to enable scanner card operation 12 Replace the case cover and bezel and secure them with the screws removed earlier Proceed to the fol lowing paragraph to check out the scanner card to verify that it is operational 6 8 2 Card Checkout Use the procedure below to test the functionality of the Model 1992 after installation 1 Connect a short jumper wire between the H and L ter minals of each channel input on the two terminal blocks 2 Connect the A and B outputs together H to H Lio L and then connect the outputs to the VOLTS OHMS and LO terminals on the rear panel to HI L to LO Use the supplied output cables Ut e 10 11 Press SHIFT SCAN SETUP then NEXT twice to 19 20 Plug the connecting blocks into the scanner card and make sure the front panel INPUT switch is in the rear position Plug n the Model 199 and turn on the power Press the SCANNER button and verify that the follow ing message is displayed CHANNEL I instead
257. scribe Be sure to include your name and phone number on this service form
258. supplied lethal voltages may be present on the scanner card terminals CAUTION Maximum scanner signal level is 200V 100mA any terminal to earth ground is 350V peak Ex ceeding these values may damage the scanner card Using the Supplied Output Cables Red and black output cables with banana plugs are sup plied with the scanner for convenient connections to the rear panel input jacks Prepare and connect these cables as follows 1 Strip the ends of the cables 5 16 then twist the strands together 2 Connect the red cables to OUT A HI and OUT B HI Tighten screws securely 3 Connect the black cables to OUT A LO and OUT B LO Tighten screws securely 4 For 2 pole connections plug the two red cables and two black cables together and then plug them into the rear panel VOLTS OHMS Hi red and LO black jacks Figure 2 5 For 4 pole connections plug the cables in as shown in Figure 2 11B 2 pole Connections Two pole connections are used for volts and 2 wire resistance measurements In order to use the 2 pole mode the OUT A and OUT B terminals must be connected together H to H L to L and to the DMM In the 2 pole mode if only OUT A is connected to the DMM input on ly channels 1 4 will be routed through the relays Similar ly channels 5 8 will be available if only OUT B is connected For volts and 2 wire resistance measurements connect the outputs to the VOLTS OHMS terminals H to HI L to LO
259. surements 2 6 5 Low Level Measurement Considerations Accuracy Considerations For sensitive measurements other external considerations besides the Model 199 will affect the accuracy Effects not noticeable when working 2 10 with higher voltages are significant in microvolt signals The Model 199 reads only the signal received at its input therefore it is important that this signal be properly transmitted from the source The following paragraphs in dicate factors which affect accuracy including thermal emfs and stray pick up __ Shielding AC voltages which are extremely large com pared with the DC signal may erroneously produce a DC output Therefore if there is AC interference the circuit should be shielded with the shield connected to the Model 199 input LO particularly for low level sources Improper shielding can cause the Model 199 to behave in one or more of the following ways 1 Unexpected offset voltages 2 Inconsistent readings between ranges 3 Sudden shifts in reading To minimize pick up keep the voltage source and the Mode 199 away from strong AC magnetic sources The voltage induced due to magnetic flux is proportional to the area of the loop formed by the input leads Therefore minimize the loop area of the input leads and connect each Signal at only one point Thermal EMFs Thermal emfs thermoelectric potentials are generated by thermal differences between the junct
260. t 10 When the unit returns to normal display press SHIFT STORE Key in the desired number of readings to store When storing data the number of readings is equal to the number of channels per scan times the number of scan sequences desired For example if you desire to scan all eight channels with a total of 10 scan se quences the data store size would be 80 11 Press NEXT once the desired data store size has been selected The STO indicator will flash on to show the unit is waiting for trigger Scanning will also cease at this point 12 Press TRIGGER or apply an external trigger pulse to initiate scanning at cahnnel 1 and storage For the STEP mode one channel interval will be scanned and stored while in the SCAN mode one set of channels per trigger will be scanned and stored 13 Press any function button to cancel data store Scan ning can be cancelled by programming a channel limit of 0 14 Data be recalled during or after storage as dis cussed below RCL will flash when all locations are full except in wrap around mode One Shot Trigger Data Store Scanning Use the procedure below to trigger scanned data into data store In the STEP mode one channel per trigger will be scanned and stored while in the SCAN mode one set of channels per trigger will be scanned and stored 1 Select the range and function as required 2 Use TRIG SETUP to program the one shot trigger mode 3 Using SCAN SET
261. t the instrument will display the ratio of channel 2 to channel 1 in other words the gain of amplifier A1 To display the gains of the remaining amplifiers press TRIGGER and note the displayed ratio for each channel If data store was enabled in step 9 press SHIFT RECALL to review the gain data Selecta location of 1 then press NEXT to view the data which will be the absolute input voltage value Press uprange to review channel 2 through 8 data which will show the gain values of the respective amplifiers Amplifier Frequency Response The test configuration discussed above can be modified somewhat to determine the bandwidth of eight amplifiers connected to the channel inputs The equipment con figuration for this test is shown in Figure 2 16 This test setup is similar to that shown in Figure 2 15 To determine bandwidth we can use the commonly used points in frequency response The dB function of the Model 199 simplifies this task a great deal To Channel Input L Terminals 1992 CARD Figure 2 16 Amplifier Frequency Response Test Configuration 2 36 BASIC DMM OPERATION The basic test procedure is as follows 1 Press SHIFT TRIG SETUP and program the unit for the one shot trigger mode 2 Using SCAN SETUP select the 2 pole STEP scan and ratio off modes 3 Select the ACV function then select a range large enough for the expected amplifier output voltages 4 Program a chan
262. t 5 digit resolution is 606 000 counts With zero disabled the displayed reading range of the instrument is 303 000 counts With zero enabled the Model 199 has the capability to display 606 000 counts This increased display range ensures that the dynamic measurement range of the instrument is not reduced when using a zero BASIC DMM OPERATION baseline value The following two examples will use the maximum allowable zero values 303 000 counts and 303 000 counts to show that dynamic measurement range will not be reduced It is important to note that the increased display range does not increase the maximum allowable input level to the instrument For example on the 3V range the Model 199 will always overrange when more than 3 03V is connected to the input Example 1 The instrument is set to the 3V DC range and a maximum 3 03000V is established as the zero value When 3 03000V is connected to the input of the Model 199 the display will read 0 00000V When 3 03000 is con nected to the input the display will read 6 06000V Thus the dynamic measurement range of the Model 199 is 0V to 6 06V which is 606 000 counts Example 2 The instrument is still set to the 3V DC range but a maximum 3 03000V is the zero level When 3 03000V is connected to the input of the Model 199 the display will read 0 00000V When 3 03000V is connected to the input the display will read 6 06000V Thus the dynamic measurement r
263. t be longer than the delay to avoid the INTERVAL OVERRUN error 2 11 5 Using Filtering with the Scanner The Model 199 uses the running average type of filtering When the front panel filter is on FLTR on additional averaging is used as discussed in paragraph 2 6 3 For that reason the reading rates are slower when the front panel filter is enabled For normal non scanner operation the display still up dates while the filtering process is still going on Under these conditions the FLTR light blinks until the final filtered reading is being displayed With scanner opera tion however the unit will not advance to the next chan nel until the final filtered reading has been taken Thus the maximum scan rates available will be slower with the filter on than with it turned off 2 38 The instrument will advise you if you have exceeded the maximum scan rates In the continuous trigger mode the INTERVAL OVERRUN message will be displayed if the programmed interval is too short for the present instru ment configuration In teh one shot trigger mode the unit will display the TRIGGER OVERRUN message if it is still processing a reading when triggered 2 11 16 Minimum Scan Interval Times As discussed previously the minimum usable interval depends on the function range resolution as well as the multiplexer and filter states Table 2 7 summarizes typical minimum interval times for various ranges a
264. t in instrument damage 2 2 2 Power Up Sequence The instrument can be turned on by pressing in the front panel POWER switch The switch will be at the inner most position when the instrument is turned on Upon power up the instrument will do a number of tests on itself Tests are performed on memory ROM RAM and E PROM If RAM or ROM fails the instrument will lock up If EPROM FAILS the message UNCAL will be displayed See para graph 67 2 for a complete description of the power up self test and recommendations to resolve failures Immediately upon power up the unit will display the pro grammed line frequency For example FREQ 60HZ 2 2 3 Default Conditions Default conditions can be defined as setup conditions that the instrument will return to when a particular feature or command is asserted The Model 199 will return to either factory default conditions or user saved default conditions Factory Default Conditions At the factory the Model 199 is set up so that the instru ment is configured to certain setup conditions on the initial power up These factory default conditions are listed in Tables 2 1 and 37 located in Section 3 If alternate setup conditions are saved see User Saved Default Conditions the instrument can be returned to the factory default con ditions by using Reset available under DMM SETUP See paragraph 2 7 BASIC OPERATION Table 2 1 Factory Default Condition
265. t some may not Programming Example Enter the following program in to the computer to define a Translator word SETUP1 to emulate the command string FIROX REMOTE 25 OUTPUT 5 ALIAS SETUP1F1RBXE OUTPUT 726 SETUP The Translator word will be defined to emulate the Keithley command string The instrument will go to the ACV func tion F1 and enable autorange RO IEEE 488 PROGRAMMING Table 3 14 Translator Error Messages TRANSERR14 TRANSERRI5 Translator word exceeds 31 characters 16 TRANSERRIZ Use of an X in a Translator word error string Use of a in a Translator word Sending the character Use of LIST in a Translator definition TRANSERR18 19 TRANSERR20 21 TRANSERR23 Use of SAVE in a Translator definition 3 10 2 Wild Card An advanced feature of Translator software is its wild card capabilities By using the reserved character the same basic Translator word can be used to select all options of a command With this feature a DDC option number is sent with the wild card Translator word The format for using the wild card is shown in the following example which defines the word FUNCTION as a substitute for the F command ALIAS FUNCTION F X FUNCTION 1 FUNCTION 2 The first statement defines FUNCTION as the wild card Translator word for the F command The wild card
266. tablished as the power up default conditions Translator Software User defined words stored in non volatile memory can be used to replace standard com mand strings over the IEEE 488 bus Optional Fieid Installable Internal Scanner Allows the unit to switch up to 8 2 pole channels or 4 4 pole channels 1 3 WARRANTY INFORMATION Warranty information may be found on the inside front cover of this manual Should it become necessary to exer cise the warranty contact your Keithley representative or the factory to determine the proper course of action Keithley Instruments maintains service facilities in the United States United Kingdom and throughout Europe Information concerning the application operation or ser vice of your instrument may be directed to the applications engineer at any of these locations Check the inside front cover for addresses 1 4 MANUAL ADDENDA Information concerning improvements or changes to the instrument which occur after the printing of this manual will be found on an addendum sheet included with the manual Be sure to review these changes before attempt ing to operate or service the instrument 1 5 SAFETY SYMBOLS AND TERMS The following safety symbols and terms are used in this manual or found on the Model 199 The symbol on the instrument denotes that the user should refer to the operating instructions in this manual The M on the instrument denotes that a hazardous pot
267. te This sequence is used tc transfer data talk and listen addresses as well as multiline commands SOURCE DATA SOURCE VALID NRFD H E ACCEPTOR ACCEPTOR DATA DATA TRANSFER TRANSFER BEGINS ENDS Figure C 2 IEEE Handshake Sequence APPENDIX C BUS COMMANDS Commands associated with the IEEE 488 bus can be grouped into the following three general categories Refer to Table C 1 Uniline Commands These commands are asserted by set ting the associated bus line true For example to assert REN Remote Enable the REN line would be set low true Multiline Commands General bus commands which are sent over the data lines with the ATN line true Device dependent Commands Commands whose mean ings depend on the device in question These commands are transmitted via the data lines while ATN is false Table C 1 IEEE 488 Bus Command Summary Uniline REN Remote Enable EOI IFC Interface Clear ATN Attention SRQ Multiline Universal LLO Local Lockout DCL Device Clear SPE Serial Enable SPD Serial Poll Disable SDC Selective Device Clear GTL Go To Local GET Group Execute Trigger UNL Unlisten UNT Untalk Addressed Unaddressed Device dependent Care Sets up devices for remote operation Marks end of transmission Clears Interface Defines data bus contents Controlled by external device
268. ted by a device on the bus when it requires service from the controller Universal Multiline Commands Universal multiline commands are those commands that required no addressing as part of the command sequence devices equipped to implement these commands will do so simultaneously when the commands are transmit ted As with all multiline commands these commands are transmitted with ATN true ms LLO Local Lockout LLO is sent to instruments to lock out front panel or local operation of the instrument DCL Device Clear DCL is used to return instruments to some default state Usually devices return to their power up conditions SPE Serial Poll Enable SPE is the first step in the serial polling sequence which is used to determine which device on the bus is requesting service C 4 SPD Serial Poll Disable SPD is used by the controller to remove all devices on the bus from the serial poll mode and is generally the last command in the serial polling sequence Addressed Multiline Commands Addressed multiline commands are those commands that must be preceded by an appropriate listen address before the instrument will respond to the command in question Note that only the addressed device will respond to the command Both the command and the address preceding it are sent with ATN true SDC Selective Device Clear The SDC command per forms essentially the same function as DCL except that on th
269. th a minimum number of bus lines In keeping with this goal the bus has eight data lines that are used both for data and many commands Additionally the bus has five manage ment lines which are used to control bus operation and three handshake lines that are used to control the data byte transfer sequence A typical configuration for controlled bus operation is shown in Figure 0 1 A typical system will have one con troller and one or more devices to which commands are given and in most cases from which data is received Generally there are three categories that describe device operation controller talker and listener The controller does what its name implies it controls other devices on the bus A talker sends data usually to the con troller and a listener receives data Depending on the in strument a particular device may be a talker only a listener only or both a talker and a listener The Model 199 has both talker and listener capabilities There are two categories of controllers system controller and basic controller Both are able to control other devices but only the system controller has absolute authority in the system In a system with more than one controller only one controller may be active at any given time Certain command protocol allows control to be passed from one controller to another The bus is limited to 15 devices including the controller Thus any number of devices may be present on the bus
270. the Model 199 receives the SDC command it will return to the default conditions see paragraph 3 9 11 Table 3 7 lists factory default conditions To transmit the SDC command the controller must per form the following steps 1 Set ATN true 2 Address the Model 199 to listen 3 Place the SDC command byte on the data bus Notes 1 SDC will return the instrument to the default line fre quency setting 22 SDC will not have any effect on the current IEEE address Programming Example Using several front panel con trols alter instrument states from the default configura tion Send SDC with the following statement CLEAR 726 When the above statement is executed the instrument returns to the default configuration 3 8 7 GET Group Execute Trigger GET may be used to initiate a Model 199 measurement se quence if the instrument is placed in the appropriate trig ger mode see paragraph 3 9 Once triggered the instru ment will take a single reading or series of readings To send GET the controller must perform the following sequence 1 Set ATN low 2 Address the Model 199 to listen 3 Place the GET command byte on the data bus Programming Example Type in the following statements to place the instrument in the correct trigger mode for pur poses of this demonstration REMOTE 726 OUTPUT 726 ETENI Now trigger the reading by sending GET with the follow ing statement TRIGGER 226 The rea
271. the data store is full 4 When the data store is full 5 If a trigger overrun error occurs 3 22 Upon power up or after a DCL or SDC command is re ceived SRQ is disabled SRQ Mask The Model 199 uses an internal mask to deter mine which conditions will cause an 5 to be generated Figure 3 7 shows the general format of this mask can be programmed by sending the ASCH letter M followed by a decimal number to set the appropriate bit the SRQ mask Decimal values for the various bits are summarized in Table 3 11 Note that the instrument may be programmed for more than one set of conditions simultaneously To do so simply add up the decimal bit values for the required SRQ conditions For example to enable SRO under reading overflow and buffer full con ditions send M3X To disable SRQ send MOX This com mand will clear all bits in the SRO mask Serial Poll Byte Format The serial poll byte contains in formation relating to data and error conditions within the instrument The general format of the serial poll byte which is obtained by using the serial polling sequence as described in paragraph 3 8 8 is shown in Figure 37 IEEE 488 PROGRAMMING stion 87 B2 Bo Position B7 85 B4 Bt Value o forfor lor fon or nn righting 128 64 4 2 v Weighting 128 32116 412 1 1 SRQ 199 Status Byte only 1 Error 45 Ready 1
272. the unit displays the NO SCANNER message you may have forgotten to cut jumper W3 as described in paragraph 6 8 1 Press 0 to return to normal display Select the following Model 199 operating modes Function OHMS Range 3000 Resolution 5 digits Filter off Zero off Temporarily short the rear panel VOLTS OHMS ter minals then press ZERO Leave zero enabled for the remainder of the checkout procedure Press SHIFT TRIG SETUP and use uprange or downrange so that the ONE SHOT trigger mode message is displayed Press NEXT twice to return to normal display display the present scan mode Use uprange or downrange to display the following STEP Press NEXT to complete programming 14 Press SCANNER and note that the instrument displays the following LIMIT Press 8 to program the limit 16 Press TRIGGER to close channel 1 The instrument will display the resistance reading on channel 1 Verify the resistance reading is less than 10 Press TRIGGER to cycle to the next channel Verify that the resistance reading is less than 12 Repeat step 18 for the remaining channels If all channels show an overflow reading in its test it is probable that the card was installed improperly refer to paragraph 6 8 1 If only one channel measures im properly check to see that the channel jumper is in stalled properly 6 23 21 Turn off the instrument power and un
273. tible trigger pulses to take one or more readings depen ding on the selected trigger mode See paragraph 2 9 for additional information VOLTMETER COMPLETE OUTPUT This BNC output connector provides a TTL compatible negative going pulse when the Model 199 has com pleted a reading It can be used to trigger other in struments as discussed in paragraph 2 9 2 4 2 Line Voltage Aspects 4 Line Voltage Selection Switch This switch selects the operating line voltage of the instrament Before operation be sure the switch is in the correct posi tion for the line voltage in your area LINE FUSE The line fuse provides protection for the AC power line input Refer to paragraph 6 3 for fuse replacement procedures 6 LINE VOLTAGE receptacle Power is applied to the instrument through the supplied power cord to the three terminal grounded AC receptacle Note that the selected supply voltage is marked on the rear panel below the receptacle 2 4 3 IEEE 488 Connector 7 The IEEE 488 connector is used to interface the Model 199 to the IEEE 488 bus IEEE 488 interface functions are marked immediately above the connector Refer to Section 3 for detailed IEEE 488 information 2 6 2 4 4 Scanner Card Slot 5 The optional Model 1992 Scanner Card installs in this slot Refer to paragraphs 2 11 and 3 12 for scanner operation and programming information Section 6 contains scanner in stallation procedures 2 5 DISPLAY ME
274. tiplex enabled period in milliseconds 0msec to 999999msec 3 9 18 Cr ume ae eee Hit Button Hn front panel button number n Display Display up to 10 character message a character 3 9 21 Cancel display mode 55555 3 15 488 PROGRAMMING NOTES 1 REN must be true when sending device dependent com mands to the instrument or it will ignore the command and display a bus error message 2 Scanner programming commands are covered in paragraph 3 12 General Programming Example Device dependent com mands may be sent from the computer with the follow ing statement t AS in this case contains the ASCII characters representing the command string 3 9 1 Execute X The execute command is implemented by sending an ASCII over the bus Its purpose 15 to direct the Model 199 to execute other device dependent commands such as F function or R range Usually the execute character is the last byte in the command string a number of com mands may be grouped together into one string however there may be certain circumstances where it is desirable to send a command string at one time and then send the execute character later on Command strings sent without the execute character will be stored within an internal com mand buffer for later execution When the X character is finally transmitted the stored commands will be executed a
275. triggering trigger mode selection as well as trigger delay and reading interval programming 2 8 1 Trigger Mode Selection The Model 199 may be operated in two basic trigger modes one shot and continuous In the one shot mode a separate trigger is required to initiate each reading For the con tinuous mode however only a single trigger is required with the conversion rate determined by the programmed reading interval The continuous trigger mode is the fac tory default To check or change the selected trigger mode proceed as follows 1 Press SHIFT TRIG SETUP The instrument will display the presently selected trigger mode For the continuous mode the display will show CONTINUOUS 2 For the one shot mode the display reads ONE SHOT 3 To toggle the trigger mode press uprange or downrange 4 Once the desired trigger mode is displayed press NEXT to scroll to the next menu selection trigger delay or press NEXT to return to normal front panel display 2 19 BASIC DMM OPERATION 2 8 2 Trigger Sources For standard bench operation there are two trigger sources available front panel TRIGGER button and the EXTER NAL TRIGGER INPUT jack Upon power up both these trigger sources will be enabled Additional triggers include TEEE 488 X GET and talk commands as discussed in paragraph 3 97 NOTES 1 TRIGGER is always enabled regardless of the selected trigger souxce however all front panel buttons
276. ty Device Clear capability Device Trigger capability No Controller capability Open Collector Bus Drivers No Extended Talker capabilities No Extended Listener capabilities 3 5 PRIMARY ADDRESS SELECTION The Model 199 must receive a listen command before it will respond to addressed commands over the bus Similarly the instrument must receive a talk command before it will transmit its data These listen and talk com mands are derived from the primary address of the instru ment which is set to 26 at the factory Until you become more familiar with your instrument it is recommended that you leave the address at this value because the pro gramming examples in this manual assume the instrument is programmed for that address The primary address can be programmed for any value between 0 and 30 However each device on the bus must have a unique primary address a factor that should be _kept in mind when setting the primary address of the Mode 199 Most controllers also use a primary address consult the controller instruction manual for details Whatever address is used it must be the same as the value specified as part of the controller s programming language To check the presently programmed primary address or to change to a new one proceed as follows 1 Press SHIFT DMM SETUP then NEXT The current primary address will be displayed For example if the current address is 26 the following messa
277. ty do not touch the test leads or the instrument while power is applied to the circuit under test Turn the power off and discharge all capacitors before connecting or disconnecting the instrument Always disconnect all unused test leads from the instrument Do not touch any object which could provide a current path to the common side of the circuit under test or power line earth ground Always make measurements with dry hands while standing on a dry in sulated surface capable of withstanding the voltage being measured Exercise extreme safety when testing high energy power circuits AC line or mains etc Refer to the High Energy Circuit Safety Precautions found in paragraph 2 6 Basic Measurements Do not exceed the instrument s maximum allowable input as defined in the specifications and operation section SPECIFICATIONS ACCURACY rdg counts INPUT RESO RESIS 24 Hour 90 Days 1 Year RANGE ELUTION TANCE 23 1 189 28 C 18 28 C 300 mV gt 1 0 0 004 3 0 009 33 0 012 32 3 v 10 V gt 160 0 00342 0 00642 0 007 2 30 11 0 000442 0 0080 2 00042 30 V 1 mV 0 004 2 0 008 2 0 09 2 4 digit accuracy count error is 5 except 15 on 300mV range Relative to calibration standards When properly zeroed gt 120dB at dc 50Hz or 60Hz 40 05 with 1kQ in either lead NMRR gt 604 at 50Hz 60Hz 10 0596 MAXIMUM ALLOWABLE
278. un error enter the following statements into the com puter keyboard REMOTE 726 726 Tox OUTPUT 725 ff ETT Note that the trigger overrun message is displayed after the third statement is executed Big String Error A big occurs when nee display a message using the D command that exceeds 10 characters Blank display digits used in the message count as characters The invalid message is ignored and the following message is displayed briefly when a big string error occurs BIG STRING Pro ing Example Enter the following statements in to the computer to demonstrate a big string error REMOTE ree OUTPUT 726 DHBWEARERYOUTS The big string error will occur because the message is made 12 characters Cal Locked Error A cal locked error occurs when trying to calibrate the in strument over the bus with the front panel calibration switch in the disable position Calibration commands will be ignored and the following message will be displayed brietly z i CAL LOCKED Interval Overrun Error A interval overrun error occurs when the instrument can not store readings in the data store or scan at the pro grammed interval Q command However the instrument will continue to store readings as fast as it can run The following message is displayed briefly when a short time error Occurs INTERVAL OVERRUN Programming Example To demonstrate an interval over run error
279. unction Do not zero this level out Paragraph 2 6 10 provides an of ARE offset 4 Connect the signal to be measured to the selected in put terminals as shown in Figure 2 6 5 Take the reading from the display Clarifications of TRMS ACV Specifications Maximum Allowable Input The following graph sum marizes the maximum input based on the 107 2 specification Maximum Input TRMS AC Volts Maximum Input TRMS AC Volts 2 5 gt lt o Frequency Hz Settling Time Isec to within 0 1 of change in reading This time specification does not include A D conversion time AC Voltage Source MODEL 199 Caution Maximum Input 300V RMS 425V Peak 107 V Hz Input impedance 1 0 Shunted by lt 100pF Figure 2 6 TRMS AC Voltage Measurement 2 6 8 Current Measurements DC or TRMS AC The Model 199 can make DC or TRMS AC current measurements from 100nA at 5 24 resolution to Use the following procedure to make current measurements 1 Select the DC current or AC current function by pressing the AMPS button also press AC for AC current 2 Select a range consistent with the expected current or use autorange 3 Connect the signal to be measured to the front panel input terminals as shown in Figure 27 4 Take the reading from the display Current Source MODEL 199 Front Pane only Caution Maximum Continuous Input Figure 2 7 Current Measur
280. urce Voltage and current measurements are based on compar ing the unknown signal with an internal 2 8V reference voltage source During each measurement cycle the unknown signal is sampled and then compared with signal common and the 2 8V reference values VR2 provides highly stable 64V reference while U13 and R66 provide a constant current to minimize zener voltage variations R68 and R69 divide down the 64V value to the final 2 8V reference voltage 5 3 4 Input Buffer Amplifier The input buffer amplifier U46 provides isolation between the input signal and the A D converter The amplifier can be configured for X1 or X10 gain with R71 and R64 acting as the feedback network When X1 gain is selected by the microprocessor feedback is routed through pin 12 of the analog switch U45A At X10 gain feedback is routed through pin 13 of the multiplex switch Amplifier gain con figurations for the various functions and ranges are listed in Table 5 1 Table 5 1 Input Buffer Amplifier U46 Gain Configuration Function Range Gain DC Volts 300mV 3 300V AC Volts All 3000 3k 300MQ DC Amps All AC Amps All Ohms 5 8 5 4 A D CONVERTER The Model 199 uses a constant frequency variable pulse width analog to digital converter simplified schematic _ of the A D used in the Model 199 is shown in Figure 5 6 The charge balance phase begins when the input enable disable line is set high This oc
281. ure 6 6 3 For front panel calibration press SHIFT LOCAL and proceed as follows A With the 300 000mV AC calibration point displayed on the Model 199 set the AC calibrator to output 300 000mV at 50082 B After allowing sufficient time for the calibrator voltage to settle press the NEXT button The follow ing message will be displayed for several seconds WORKING C With the 030 000mV AC calibration point displayed set the AC calibrator to output 30 000mV at 500Hz Resistan 199 Calibration Calibrator IEEE 488 199 Range Set Up Point Setting Bus Commands 300 Q Figure 6 3 190000 Q 000000 9 Figure 6 3 1 90000 0 00000 Figure 6 3 19 0000 00 0000 Figure 6 4 190 000 000 000 Figure 6 4 1 90000MQ 0 00000MQ Figure 6 4 19 0000M2 00 0000MQ Figure 6 4 100 00MQ 000 00MQ Short 00 VOXCIX 1 9kQ V1 9E3XCOX Short 00 VOXCIX VJ9ESXCOX VOXCIX 190 Short 02 VOXCIX 1 9MQ 1 9 6 Short 00 VOXCIX 19 0 VI9E6XCOX Short 00 VOXCIX 100M2 100 6 Short 00 VOXC1X D After allowing the calibrator voltage to settle press the NEXT button The following message will be displayed for several seconds WORKING E The instrument will exit the calibration program and return to the 300mV AC range E Repeat the procedures in step 3 for the remaining ACV ranges using Table 6 7 as a guide For IEEE 48
282. urge all Translator words from tem porary memory REMOTE ras QUTPUT 726 FORGETS 3 11 BUS DATA TRANSMISSION TIMES A primary consideration is the length of time it takes to obtain a reading once the instrument is triggered to make a conversion The length of time will vary somewhat de pending on the selected function and trigger mode Table 3 15 gives typical times 3 12 SCANNER PROGRAMMING The paragraphs below discuss the programming com mands necessary to control the optional Model 1992 2 4 Pole Scanner The Model 1992 allows you to individually switch or scan up to eight 2 pole channels or four 4 pole channels Commands to control the scanner are summarized in Table 3 16 For detailed information on scanner connections refer to paragraph 2 11 3 35 EEE 488 PROGRAMMING 300 3k 30k 300 8msec Bmsec 8msec 8msec 77msec 7 9msec 7 9msec 79msec _ 14 9msec 30 1msec 21 9msec 21 9msec Table 3 15 Typical Trigger to First Byte Out Times 15 9msec 15 9msec 15 9msec 15 9msec 15 1msec 15 1msec 14 9msec 25msec 278msec 25msec 278msec 25msec 27 8msec 25msec 28 msec 24 Imsec 28msec 25 msec 28msec 25 msec 28msec 25 msec 28msec 25 3msec 27 1msec 24 9msec 26 9msec 25 1msec 28 1msec 103msec 113msec 107msec 119msec 106msec 119msec 108msec 122msec 30 9msec 34 29 9msec 34 1msec 31 1msec 34 1msec 30 9msec 34 1msec
283. verified as explained in paragraph 6 4 10 step 5 Calibration can be performed from the front panel or over the 488 bus NOTE A CONFLICT error will be displayed and the CONFLICT error bit in the U1 status word will be set when trying to calibrate the instrument while it is in an improper state i e dB Also if an UNCAL error occurs be sure to check the line frequency setting before performing calibration 6 4 1 Recommended Calibration Equipment Table 6 4 lists recommended calibration equipment Alter nate equipment may be used as long as equipment ac curacy is at least as good as the specifications listed in the table MAINTENANCE Table 6 4 Recommended Calibration Equipment Mfg Description Specifications DC Voltage Calibrator AC Voltage Calibrator AC Power Amplifier Resistance Calibrator 300mV 30V 300V ranges 15 300mV 3V 30V ranges 20Hz 0 1 50Hz 20kHz 0 02 100kHz 0 33 300V range 20Hz 40 1296 5082 20 2 10 0496 100kHz 0 1 3000 ranges 15ppm 30M9 32ppm 300M9 225ppm Current Calibrator 6 4 2 Environmental Conditions Calibration should be performed under laboratory condi tions having an ambient temperature of 23 C 1 C and a relative humidity of less than 70 6 4 3 Warm Up Period Turn on the instrument power and allow it to warm up for at least two hours before beginning the calibration pro cedure If th
284. will be locked out when the unit is in remote 2 Triggering the unit while it is still processing a reading from a previous trigger will generate the TRIGGER OVERRUN message 2 8 3 Trigger Delay The trigger delay period is the time from the trigger point until the unit takes a reading This delay period is also used after each channel closure when using the scanner For the continuous mode the delay period affects only the first conversion however with the one shot mode the delay period affects every conversion with the instrument waiting the programmed delay time after each trigger before taking a reading For example if you program a between individual readings when the instrument is in the continuous trigger mode Interval also affects the rate of data store operation as discussed in paragraph 2 10 as well as the interval between channels step mode or scan se quences scan mode when using the optional Model 1992 Scanner see paragraph 2 11 The unit can be programmed for either default or selected interval operation With default interval SELECT OFF a preset interval of 175msec is automatically selected With selected interval SELECT ON a user defined interval can be programmed The allowable range for selected in terval is I5msec to 999 999sec 1msec increments NOTE Programming too short an interval for the present instrument configuration when using the scanner or data store will result in the
285. wing adjustments MAINTENANCE Perform Front Pane or IEEE Calibration Step 3 or 4 MODEL 199 Shielded Cable Power AC Voltage Amplifier Calibrator Model 5215A Model 5200A Check High Frequency 70kHz Step 5 Figure 6 6 TRMS AC Volts Calibration Configuration Adjust Trim Capacitors Step 6 ACV Calibration Complete Figure 6 5 Flowchart of AC Volts Calibration Procedure 6 10 MAINTENANCE WARNING LETHAL VOLTAGES MAY BE PRESENT ON SHIELD WHEN USED WITH FLOATING SOURCES 300VAC RANGE ADJUSTMENT 30VAC RANGE ADJUSTMENT NOTE ADJUSTMENTS ARE ACCESSIBLE THROUGH HOLES IN SCANNER BOARD WHEN UNIT 1550 EQUIPPED Figure 6 7 TRMS AC Volts High Frequency Calibration Adjustments 30V and 300V Ranges MAINTENANCE 6 4 11 DC Current Calibration Perform the following procedure to calibrate DCA NOTE For front panel calibration omit step 4 of the following procedure For IEEE 488 bus calibration omit step 3 1 Select the DC AMPS function and the 30mA range 2 Connect the DC current calibrator to the instrument as shown in Figure 6 8 3 For front panel calibration press SHIFT LOCAL and proceed as follows A With the 30 0000mA DC calibration point displayed on the Model 199 set the current calibrator to out put 30 0000mA B After allowing sufficient time for the measurement to settle press the NEXT button The following message will be displaye
286. y the TRIGGER OVERRUN message if it is still processing a reading from a previous trigger 2 11 10 Using Data Store with the Scanner The data store feature of the Model 199 can be used with the scanner to store data for later recall For short inter vals in the STEP mode and for the SCAN mode using data store is the recommended method of operation because of the rapid scanning rates possible with the Model 199 Scanning at Programmed Intervals 1 Select the range and function as required 2 Press SHIFT TRIG SETUP and program the con tinuous trigger mode 3 Press NEXT twice to advance to the interval selection menu Use uprange or downrange as necessary to select interval then press NEXT 4 With select interval use the data entry keys to program the storage interval in the range of 25msec to 999 999sec Keep in mind that the unit will store one channel per interval in the STEP mode and one set of channels per interval in the SCAN mode 5 Press NEXT to return to normal display after selecting the interval 6 Press SHIFT SCAN SETUP and program the pole mode as required 7 Press NEXT to advance to the scan mode display Use uprange or downrange to select the STEP one chan nel per interval or SCAN one set of channels per in terval mode 8 Press NEXT to program ratio and to return to normal display 9 Press SCANNER and program the desired channel limit Scanning will begin at this poin

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