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Model 4176 - Valhalla Scientific, Inc

1. 34 4 6 1 Configuring the Print Log Function The Print Log function can be set to PRINT LOG or LOG2 Follow these simple steps to configure the function Press the FUNC key followed by the PRINT key PRINT BUTTON MODE 1 PRINT 2 LOG 3 L0G 2 Using the numerical keys from 1 thru 3 select the action that you wish the Print Log function to use and press ENTER The screen will display PRINT MODE SET FOEPRENT STORING NEW SETUP ENTER DATA IN NOVRAM The instrument will automatically return to the previous mode 4 7 View Function The View function allows the user to view how the instrument s functions are configured This function is easy to use and is very useful especially for HLC and TCM users 4 7 1 Using the View function Pressing the VIEW key initiates the View mode Once in this mode the user can select one of the following function keys To exit the View mode press the VIEW key at ay time VIEW KEY OR CLEAR SELECT A FUNCTION UPDATE The screen displays the display update rate and intensity settings SED T DISPLAY RATE ms INTENSITY LEVEL HLC The screen displays the HLC limits for the range that is selected at the time In this mode the user can switch through the ranges to view all the values set as limits weed MIN 11 111mQ MAX 22 222m02 ADDR The screen displays the BAUD rate of the RS 232 interface Also if Option GPIB is installed
2. Syntax ADDRS Example ADDRS sot 1E Response TO lt CELE gt Address number 1 32 Power on default None must be set with ADDRS 10 and SAVESETUP 5 BCD COMMAND Selects BCD mode on or off syntax BCD ON OE OES Example BED ONsEFd BCD lt CELT gt ONSCETES Power on default OFF Note BCD mode on puts the logic level BCD on the rear panel connector and the ranges on the relays outputs See chapter pin o ts and relay descriptions BCD QUERY Responds with BCD mode on or off Syntax BED Example BEDASCE NLE gt ONSCELFES Response SOON OP OR Power on default OFF CALDATE QUERY 7 for BED connector Request the last calibration date and technician initials DVI tax CALDATE Response G0 00 04 VST Power on default 00 00 00 VS CLS COMMAND sets buffers to power on default Syntax EBSCOLELES Ke CNFG COMMAND Turns on and off system configuration items Alarms key beeps other features syntax CNFG lt item number gt lt ON or OFF gt Example CNFG 1 ON lt crlf gt CNEG I Or ES ONS Er Di 1 Supress Alarms 2 Supress Key Beeps Power on defaults OFF CNFG QUERY Responds with CNFG mode on or off Syntax CNEGY Example CNEG ALGE IE ON CTET Response SON Ok OPEN 1 Supress Alarms 2 Supress Key Beeps Power on defaults OFF pleasantly noisy FAULT COMMAND sets an alarm fault to watch the system react syntax FAULT lt Hexadecimal num
3. Select an intensity level using the numerical keys from 1 thru 8 and press ENTER aus SAVING NEW DISPLAY INTENSITY LEVEL STORING NEW SETUP DATA IN NOVRAM The values are stored in memory and the instrument will automatically return to the previous mode 4 5 Run Hold Function The Run Hold function of the 4176 can be configured in three different ways HOLD Pressing the RUN HOLD key will freeze the readings on the display The function window of the screen will flash HOLD To exit the hold state press the RUN HOLD key again PKHI Pressing the Run HOLD key will activate the Peak Hi state The readings on the display will only increment therefore showing the maximum value measured While in Peak Hi state the function window of the screen will flash PKHI To exit this state press the RUN HOLD key again PKLO Pressing the Run HOLD key will activate the Peak Lo state The readings on the display will only decrease therefore showing the minimum value measured While in Peak Lo state the function window of the screen will flash PKLO To exit this state press the RUN HOLD key again 32 4 5 1 Configuring the Run Hold Function The Run Hold function can be set to HOLD PKHI or PKLO Follow these simple steps to configure the function Press the FUNC key followed by the RUN HOLD key EE LEG RUN HOLD ACTION 1 HOLD 2 PKHI 3 PKLO Using the numerical keys from 1 thru 3 select the action that
4. s w o ow 66 RANGE 30 R3 Table 15 RCD Range Truth Table Range A 30 gal 11 me 29 des 10 Range Ranges OFF tal al ig ARE IE OVERLOAD PIN 12 This is a logic 1 when the data on the lines above is an overload indication Note The Data is arbitrary during this condition AVDD amp AGND Pin FUNCTION 14 AVDD 15 AVDD SA AVDD 33 AVDD 34 AVDD 67 Pink FUNCTION Pink FUNCTION la oo AVDD AVDD 16 AGND 17 AGND 18 NC Table 16 BCD Pin Assignment Reference Table 68 Chapter 8 ROUTINE MAINTENANCE 8 1 General This Chapter provides general maintenance information and a procedure for calibrating the ohmmeter The Model 4176 u ohmmeter should be calibrated on a routine basis every 12 months is recommended to ensure continued accuracy Before performing the calibration procedure below the ohmmeter should be allowed to warm up at a stable temperature for at least 30 minutes with the covers in place 8 2 Required Test Equipment The following equipment is required to perform calibration of the 4176 1 Precision resistors with known values within 0 005 the following values will be used 0 0102 0 162 162 100 1000 1kQ and 10kQ 2 DC voltage standard capable of outputting 10mV 300mV and 1V Valhalla Model 2701C is suitable for the task 3 Four wire test lead set 4 Precision Digital Voltmeter Note If this equipment is not available the ohmmeter may b
5. Ga WARNING RISK OF ELECTRICAL SHOCK Frame or chassis ground terminal typically connects to the equipment s metal frame Calls attention to a procedure practice or condition that could cause bodily injury or death Direct current DC The following general safety precautions must be observed during all phases of operation service and repair of this product Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the product Valhalla Scientific assumes no liability for the customer s failure to comply with these requirements Ground the equipment For Safety class 1 equipment equipment having a protective earth terminal an interrupted safety earth ground must be provided from the main power source to the product input wiring terminals or supplied power cable DO NOT operate the product in an explosive atmosphere or in presence of flammable gases or fumes For continued protection replace the line fuse s only with fuse s of the same voltage and current rating and type DO NOT use repaired fuses or short circuited fuse holders Keep away from live circuits Operating personnel must not remove equipment covers or shields Procedures involving the removal of covers or shields are for the use of service trained personnel only Under certain conditions dangerous voltage may exist even with the equipment switch
6. Multi Range Dual 2 Limit Comparator Also used to set and or view the limits used The ADDR key is used to view the setting information for all of the standard or ADDR i 3 optional remote interfaces RUN HOLD The RUN HOLD key is used to switch between run and hold state Also used to 4 select the hold configuration PRINT The PRINT key is used to trigger the output of a print or log package to the RS 5 232 port Also used to select the print log setting TCM The TCM key is used to enable or disable the TCM mode Also used to select 6 temp coefficient and reference and for TC calibration AUTO RNG The AUTO RNG key enables the automatic selection of the range according to the 7 value of the load CAL The CAL key is used to initiate the standard and TCM calibration procedure 8 The BCD key enables the binary coded decimal output on models where the BCD ie oe 9 BCD option is installed The CLEAR key functions like a backspace when entering values The key is also CLEAR none used to return to the previous screen RESET The RESET key resets the ohmmeter returning it to Start Up state none LOCAL The LOCAL key is used to return from a remote to a local state none ENTER The ENTER key is the user confirmation to a display prompt none m k The m k key is used to toggle between polarity symbols where active JE 12 3 2 5 TCM Receptacle and LEDs This portion of the front panel is utilized only during temperature compensated type measurements TC
7. the screen will display the GPIB address ViewAddr will also show if the Option BCD or USB are installed se RS 232 9600 BAUD 36 RUN HOLD The screen will display the configuration of the Run Hold key RUN HOLD RUN HOLD KEY ACTION PKHI PRINT The screen will display the configuration of the Print Log feature PRINT PRINT MODE SET TO PRINT TCM The screen will display the temperature coefficient and temperature reference value set for the TCM mode TCM MEE GEE e 4 A oe ad AE 790 0 de AUTO RNG The screen will display the auto range status on or off and the range that is in use AUG EN AUTO RANGING OFF STATIC RANGE X1 CAL The screen displays the date of the last calibration This is update from the interface CAL LAST CALIBRATION DATE 03 23 04 BCD The screen will indicate if the instrument has Option BCD installed REAR OUTPUT BCD INSTALLED 4 8 SafeMode As a Safety precaution the 4176 is designed with an optional Safe Mode feature With the Safe Mode option activated if an overload persists for more then 10 seconds the 4176 shuts down its current source and displays SAFEMODE on its screen The ohmmeter does not automatically recover from safe mode the user must press the Enter key or any range including Auto to return to measurement mode This is so that the user can be aware that an overload has occurred so that the cause maybe investigated i
8. 2 2 TEMPERATURE COMPENSATOR MODE SPECIFICATIONS ccccsscccssccsscccsccessceesccusccecceusccesseeeesens 8 2 3 GENERAL PEEIEIG TON cuarta ee GO Ee EE EDE GE GE Ge Ee 9 2 4 ENVIRONMENTAL AND POWER REQUIREMENTS aaa aaa aaa aaa see sees see see see ee ee ee se ee ee ee ee ee ee ee ee ee ee ee ee 9 2 9 NO PETE CA TONS ee ND De ee GEGEE EE EE GEE GE ERG OE ee Ee De 9 CHAPTERS GETTING STARTED isi seks eds ese o 10 3 1 NT DUC TON oe DE ER Ge DE Ge Ee EE AE OG EE a ak ee 10 32 ERONTLANEL ne oe RE RE EE EE A 10 3 2 1 TOW CP E EIE 10 A EE RE EE N EE EE AE RO T II I2 KONGE S E EDER ONA EA AE oo EE II Jaa Fumon on NAME CALAIS ica 12 329 LCM Kecopiacie and dl NS 13 A E N AE EA E Tete SEE ERE 14 io LO Rente ED Re eS One Tene Ne Ee TN 14 E rs ES EEEE E 14 3 3 REAR PAN Er E OEE E ee Re Ge Ee OG ee Ge eee oe ee ee eed 15 TT acters od EE N ek AE eo ee EE oe EE ee 15 Era di NE EE EO OE N es 16 Dee DOME COMO OO N OT OR OE N OE N OE OT N IE 16 S AA TA ME AE hea EE II 16 Ee Aoa CC OF e IE RO EO EE RE ONE EN ER 17 3 4 PPTs VG POW ER ON RE N OR OE NT OR EN 18 3 4 1 Power On Default Settings anion eased ewer anatase eee 18 3 5 CONNECTING A LOAD TO THE 41 7 Da aaa aaa aaa aaa nana nen n anen e eene arena reres eres eneeeene sere eeeee vere sene sene se veme vemesenese 19 3 6 NO SELECCION E E HEEP 21 3 7 OVERLOADAND SAFE MODE AR RE EO acera 21 CHAPTER4 MEASUREMENTS MODES AND FUNCTIONS ccccccsssccsscsccscsccsccsccscsceeees 22 4 1 STANDARD ME
9. A anc ayaa 40 S22 Opnon R Rack Mot AGAPO ic Ee IA A AAA A 40 5 3 dis Ma Bi de Soo OE AE AE EE AE OE 41 IS Ar CPT PEL Taa S fonin oe Ee Ed Ee ee Ge 41 BB NCCU TC OCS ME se i ER oe boe meme EE Ede Ee EE DR 42 SB SUF AGE KODES EO OE EE SE EL NCES EE IE AE EO 43 NA NOME SEIN NT NR NR TE 44 CHAPIER6 REMOTE INTERFACE ni 45 6 1 INTRODUC HON S a a a 45 6 2 CONNECTING THE 4176 VIA GPIB INTERFACE aaa nanen ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 45 621 Whe GPIB interface capabilities srera EE ee oek ee GE GER Ge De gek GE SG lad 45 622 NOTES JO FELINA IONES eg eek Pe N GE Ee area eases 46 O29 COmpulr S CONNCCHON EE Sk EE a A in ats 46 0 24 Pie GPIB connection testing see Re ds 46 6 3 CONNECTING THE 4176 VIA RS232 INTER PA CE aaa aaa ee ee ee ee ee ees ee ee ee ee ee ee ee ee ee ee ee ee 47 63L Theks 32 mer dec Capa IES doi list 47 63 2 NOTES for RS must O era A iia 47 033 EConnecinetod COMPU ar ed A A reed aia io tienes shade 49 OJ Checkin CONNCCIIONS MR A SA tate ead A A taal ee eee ita 49 6 4 INPUT ANDIOUTPUT OUELE is Ge ee de ie id 50 6 5 GOMMANDSAND SYNTAX ies ru ee ee O Es 50 OJA RSA MESAS LOMA OI Neue sve i AA tod Par Ana ated 50 KI AA cai Net else watts cage tia aia ot 50 ND 50 O54 ACOMbIRTISCOMNMAMAS e A Meat a BEEN Te ER FEE 50 OLI SOP Of ONIONS RE A hr d 51 6 6 DETAILS OF COMMAND REFERENCE SS ee Gie ee ee aaa 51 BEDER COMANA TULON ee tiene eaten ds 51 CHAPTER BED INTE RAC EE rose dees see ee ees
10. The zener diode D5 and its associated components create a 1 2V reference This voltage level plus AVDD are used to power the temperature compensator 1f attached Refer to schematic 834u 070 sheet 1 10 6 4 Reset UA SWI and QI form the reset circuitry for the micro controller and the display To reset press SW1 Refer to schematic 834u 070 sheet 1 10 6 5 2 5V Reference U2 1s a precision 2 5V reference used by the micro controller during the analog to digital conversion Refer to schematic 834u 070 sheet 1 10 6 6 Download Normal Switch J4 is the switch that allows the download of the instruments firmware Refer to schematic 834u 070 sheet 1 10 6 7 RS 232 Display Switch and RS 232 Driver Receiver U17 is a digital switch that allows the micro controller to send data to the display or to the RS 232 port U16 is a RS 232 Driver Receiver This component converts data to the RS 232 level Refer to schematic 834u 070 sheet 6 83
11. Voy VALHALLA wa SCIENTIFIC Leading Technology in Precision Electronic Measurement amp Calibration Instrumentation A176 Programmable u Ohmmeter User amp Maintenance Manual 8318 Miramar Mall San Diego California 92121 Phone 858 457 5576 Fax 858 457 0127 www valhallascientific com valhalla valhallascientific com VALHALLA SCIENTIFIC INC CERTIFICATION Valhalla Scientific Inc certifies that this instrument was thoroughly tested inspected and found to meet published specifications when shipped from the factory Valhalla Scientific Inc further certifies that its calibration measurements are traceable to the National Institute of Standards and Technology to extent allowed by N LS T s calibration facility Due to continuing product refinement and due to possible parts manufacturer change Valhalla Scientific Inc reserves the rights to change any or all specifications without notice VALHALLA SCIENTIFIC INC WARRANTY STATEMENT The warranty period for this instrument is stated on your invoice and packing list Please refer to these to determine appropriate warranty dates Valhalla Scientific Inc will repair the instrument during the warranty period provided it is return to our repair and calibration facility freight prepaid No other warranty is expressed or implied Valhalla Scientific Inc is not liable for consequential damages Permission and a Return Material Authorization number RMA must be obtained dir
12. calibration Press the CLEAR button if you wish to return to the previous screen TER SCALING RANGE 2 1 SECOND MATCH 0 300002 ST 0000 Se ter ae This step will perform the voltage calibration from 200mQ range to the 20kQ range When the instrument has completed the 300mV cal the screen will prompt the following message SAVE CAL VALUES PRESS ENTER OR CLEAR Step 6 Press ENTER to save the cal values or CLEAR to return to the 300mV cal CALIBRATION COMPLETE PRESS ENTER OR TCM Step 7 Press ENTER to complete the calibration The screen will display Sali SAVING NEW SETUP DATA IN NOVRAM Sense calibration is now completed 72 8 4 1 2 Source Calibration Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Step 18 Step 19 Step 20 Step 21 Step 22 Step 23 Step 24 Short the SENSE HI and SENSE LO using a jumper Connect the digital voltmeter to the main board as follows DVM negative input to TP9 DVM positive input to TP10 Adjust RVI for a DVM reading of 1 0000V Remove the DVM connection and the jumper Select the 2Q range Connect the 4176 to a 1Q standard resistor Adjust RV2 for a display reading equal to the value of the load Select the 2Q range Connect the 4176 to a 1Q standard resistor Adjust RV3 for a display reading equal to the value of the load Select
13. connect to a load Valhalla Scientific Inc offers a number of different test leads that can be used with the Model 4176 and other Valhalla ohmmeter models see chapter 5 for a list of available test leads All ohmmeter test leads are composed of a pair of leads both terminated in a multi stacking dual banana plug It is important to notice the position of the ground maker on the plug Marked side of each banana jack is connected to the current terminals see table 9 Table 9 Connecting test leads to the ohmmeter Connect between SENSE HI and SOURCE HI with the ground maker on the source side Connect between SENSE LO and SOURCE LO with the ground maker on the source side This configuration ensures that current source is carried in the largest conductor of the cable and that the sense input is shielded The opposite end of the lead may vary in style of termination On the following page you will find a description of the three most common terminations used 19 Figure 12 Alligator type clips Figure 14 Dual needle type probes 20 The most common termination is alligator type clips If this is your choice of leads simply connect one clip to one end of your load and the other clip to the opposite side of the load For flat surfaces you can use between two different spring loaded surface probes If this is your choice of leads simply press one probe against one side of the surface of your load making
14. not be evident until the unit is operated or tested to verify conformance with its specifications If the unit fails to operate or fails to meet the performance specifications of chapter 2 notify the carrier s agent and the nearest Valhalla Sales Office Retain the shipping carton for the carrier s inspection DO NOT return equipment to Valhalla Scientific Inc or any of its sales offices prior to obtaining authorization to do so 1 3 Line Voltage Fuse Selection The only adjustments required before placing the unit in operation are l Verify that the instrument has been set for the proper local AC line voltage The AC line voltage is selected via a sliding switch mounted on the rear panel of the ohmmeter Table 1 Line Voltage Limits Nominal Value RMS Allowable Limits RMS 115V 105Vac to 125Vac 230 210Vac to 250Vac Lina Voltage Switch Figure 2 Line Voltage Switch Position 2 Verify that the proper fuse for this voltage has been installed as follows 115Vac 0 250 Amp Slo Blo Fuse 230Vac 0 125 Amp Slo Blo Fuse 1 4 Bench Use The ohmmeter is supplied with all the hardware required for bench use and special instructions for use in this manner are not necessary The user should become familiar with chapters 3 and 4 before attempting to operate the instrument 1 5 Rack Mounting Optional brackets are available for mounting the ohmmeter in a standard 19 equipment rack The rack mount kit consis
15. sure that the surface of the probe is in full contact with the surface of the load Press the second probe against the surface at the oppose side of your load making sure that the surface of the probe is in full contact with the surface of the load For hard to reach surfaces Valhalla Scientific offers three different sets of spring loaded dual needle probes that differentiate in overall size and distance between the needles If this is your choice of leads simply press both the needles of one probe against one end of the surface of your load press both needles of the second probe against the surface at the oppose end of your load 3 6 Range Selection The ohmmeter is designed to automatically start up in Auto Range According to the load the instrument will automatically select the range that will display the measurement with the greatest resolution possible While in auto range the display range window will show AUTO In many applications where the test current is critical the user can manually select a range Teer CURRENT mm a 1A 100mA 10mA 1mA 1004 A Figure 15 Range Key Pad Ranges are easily selected by pressing the appropriate key The range keys are labeled using the value of the range and the respective test current value The range selected will be displayed on the range window To return to the auto range mode press the AUTORNG key on the front panel 3 7 Overload and Safe Mode W
16. synonomous with OHMS Example LOG ON O lt crlt gt space or comma E IE IS 664 ter les LOG ON 4 default L32693 lt erilt gt Lar Is LOG ON 6 LSO ZOI E Possible options responses as if the folloving queries sent Oi sOHMS 1 OHMS ATODI F RONG 2 POO DL 3 ATOD1 RDNG 4 RDNG 5 RDNG RANGE 6 OHMS EXTEMP Setup TC hoad Coetty COMPENSATED OHMS Ret Degress 1 gt EETEMP 2 SS EX TEMP RONG Run TCM ON first 9 LOG PENDING starts when user presses PRINT Power on default OFF 60 OHMS QUERY Responds with reading from the front panel display and causes an immediate update of the conversion so repeated query requests gets most accurate data Send range command or AUTO prior to sending this to get the scaling factor The Ohms omega milli and kilo characters are removed during remote forma CLO evita OHMS 7 Example OHMS lt crlf gt Z0 Aa OOUSGE IT on 20m or 20k Ohm ranges Response 22 0 Oe IG Sea Power on default 0 000 Note For Scientific notation Engineering format use RDNG OES QUERY Returns the option text strings factory installed on meter from non volatile Syntax SOPI Example ORT SEPIE Option s GPIBLIEBRAS908 2 BED PLE HUGE TEM AUTO RozoZ2 USB lt crili gt RANGE COMMAND Selects a resistance current range Syntax RANGE lt range number gt Range number 0 7 1 R20mOHM 2 R200m0HM 3 RZ OHM 4 R20 OHM 9
17. you wish the Run Hold function to use and press ENTER The screen will display RUN HOLD ACTION SET HOLD KEY 1S PKHI ENTER STORING NEV SETUP DATA IN NOVRAM The instrument vvill automatically return to the previous mode 4 6 Print Log Function The Print Log function allows the user to receive the measurements through the instrument s RS 232 or USB interface A thermal printer labeler or the HyperTerminal of a PC can be used to capture the readings The measurements can also be log to an Excel spreadsheet by using a Data Sources Open Database Connectivity ODBC to access data from ohmmeter The Print Log function can be configured in three different ways PRINT When the Print key is pressed the instrument transmits one reading as it is displayed on the ohmmeter s screen LOG When the Print key is pressed the instrument transmits continuously the measurements at a rate equal to the display update rate9 Pressing the once again the print key will terminate the transmission The measurements are transmitted in the same format in witch they are displayed on the ohmmeter s screen LOG2 When the PRINT key is pressed the instrument transmits continuously the measurements at a rate equal to the display update rate Pressing the once again the print key will terminate the transmission The measurements are transmitted in engineering format For example 10 000A4Q 1 00E 04 See section 4 of chapter 4
18. your model We will now outline the use of each of the rear panel controls and connectors RS 232 RECEPTICLE IDENTIFICATION LABOL FUSE HOLDER gt o EN HLC RELAY TERMINAL LINE VOLTAGE SWITCH POWER CONNECTOR Figure 10 4176 Standard Rear Panel 3 3 1 Line Voltage Switch The line voltage switch allows the user to select the power settings according to the local AC line voltage By sliding the switch upwards the number 115 will appear on the switch The instrument is now configured for line voltages of 115VAC 10 By sliding the switch downwards the number 230 will appear The instrument can now be used with line voltages of 230VAC 10 Prior to powering on the ohmmeter it is conscious to verify that the switch is set for the correct line voltage Selecting the incorrect line voltage setting may cause damage to the instrument 15 3 3 2 Fuse Holder The rear panel fuse holder provides access to the main power fuse Fuse values are listed below 115 Vac 0 250 Amp Slo Blo Fuse 230Vac 0 125 Amp Slo Blo Fuse WARNING Replace blown fuses with their exact equivalent only 3 3 3 Power Connector The 3 prong power connector on the rear panel of the ohmmeter is for the application of AC power to the instrument The mating power cord is included with the instrument at time of purchase Refer to chapter 1 section 3 for available voltages and safety precautions 3 3 4 HLC Relay Terminal The HLC relay termina
19. 2 3 Range Selection Keys The seven range keys simply allow the user to select the required measurement range of the ohmmeter The range keys are labeled with the respective range value and current source value RANGE TEST CURRENT 1A 100mA 10mA 1mA 1004 A 104A Figure 7 Range Keys Extra care must be taken when working with inductive loads CAUTION Always select the highest resistance range before connecting or disconnecting the test leads 11 3 2 4 Function Numerical Keys The Function Numerical keys are sixteen and are used to trigger the standard and or optional ohmmeter functions and for data entry In figure 8 shows the key arrangement while table 5 lists a brief description of the keys and its use The Function Numerical keys will be further described throughout this manual UPDATE ADDR LOCAL RUN HOLD PRINT CLEAR AUTO RNG FUNC VIEW RESET ENTER Figure 8 Function Numerical Keys Table 5 Function Numerical Key Description Key Function Description Numerical Value FUNC The FUNC key is used in combination with other keys to change stored settings dae This key is also used as a Forward button to skip through screens The VIEW key is used in combination with other function keys It is used to view VIEW 0 stored settings UPDATE The UPDATE key is used to set and or view display update rate and intensity 1 HLC The HLC key is used to enable or disable the 4176 s internal
20. 25 ENTER INPUT TEMP COEFF 00 PPM C Using the numeric keys input a value for the temperature coefficient followed by the ENTER key To input a negative coefficient press the key For corrections use the CLEAR key After pressing Enter the instrument will display the coefficient that you have typed Check the value and press enter to confirm If the value is incorrect press clear to return to the input screen EINER INPUT REF TEMP dir Using the numeric keys input a value for the reference temperature followed by the ENTER key For corrections use the CLEAR key After pressing Enter the instrument will display the reference temperature that you have typed Check the value and press enter to confirm If the value is incorrect press clear to return to the input screen 26 4 2 4 TCC Temperature Compensator Calibration This procedure 1s used to match a 4176 with its Omni Compensator The Temperature Compensator Calibration must be done in a CAUTION temperature controlled area ERES els OC R S PRESSE cer UR EL CONNECT THE SENSOR AND PRESS ENTER WAIT WHILE SENSOR STABILIZES When the readings stabilize the instrument will automatically skip to the next screen INPUT AMBIENT TEMP EE amp Using the numeric keys input a value for the reference temperature followed by the ENTER key For corrections use the CLEAR key STORING NEW SETUP DATA IN NOVRAM The new values will
21. 7 STB QUERY 64 KEY COMMAND 58 OY TERR tac he 52 KEY QUERY usina 59 ADDRS COMM 1 52 LOCAL COMMAND 60 ADDRS QUERY 0 52 LOG COMMAND 1 60 BCD COMMAND ee 53 OHMS QUERY 0000 61 BCD QUERY 53 RANGE COMMAND 61 CALDATE QUERY 53 RANGE QUERY 62 CNFG COMMAND 54 RDNG QUERY sesse ss 62 CNFG QUERY 54 RESET COMMAND 63 FAULT COMMAND 54 SAVSETUP COMMAND 63 FAULT QUE RY 55 SAVSETUP QUERY 63 HLC COMMAND ss 55 TCM COMMAND ee 65 HELE QUERY isi ei 55 TOM QUERY 0 65 HLCHI COMMAND 56 ae SYST ERR QUERY Sends the System Error value to the remote host Cleared with CLS lt crlt gt Syntax cool SERR Example STE RR SEK Response DE GENE Power on default 0 ADDRS COMM Sets the GPIB address in RAM memory not in non volatile memory syntax ADDRS lt decimal address gt Response SOELE2 Parameter Address number 1 32 decimal Example ADDRS 7 lt crlf gt ADDR Ser ite TOP LI Power on default 10 Note Value can be saved to non volatile memory with SAVESETUP command ADDRS QUERY Sends the GPIB address from RAM data volatile memory in decimal format
22. ASUREMENT MODE ees ses esse ees see se ee se ees ee se ee se ee ee ee ee de ee ee ee se ee ee ee ee ee ee se ee ee ed 22 4 2 TCM TEMPERATURE COMPENSATED MEASUREMENT MODE ees ees sees ee ee ees ee ee ee ee ee ee ee 23 dad OMM COMPENSATO ES baii 24 4 2 2 TCV O ARE EE pr A 24 42 3 TCS Temperature Compensator Setup ss ee Ee ee ee ee ee ee RE nenen ete eee 24 42 4 TCC Temperature Compensator Calibration ee ee ee ee ee ee nn ee ee ee ee 27 4 3 HLC HI LO COMPARATOR MODE ese sees sees ees ee see be se ees ee ee ees see sees se ee ee ee se ee se ee ee ee ee ee nett 28 AA id EE AT EA EE N RE EE ERE OE RE NE 26 AN EO EN EE OE ER RE EE N OE N EE R 29 A GEE ON ie EE EE N bene ee 30 4 4 UPDATE FUNCTION iese ini ns eise se ee ae ooo de be eect ee ee ee eie is ee di 3 4 4 1 Setting the Display Update Rate and Intensity ii 31 4 5 RON HOLD ENE HORNE EE SE N Ee causa e EA ED 32 AJ Configuring he Rum Hold F UNCHON ss ek GE N i 33 4 6 PRINT OGJUNC HON sa es aed oes coe e a 34 461 Configuring the Print Los Function nese is is 35 4 7 VIEW FUNCHON EE N e EE EE EE 36 ALE Usine the View function zsa ee ee ee ee an EE 36 CHAPTER5 OPTIONAL FEATURES AND ACCESSORIES cccccccccccocconcccnononnccconcccccccnccccanananos 39 5 1 OPTION Sra a EE EO AE ER da 39 ILE BED POU OA SERE da Land GE 39 IL RE EE EA EE AE RR EO OE ole N 39 oN BES Na ph e oh DE DE 39 5 2 ACCESSORIES RR TE OE A EA OE 40 IST QOM COMMCNS AION EE N A
23. C mode is selected According to the result of the comparison one of the relays will have its contacts close while the remaining two relays will have contacts open The standard relay contact closure feature allows an automated sorting process to be set up at an economical cost The screw type terminal allows connections to wires or spade lugs Contacts are rated at 100 volts 100mA Truth table of the contacts is listed below Q s symbol represents the load measured value UL is the upper limit and LL 1s the lower limit set by the user Table 10 HLC Truth Table HLC STATE HLC RESULT XLO GO XHI ON LLSOSUL OPEN CLOSED OPEN ON OSLL CLOSED OPEN OPEN ON UL lt Q OPEN OPEN CLOSED OFF LLSOSUL OPEN OPEN OPEN OFF OSLL OPEN OPEN OPEN OFF UL lt Q OPEN OPEN OPEN 28 4 3 2 Setting the Limits Each range has a different set of limits that can be programmed by the user Table 11 lists the default values programmed for each range Once the user sets new values the default settings will be overwritten and the user settings will be stored in memory Table 11 Default Comparator Limits Range Lower Limit Upper Limit 20mQ 10 000mQ 20 000m0 20 0 11000062 0 20000Q 20 1 0000Q 2 0000Q 200 10 000Q 20 000Q 2000 100 000 200 000 2kQ 1 0000kQ 2 0000kQ 20kQ 10 000kQ 20 000kQ To set your custom readings simply select the range that better fits your load and follow this procedure FUNC HLC INPUT HLC MAX VALUE Using the numerical keys enter the v
24. Ge a 66 7 1 G N R s dia 66 IZ BED PIN ASSIGNMIE NES tt ee 66 CHAPTERS ROUTINE MAINTENANCE eg ie Ge een eis es ee de bed EE Ge Ke Ge ed N Gee ee ee GN EE geed dee 69 8 1 GENERAL sr ii Ee NT 69 8 2 REQUIRED TEST EQUIPMEN Daci si er e 69 8 3 PRE CALIBRATION PROCEDURE iss ene ee see eer wean ee ta 69 8 4 AO CALIBRATION PROCEDURE pese en e ie nose A AA 70 AAN SEA AO EE N N EE IE N valla es ER 70 O42 Periodi Maintenae iss A Be Ee ee BOE Gee ER ee we se 19 CHAPTERS SPECIAL PROGCEDURES asses sesse essens ee one N de ke Nee dees se ase eg ode ER N ee sees gee eo ie de ei 76 9 1 NO READING a Ge EG Ge De ei oe 76 9 2 INDUCTIVE LO D ER ER EE EE OE N EE OG HE NE RO EE EE EE N EE N 76 CHAPTER 10 THEORY OF OPERATION ccccccccccccccccccccsccccccccccccccccccsccccccccccccccccccsccsccccoees 77 10 1 LOCALIZING THE PROBLEM ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee TI 10 2 COMPONENT REPLACEMENT aa 77 10 3 GENERAL CIRCUIT DESCRIPTIONS ccccscecceccecesceccecceccecescescecesceecescesescescescescssescescescssuscascescess 78 10 4 TROUBLESHOOTING e e e reen renere ener reven neee 79 10 5 CURRENT SOURCE DETAILED CIRCUIT DESCRIPTIONS cccsccscoccecceccecescescesceceececcescecescaccuscess 80 10 5 1 LO WE ST ne ee ee Cee ee ee GE ee AE rT E en ee A re meee meer SU 10 5 2 Consian Ginreni SOUP Gap SI 10 6 MICRO CONTROLLER BOARD DETAILED CIRCUIT DESCRIPTIONG ccce
25. M TCM mode is described in detail in chapter 4 section 2 Critical to this measurement mode is precise temperature sensing which entails solid and reliable connections between the sensing device and the instrument The temperature sensor receptacle is designed so that the mating connector sensor the Valhalla Scientific Omni Compensator can be inserted only in the proper mating position A red dot on the Omni Compensator and a red tab on the receptacle are met to guide you in the insertion of the connector in the receptacle Omni Compensator Temperature Sensor gt T C MODE FAULT Temperature Sensor Receptacle Figure 9 Temperature sensor TCM LEDs and Receptacle The TCM feature of the 4176 arithmetically calculates the resistance value to display utilizing the ambient temperature and other parameters that will be present in later chapters It is solemn for the user to be aware if the TCM mode is enabled or disabled so that the display reading may be interpreted correctly The green LED labeled T C Mode is the visual indication that the TCM mode is on Keeping an eye on the red LED labeled Fault also as important Fault is the indicator that alerts of missing contacts between the sensor and the instrument Values displayed while the fault indicator is illuminated are not to be CAUTION considered valid in any case The Omni Compensator is an optional accessory to the 4176 See chapter 5 section 2 1 for m
26. NGE 3 5 KEY LOCAL 25 KEY UNKNONN 6 KEY RESET 7 KEY FUNC KEY UPDATE KEY 1 8 KEY ENTER KEY HLC KEY 2 9 KEY DP KEY ADDR KEY 3 10 KEY RANGE 4 KEY RUNHOLD KEY 4 11 KEY 2 KEY PRINT KEY 5 12 KEY RANGE 5 KEY TCM KEY 6 13 KEY 5 KEY AUTO RNG KEY 7 14 KEY RANGE 6 KEY CAL KEY 8 15 KEY 8 KEY BCD KEY 9 16 KEY 6 KEY VIEN KEY 0 1 7 KEY NOTUSED KEY DISPLAY KEY A 18 KEY RANGE 2 KEY mk KEY DP 19 KEY 1 Power on default 0 Note The remote key macro command was developed so our customers can literally perform any action from the remote available to the key press enthusiast This capability is not without restrictions Illegal key sequences may get the machine in a menu you do not expect or cause the meter to not process properly the keys you send Key presses are human interface and therefore not buffered Because of this key delays may be necessary as sending keys too quickly may lose keys _ 58 KEY QUERY Returns the decimal number of the key last key processed by the state machine This query returns any key in the remote mode even if the key ro rocked Out by remote mode ia KEY LOCAL 15 not locked OUE Syntax KEY lt rlt gt 21 eri Response Decimal Key value between 0 24 0 No key pressed 0 KEY NO KEY 20 KEY RANGE 1 1 KEY 0 Zl KEY 4 2 KEY 3 2 KEY RANGE 0 3 KEY CLEAR 23 KEY 7 4 KEY 9 24 KEY RANGE 3 KEY LOCAL 29 KEY UNKNOWN 6 KEY RESET dl KEY FUNC KEY UPDATE KEY 1 8 KEY ENTER KEY HLC KEY 2 9 KEY DP KEY ADDR KE
27. PI 1994 The GPIB interface functions are listed as follows SH1 Source Handshake The 4176 can transmit multilane messages across the GPIB AH1 Acceptor Handshake The 4176 can receive multilane messages across the GPIB T6 Talker Talker interface function includes basic talker serial poll and unaddress if MLA capabilities without talk only mode function L4 Listener The 4176 becomes a listener when the controller sends its listen address with the ATN attention line asserted The power supply does not have listen only capability SR1 Service Request The 4176 asserts the SRQ Service request line to notify the controller when it requires service RLI Remote Local The 4176 responds to both the GIL Go to Local and LLO Local Lock Out interface messages PPO Parallel Poll The 4176 has no Parallel Poll interface function DCI Device Clear The 4176 has Device clear capability to return the device to power on status 45 DTO Device Trigger The 4176 has no Device Trigger interface function CO Controller The 4176 can not control other devices 6 2 2 Notes for GPIB installation When the 4176 is set up with a GPIB system please check the following things Only a maximum of 15 devices can be connected to a single GPIB bus Do not use more than 20m of cable to connect devices to a bus Connect one device for every 2m of cable used Each device on the bus needs a unique device address No two dev
28. R200 OHM 6 RAK OHM 7 R20K OHM A RANGE AUTO Power on default 7 If the range is AUTO auto ranging is selected iG a RANGE QUERY Returns the selected range Syntax RANGE Response Range number 0 7 Q RANGE OFF SAFE MODE 1 R20m0HM 2 R200m0HM 3 RA OHM 4 R20 OHM DF R200 OEM 6 RZK OHM P RE OK OHM A RANGE AUTO Power on default 7 RDNG QUERY Responds with reading from the device in engineering notation Query function also uses an immediate update of the conversion so repeated query requests gets the most accurate data syntax RDNG Example RDNG lt CELT gt 2 4321le 1 lt crlf gt on 20 000 Ohm ranges Response lt value in reduced engineering notation lt crlf gt gt Power on default 0 000e 0 CAUTION Will not work if the transmit interrupt happens to be busy with a display update and the following occurs Remote gt RANGE 6 lt 2k Ohm System gt Places REM in TX buffer Tiny Display System gt Change to R6 System gt Places 2k in TX buffer Tiny Display System gt Formats Display string 1 6543k Remote gt READING system gt Pl aces in TX butter to VED DT characters Remote gt RANGE 4 System gt Change to RA System gt Executes READING query uses Range 4 and last displayed value System gt Places in TX buffer next R characters _ 62 RESET COMMAND Executes a soft reset of the ADuC834 processor system syntax RESET Respo
29. Y 3 10 KEY RANGE 4 KEY RUNHOLD KEY 4 11 KEY 2 KEY PRINT KEY 5 12 KEY RANGE 5 KEY TCM KEY 6 13 KEY 5 KEY AUTO RNG KEY 7 14 KEY RANGE 6 KEY CAL KEY 8 15 KEY 8 KEY BCD KEY 9 16 KEY 6 KEY VIEN KEY 0 13 KEY NOTUSED KEY DISPLAY KEY A 18 KEY RANGE 2 KEY mk KEY DP 19 KEY 1 Usage Keys are polled every 25ms in a timer interrupt This routine changes mode to local and responds with the last key pressed It can sense keys even in remote mode Keys are debounced but are not tested for each menu state In other words sending KEY 4 in a state that does not accept that key will have no effect to change the state In addition if the KEY X commands are sent without enough interval the key handler task will not have executed and the key press can be overwritten by the next key command and the previous one is skipped This is due to no buffering of remote key presses 59 LOCAL COMMAND Returns meter to local mode remote LED off Goto Local syntax LOCAL Returns ser IE Power on default LOCAL mode Notes REMOTE mode is selected when the meter receives a valid character not lt crlf gt Once selected all keys are disabled and will not be scanned Therefore no key beeps with the exclusion of the LOCAL key at the top right of the key pad This key is active in REMOTE mode and will extinguish the REMOTE LED and transition the device to the front panel local user mode LOG COMMAND Selects LOG mode on or off syntax 3 LOG SON OF 0 FE 20
30. alue of the upper limit For corrections use the CLEAR key After entering the value press ENTER The screen will display the following messages NEW HLC HIGH COMPARE At mQ STORING NEW SETUP DATA IN NOVRAM INPUT HLC MIN VALUE e If an error was made while typing the value press Enter to return to the previous screen Otherwise using the numerical keys enter the value of the lower limit For corrections use the CLEAR key After entering the value press ENTER The screen will display the following messages NEW HLC LOW COMPARE mQ 29 STORING NEW SETUP DATA IN NOVRAM Now the limits are set and will be stored in memory Each range has a different set of limits that can be programmed by the user Table 12 lists the default values programmed for each range Once the user sets new values the default settings will be overwritten and the user settings will be stored in memory Table 12 Default Comparator Limits Range Lower Limit Upper Limit 20mQ 10 000mQ 20 000mQ 20 0 11000062 0 20000Q 20 1 0000Q 2 0000Q 200 10 0000 20 0000 2000 100 000 200 000 2kQ 1 0000kQ 2 0000kQ 20kQ 10 000kQ 20 000kQ 4 3 3 HLC ON To start working with the HLC mode simply select the correct range for your application and press the HLC key The screen will briefly display HLC and you ll see one of the three HLC LEDs illuminate It is always good practice to check if the limits set for that particular range meet your s
31. ases the specifications are valid for full Kelvm Four Terminal measurements using connections having less than 20mQ of lead resistance per wire 2 1 Standard Measurement Mode Specifications 0 006 0 012 Table 2 Range Characteristics Maximum Current Current source is 1 Range Fall eae Resolution Source osote Eae 20MQ 20 000mQ 110 1A 20 300000 1040 1A 20 3 00000 100 uO 100mA 200 30 0000 1mO 10mA 2000 300 000 10mQ 1mA 2KO 3 0000kQ 100mQ 100uA 20kQ 30 000kQ 10 10 uA Table 3 Standard Measurement Mode Accuracy 2 4 0 0 The accuracy Range Accuracy of reading of range ll estaa e 24 hours 1 Year Coefficient valid following a 30 minute 5 warm up at an ambient 20mQ 0 006 0 012 0 02 0 02 0 002 C Be 20 0 006 0 012 0 02 0 02 0 002 C ee ee effects of line voltage 20 0 006 0 012 0 02 0 02 0 002 C ae allowed range 200 0 006 0 012 0 02 0 02 0 002 C Temperature coefficient 2000 0 006 0 012 0 02 0 02 0 002 C specified for temperature ranges from 0 C to 15 C 2KO 0 006 0 012 0 02 0 02 0 002 C and 35 C to 50 C 20kQ 0 02 0 02 0 002 C Max of Error 10 10 of Full S
32. ay receives its data directly from the micro controller Keypad Board 4176 701 This section of the ohmmeter contains the keypad and the LED indicators for the TCM and HLC function Keypad The keypad is used to send commands to the micro controller HLC LEDs These LEDs indicate the result of the HLC comparison TCM LEDs These LEDs indicate the status of the temperature compensation mode 10 4 Troubleshooting Use the following guidelines to determine in which circuitry that fault originates e If the fault occurs on one range only then the fault is probably in the current source section Connect the source binding post to an ammeter that can measure up to 1Amp and has a resolution of at least luA Switch through the ranges and check the value of the test current If any given range does not output current check the relay for that specific range or check if one of the range resistors 1s open If the value of the test current is outside of the specified tolerance check the potentiometer for that specific range e If the fault is display related e g missing segments non numeric data etc the first thing to do is reboot the instrument If the problem persists most likely the fault can be traced to the display it self the display cable or the micro controller board e If the fault occurs on all ranges you should verify that the micro controller s ADC is working correctly Select the 20mQ range and apply 10mV to t
33. baud e Parity bit none e Data bit 8 bits e Stop bit 1 stop bit e Data flow control none 6 3 2 Notes for RS232 installation The 4176 1s a DCE Data Channel Equipment device with a 9 pin D type shell RS232 connector located on the rear panel Table 14 shows the 9 pin connector Female with its pin number assignments Figure 17 shows the wiring configuration for DB9 to DB9 When the 4176 is set up with a RS232 interface please check the following points e Many devices require a constant high signal on one or more input pins e Ensure that the signal ground of the equipment is connected to the signal ground of the external device e Ensure that the chassis ground of the equipment is connected to the chassis ground of the external device e Do not use more than 15m of cable to connect devices to a PC e Ensure the same baud rate 1s used on the device as the one used on PC terminal e Ensure the connector for the both side of cable and the internal connected line are met the demand of the instrument 47 Table 14 RS 232 Connector Pin ONE igurat ion Figure 17 Wiring Configuration DBY to DBY EQUIPMENT COMPUTER DB9 DCE DB9 DTE 48 6 3 3 Connecting to a Computer A personal computer with a COM port is the essential facilities in order to operate the 4176 via RS232 interface The connections between 4176 and computer are as follows L Connect one end of a RS232 cable to the computer IL Connect the o
34. be stored in memory ZI 4 3 HLC Hi Lo Comparator Mode Another useful feature of the 4176 is the Dual Limit Comparator HLC This feature helps eliminate operator interpretation of ohmmeter readings Operator error and fatigue are significantly reduced while realizing an increase 1n testing efficiency A common application is receiving inspection of precision resistors by unskilled operators using the HLC mode If for example the resistors to be inspected and tested are 1 KQ 0 1 the 4176 would be set on the DIGITAL COMPARATOR lt gt a 2kQ range the upper limit would be set at 1 0010kQ and ExcEEDLO GO EXcEEDHI the lower limit to 0 9990kQ If measured resistance is within these limits the GREEN indicator will remain illuminated indicating a within tolerance condition If either RED or the YELLOW indicator is illuminated that respective limit has been exceeded and the test sample should be rejected 4 3 1 HLC Relay Terminal The 4176 provides relay closure outputs which can be used to implement an automated batch sorting system for components or products operate counters sound alarms or shut off a process Resistors transformers strain gauges thermocouples and thermistors are a few items which could be individually toleranced in this manner for matching purposes HI LO Comparator Relay Pins XLO GO XHI The HLC relay terminal is internally wired to three relays which are active only when the HL
35. ber gt FAULT ALARM NO FAULT 00 FAULT ALARM OVER TEMP 01 Internal temperature too high FAULT ALARM CAL LIMIT 02 Input level for calibration exceeded timit FAULT ALARM TCM 04 Input level for TCM calibration exceeded LIMITES FAULT ALARM CMD CHAR 08 Unprintable characters received or cmd too long FAULT TXBUF SPACE 10 Low on space in transmit buffer FAULT ALARM TXBUF FULL 20 Serial transmitter butter Eu ll FAULT ALARM RCVBUf FULL 40 Serial receiver buffer full FAULT ALARM NVRAM 80 NV RAM fault Power on default 00 _ 54 FAULT QUERY Returns the alarm bit mapped byte syntax FAULT Response 2 digit Hexadecimal number FAULT ALARM NO FAULT 00 FAULT ALARM OVER TEMP 01 Internal temperature too high FAULT ALARM CAL LIMIT 02 Input level for calibration exceeded KIM FAULT ALARM TCM 04 Input level for TCM calibration exceeded TREES FAULT ALARM CMD CHAR 08 Unprintable characters received or cmd too long FAULT TABUE SPACE LO Low on space in transmit buffer FAULT ALARM TABUE PULL 29 Serial trensmitter butter full FAULT ALARM RCVBUf FULL 40 Serial receiver buffer full FAULT ALARM NVRAM 80 NV RAM fault Power on default 00 HLC COMMAND Selects HLC mode on or off syntax HEG SON QE OER 2 Example HEC ONSE HEG seriT ONS EF IE Power on default OFF Note HLC mode on puts the logic level HLC relays on the rear panel connector and the ranges on the relays outputs for ALE welay contacte descriptions HLC QUERY Re
36. cale of Full Scale Figure 4 200mQ to 20kQ Range Error Graph Figure 3 20mQ Range Error Graph 2 2 Temperature Compensator Mode Specifications Table 4 Temperature Compensator Mode Specifications The accuracy Accuracy P A R AT F specifications listed are ange i T lt 25 C 15 gt 25 C valid following a 30 of reading of range of of reading 4 of range of minute warm up at an ambient temperature 20MQ 10 02 0 07 0 001 0 02 0 07 0 001 Ee Ee 35 C and include the 20 0 02 0 07 0 001 0 02 0 07 0 001 Ee ele variations within the 20 0 02 0 07 0 001 0 02 0 07 0 001 EE 200 0 02 0 07 0 001 0 02 0 07 0 001 Er T indicates the 2000 0 02 0 07 0 001 0 02 0 07 0 001 temperature in C of the test area 2KO 0 02 0 07 0 001 0 02 0 07 0 001 20KO 0 02 0 07 0 001 0 02 0 07 0 001 2 3 General Specifications DID De e 5 digits VFD Ato Conversion Rate ionisere ak esse ea sede id Re ae ee EI 45 conversions seconds Display Update esse see 5 user selections 100msec 200msec 300msec 400msec 500msec Overload AO il N oe 99 95 of range OOIE hie ZO see A 119 95 of range Overload Middies EG estonio oido flashes OVERLOAD Terminal C on Tea br es non sees oie eg Ee OE ke ee De RR Ee EN Four wire Kelvin Test Current Polarity sees sees AR ee eee ee enen ee ee RA ee eee eee Positive flows High to Low Test Cu
37. e measurement terminals energized when not in use PREFACE This manual contains installation operating and programming and configuration information for the Valhalla Scientific Inc Model 4176 Programmable u Ohmmeter The manual consists of the following chapters CHAPTER 1 INSPECTION AND INSTALLATION This chapter contains information on initial inspection bench use and rack mounting instructions It also contains the initial adjustments necessary to start operations CHAPTER 2 SPECIFICATIONS This Chapter lists all the specification applicable to this model CHAPTER 3 GETTING STARTED This chapter covers the fundamentals of ohmmeter operation It shows you how to use the ohmmeter s front amp rear panel how to make connections and describes the display sections and messages CHAPTER 4 MEASUREMENT MODES amp FUNCTIONS This chapter explains how to setup the instrument for all standard measurements temperature compensated measurements and hi lo comparison Also contains information and procedures on how to configure the settings CHAPTER 5 OPTIONAL FEATURES AND ACCESSORIES This chapter lists and describes all the optional equipment and accessories available for this model CHAPTER 6 REMOTE INTERFACE This chapter illustrates the remote capabilities and explains how to send commands to the ohmmeter from remote and how to retrieve data from remote CHAPTER 7 BCD INTERFACE This chapter illustrates the remote capabilities and expla
38. e returned to Valhalla Scientific for calibration traceable to NIST 8 3 Pre Calibration Procedure The calibration adjustments are accessed by removing the top cover of the instrument The locations of the adjustment potentiometers are shown in drawing Ne 4176 700 see chapter 13 Leave the cover in place as much as possible After each adjustment is made the cover should be replaced and the instrument allowed to stabilizing Dangerous AC line voltages exist inside the instrument Use CAUTION caution when making adjustments to avoid contact with these voltages 69 8 4 4176 Calibration Procedure 8 4 1 Standard Calibration The standard calibration consists of three parts sense calibration source calibration and final adjustment The sense calibration and the final adjustment calibration is cover on and automated the instrument will prompt the user throughout the steps The source calibration is performed by adjusting six potentiometers located on the 4176 main board All three calibrations must be performed for a complete calibration of the 4176 8 4 1 1 Sense Calibration Step 1 Press the FUNC key followed by the CAL key The screen will display the following message FUNC CAL CAL KEY OHMS CAL IMA AE Ad EE VI Step 2 Press the CAL key The screen will display the following message GAL APPLY ZERO VOLTS PRESS ENTER OR CLEAR Step 3 Apply a short between the Sense Hi and the Sense Lo binding post Once the short
39. ectly from the factory for warranty repairs No liability will be accepted if returned without such permission Vay VALHALLA Wa SCIENTIFIC 4176 Programmable u Ohmmeter User amp Maintenance Manual Edition 1 Copyright 2004 2005 Valhalla Scientific Inc All rights reserved DOCUMENTATION HISTORY All Editions and Updates of this manual and their creation date are listed below The first edition of the manual is 1 The edition number increases by 1 whenever the manual is revised Updates which are issued between editions contain replacement pages to correct or add additional information to the current Edition of the manual Whenever a new Edition is created 1t will contain all of the update information for the previous Edition Each new Edition or Update also includes a revised copy of this documentation history page OO Ka SE EE EE EA VA HO EN ER EO November 2004 CAUTION SAFETY SYMBOLS Instruction manual symbol affixed to product Indicates that the user must refer to the user manual for specific WARNING or CAUTION information to avoid personal injury or damage to the product Indicates the field wiring terminal that must be connected to ground before operation the equipment protects against electrical shock in case of fault Calls attention to a procedure practice or condition that could possibly cause damage to equipment or permanent loss of data Alternating current AC Ed
40. ed off To avoid dangerous electrical shock DO NOT perform procedures involving cover or shield removal unless you are qualified to do so DO NOT operate damaged equipment Whenever it is possible that the safety protection features built into this product have been impaired either through physical damage excessive moisture or any other reason REMOVE POWER and do not use the product until safe operation can be verified by service trained personnel If necessary return the product to Valhalla Scientific for service and repair to ensure that safety features are maintained DO NOT service or adjust alone Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present DO NOT substitute parts or modify equipment Because of the danger of introducing additional hazards do not install substitute parts or perform any unauthorized modification to the product Return the product to Valhalla Scientific for service and repair to ensure that safety features are maintained Measuring high voltage is always hazardous ALL multimeters input terminals both front and rear must be considered hazardous whenever inputs greater than 42V dc or peak are connected to ANY input terminal Permanent wiring of hazardous voltage or sources capable of delivering grater than 150VA should be labeled fused or in some other way protected against accidental bridging or equipment failure DO NOT leav
41. f necessary 4 8 1 Enabling SafeMode To enable the SafeMode option press the FUNC key followed by the m k key The screen will display the following messages FUNC L_ CU SAFEMODE OPTION ENABLING 4 8 2 Disabling SafeMode If SafeMode is enabled it can simply be disabled by following these steps Disconnect all lead from the binding post and allow the instrument to go in to SafeMode Once in SafeMode press the FUNC key followed by the m k key 38 Chapter 5 OPTIONAL FEATURES AND ACCESSORIES The 4176 u Ohmmeters are shipped with a detachable power cord and an Operation Manual as standard equipment This section lists several items that may be desirable for special applications 5 1 Options 5 1 1 BCD Data Output This option provides parallel BCD data on a rear panel 50 pin connector All outputs are TTL compatible levels with a drive capability of 1 LS load Also refer to chapter 7 9 1 2 GPIB The Valhalla 4176 comes standard with a RS 232 interface Also available is an optional GPIB IEEE 488 2 compatible interface The interface is talk listen and provides range and ohmmeter function control Also refer to chapter 6 9 1 3 USB Another interface that is available is USB The interface is talk listen and provides range and ohmmeter function control Drivers are provided 39 5 2 Accessories 5 2 1 Omni Compensator To be able to use the TCM feature of the 4176 the user will need an Omni Com
42. fault 0 Note After a command or query with or without a response the STB query responds with hexadecimal number with bits mapped as in the table above The STB query clears the command status byte as does any other correctly completed command The bits are sticky through the sending of the STB query response but are cleared after the data is transmitted 64 TCM COMMAND Selects TCM mode on or off syntax TEM SON D OFF gt gt Example TEM ONSGELI TE Mos II ONSerliz Power on default OFF TCM QUERY Responds with TCM mode on or off syntax TCM Example TCM lt erii gt ONSE LI Response STONY or QEr gt Power on default OFF Send this date after the calibration is complete followed by a SAVESETUP to store in EE memory Tol OUERY Causes internal self test to run and returns the result Syntax To Le Response Format a CAUTION THIS FORMAT IS THE ONLY ACCEPTABLE BY IVI DRIVER 65 Chapter 7 BCD INTERFACE 7 1 General Option BCD provides parallel Binary Coded Decimal data output that corresponds to the display indication Signals are also provided for range information and overload A run hold line is also provided to halt the 4176 The signals are TTL compatible 0 lt 8V and 12 2 4V and will drive 1 LS TTL load 7 2 BCD Pin Assignments DATA This is the BCD coded data which is identical to that being displayed by the 4176 NET FUNCTION af a v o w
43. he sense terminal The display should read 10 000mQ Select the 100mQ range and apply 19 100mV to the sense terminals The display should read 100 00mQ Is these values are not displayed try recalibrating the instrument 10 5 Current Source Detailed Circuit Descriptions This series of paragraphs detail the actual operation of the above mentioned circuits and are provide to aid the technician in troubleshooting to component level A basic knowledge of electronics is assumed The technician should refer to the schematics in chapter 13 of this manual 10 5 1 Power Supplies The ohmmeter uses several supplies to power the current source the micro controller and the remaining circuitry All of these supplies are similar in design A secondary winding of the transformer T1 provides the basic AC voltage from which the DC supply will be produced This AC voltage is rectified using diodes filtered using electrolytic and tantalum capacitors and in some cases regulated using a standard three pin regulator The levels supplied are the following 15V and AGND analog ground 8V and OV current source ground 5V DVDD digital 5 volt supply and DGND digital ground 5V AVDD analog 5 volt supply and AGND analog ground AVDD and DVDD are regulated by a precision 5 volt regulator and isolated from each other as shown below 5V AVDD L1 5V DVDD From 5v Regulator C40 10uF 33uF AGND DGND The complete power supply circuitr
44. hen the value of the load exceeds the range limit the instrument will be in an Overload state In cases of overload the display will repeatedly flash the word OVERLOAD If this occurs select a higher range setting or press the Auto key so that the instrument can automatically select the appropriate range If the load value exceeds the limit of the highest range promptly disconnect the load from the instrument to avoid damage to the equipment As a safety precaution the 4176 is designed to switch into Safe Mode if the overload persists for more then 10 seconds In safe mode the 4176 shuts down its current source and displays the word SAFEMODE the screen The ohmmeter does not automatically recover from safe mode the user must press the Enter key to return to measurement mode This is so that the user can be aware that an overload has occurred so that the cause maybe investigated 1f necessary 21 Chapter 4 MEASUREMENTS MODES AND FUNCTIONS The main characteristic of the 4176 1s 4 wire resistance measurements In addition to standard measurements the 4176 presents the TCM and HLC modes These features may significantly ease time and cost of temperature sensitive and automated selection applications 4 1 Standard Measurement Mode The 4176 powers on in the standard measurement mode in this mode the instrument simply measure the value of the applied load using a 4 wire configuration This configuration eliminates errors nor
45. ices can share the same device address e Turn on at least two thirds of the devices on the GPIB system while using the System e Do not use loop or parallel structure for the topology of GPIB system 6 2 3 Computer s Connection A personal computer with a GPIB card is the essential facilities in order to operate the 4176 via GPIB interface The connections between power supply and computer are following L Connect one end of a GPIB cable to the computer IT Connect the other end of the GPIB cable to the GPIB port on the 4176 III Turn on the 4176 IV Turn on the computer 6 2 4 The GPIB connection testing If you want to test whether the GPIB connection is working or not you can send a GPIB command from computer For instance the query command idn should return the Manufacturer model number serial number and firmware version in the following format VALHALLA SCIENTIFIC 4176 1 01G 0 If you do not receive a proper response from the 4176 please check if the power is on the GPIB address 1s correct and all cable connections are active 46 6 3 CONNECTING THE 4176 VIA RS232 INTERFACE 6 3 1 The RS232 interface capabilities The RS232 interface provides a point to point connection between two items of equipment such as a computer and the 4176 There are some parameters you need to set on the both sides Once you have set these parameters you can control the 4176 through the RS232 interface e Baud rate 9600
46. ins how to send commands to the ohmmeter from remote and how to retrieve data from remote CHAPTER 8 ROUTINE MAINTENANCE This chapter illustrates how to perform routine maintenance to the ohmmeter It covers the calibration procedures and fuse replacement CHAPTER 9 SPECIAL PROCEDURES This chapter contains a number of useful tips that should be noted when working with inductive loads CHAPTER 10 THEORY OF OPERATION This chapter describes the theory of operation of the ohmmeter and its features It gives a detailed circuit description and troubleshooting information CHAPTER 11 ADDENDUMS This chapter lists updates and addendums for this manual CHAPTER 12 PARTS LIST This chapter lists all the parts and components used in the manufacturing of the ohmmeter CHAPTER 13 DRAWINGS AND SCHEMATICS This chapter contains all the assembly drawings and schematics for the ohmmeter TABLE OF CONTENTS CHAPTERI INSPECTION AND INSTALLATION cccsscccsssccscccccsccccscccssccccscscccscccsscssseees 4 1 1 INTRODUCTION codes 4 1 2 O EE EE EE EE A 4 1 3 LINE VOLTAGE FUSE SELECTION oe neel ee ase OE E Ge Ge ae DE Ge Ee GE Se 4 1 4 BEN U SE EE ou 5 1 5 E INA EN TN ari 5 1 6 TIT CI MI die si N EE NE EE EE EE EE EE 6 CHAPTER 2 SPECIFICATIONS ii eie ne sees Gee ee GN n ORE ee RGN RR GEE n ee GE ee Rd as GE Re ERG Ee 7 2 1 STANDARD MEASUREMENT MODE SPECIFICATIONS aaa aaa aaa nana ana sees sees ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee a
47. ion converts the AC line power into the DC levels necessary to power the ohmmeter s circuitry Constant Current Source This section of the main board provides a stable test current that is passed through the load to develop a voltage across it The value of this current for each range is indicated on the front panel of the instrument Micro Controller Board 834u 700 This is the central processing unit of the ohmmeter The analog to digital conversion the range selection LED indicator selection and all other decision making processes occur in this portion of the instrument ADC The micro controller s analog to digital converters sense the voltage drop across the load TCM ADC The micro controller s analog to digital converter sense the voltage across the temperature sensor Omni Compensator 78 CPU The micro controller processes the data received by the ADC s and sends a ohms reading to the display Also from the data received from the keypad the micro controller selects the current range activates the LEDs and sends data out from the rs 232 port Current Range Selector The current range selection occurs within the micro controller According to the data received from the keypad a signal is sent to activate the appropriate relay on the current source circuitry RS 232 The RS 232 data 1s also sent and received by the micro controller Display This is the visual interface to the user The displ
48. is 1 inch in diameter a 5 3 3 2 Option MP 5 Surface Probes These probes permit rapid repeatable K bonding testing on a variety of screened or 5 flat surfaces Test current is evenly distributed through the probe base while sensing is accomplished via a spring loaded center contact The target area is Va inch in diameter 43 5 3 4 Other Lead Sets 5 3 4 1 Option BBL Banana to Banana Cable Option BBL is a 48 shielded cable terminated on both ends in dual stacking banana plugs This cable may be used for voltage and current connections to the ohmmeter 5 3 4 2 Option SL 48 Low Thermal Leads Option SL 48 is a 48 shielded lead set terminated in gold plated spade lugs This lead set 1s designed to eliminate problems caused by thermal EMF s and is rated for the maximum output current of IA 44 Chapter 6 REMOTE INTERFACE 6 1 INTRODUCTION The 4176 is a fully interactive automatic measurement system Communication between the 4176 and host computers is easily accomplished The standard RS232 interface or optional GPIB and USB interface provide the capability to automate testing retrieve actual resistance readings in different formats retrieve temperature measurements log data and also calibrate the 4176 6 2 CONNECTING THE 4176 VIA GPIB INTERFACE 6 2 1 The GPIB interface capabilities The GPIB interface of the 4176 corresponds to the standard of IEEE488 1 1987 IEEE488 2 1992 and SC
49. is applied press the ENTER key The ohmmeter will perform the zero calibration for all ranges If the CLEAR key is pressed the display will return to the previous screen While the instrument is zeroing the screen will display the following ENTER ZEROING RANGE 1 1 SECS SETTLING ZERO RNG 1 ST 0000 SEC 12 P 12 70 Range Under Calibration ZERO RNG 1 ST 0000 SEC 12 P 12 Timer Pass Pass indicates the number of passing values that have been measured 15 passing values must be measured before the timer reaches its 100 seconds limit for the calibration to pass When the instrument has completed the zero cal for all the ranges the screen will prompt the following message APPLY 10mV PRESS ENTER OR CLEAR Step 4 Apply 10mV using the voltage standard and press ENTER to start the 20mQ range voltage calibration Press the CLEAR key if you wish to return to the zero cal SCALING RANGE 1 1 SECOND MATCH 10 000m2 ST 0000 ale EE elec 1 Calibration Value 10 000m2 ST 0000 SEC 1 oi Timer Pass Pass indicates the number of passing values that have been measured 15 passing values must be measured before the timer reaches its 100 seconds limit for the calibration to pass 71 When the instrument has completed the 10mV cal the screen will prompt the following message APPLY 300mV PRESS ENTER OR CLEAR Step 5 Apply 300mV using the voltage standard and press ENTER to start the range voltage
50. ise pick up This effect can be significantly reduced by using fully shielded cables It may also be helpful and will cause the settling time to be reduced if the unused windings on transformers being tested can be short circuited during the measurement This will significantly reduce the inductance of the winding under test and will also prevent these windings from producing dangerous voltages during connection and disconnection of the ohmmeter 76 Chapter 10 THEORY OF OPERATION Apparent malfunctions are often the result of misinterpretation of specifications or due to an incomplete understanding of the instrument A thorough review of the operating instructions for this instrument is recommended prior to any component replacement Check to be sure that cables and other test equipment are in good working order before attempting to troubleshoot the ohmmeter The following guidelines have been established to help solve the problems that cannot be eliminated by reviewing the operating instructions 10 1 Localizing the Problem The key to successful troubleshooting is to localize the problem as much as possible before trying to pin the problem down to a specific component Certain questions should be asked such as Does the problem occur on all ranges or on a specific range only The power supplies are also one of the first things that should be checked As it is not possible to anticipate all failure modes of the ohmmeter servicing person
51. l is internally wired to three relays which are active only when the HLC mode is selected According to the result of the comparison one of the relays will have its contacts close while the remaining two relays will have contacts open The standard relay contact closure feature allows an automated sorting process to be set up at an economical cost The screw type terminal allows connections to wires or spade lugs HI LO Comparator Relay Pins XLO GO XHI Contacts are rated at 100 volts 100mA Truth table of the contacts is listed below 2 s symbol represents the load measured value UL 1s the upper limit and LL is the lower limit GO CLOSED OPEN OPEN OPEN OPEN set by the user Table 6 HLC Truth Table HLC STATE HLC RESULT XLO ON LLSOSUL OPEN ON Q lt LL CLOSED ON UL lt Q OPEN OFF LLSOSUL OPEN OFF Q lt LL OPEN OFF UL lt Q OPEN 16 OPEN XHI OPEN OPEN CLOSED OPEN OPEN OPEN 3 3 5 RS 232 Connector The RS 232 serial interfacing is done through the 9 pin female D Sub connector located on the rear panel of the instrument Knowledge of the specific pin functions of the serial connector may be necessary for certain applications table 7 lists the pin assignment for the RS 232 connector Pin Pin Function l No connection Receive Data RxD input Transmit Data TxD output No connection Signal Ground GND No connection No connection No connection O1 oaO INIT NI nA JINN No connectio
52. mally caused by test lead and contact resistances In many applications the contact resistance can exceed the value of the load by several orders of magnitude The 4176 bypasses this potential error source by providing two terminals of constant current and an additional two terminals for LEAD RESISTANCE Contact Resistance OF Or high impedance voltage Contact measurement The result is a Resistance fast accurate resistance measurement of the load independent of the resistance of the current carrying leads LEAD RESISTANCE The figure on the right illustrates how the 4 wire principle is used to eliminate lead wire and contact resistances as potential error sources The internal current source inherently overcomes all series resistance within compliance voltage limits and delivers a precise constant current The internal high impedance DVM senses the voltage drop across the load There is negligible contact and lead resistance error created by the voltage measurement because the high input impedance of the DVM limits current flow in the voltage leads 22 4 2 TCM Temperature Compensated Measurement Mode Valhalla Engineers are pioneers in the technology of accurate measuring devices using recognized formulas that compensate for measurement inaccuracies as a result of environmental changes The TCM feature simulates a constant ambient temperature chamber for materials which are normally subject t
53. n Table 7 RS 232C Connector Pin Assignment 17 3 4 Applying Power Before applying power please refer to chapter 1 section 3 Turn on the ohmmeter by placing the front panel power switch in the ON position If the ohmmeter does not to turn on verify that the instrument 1s connected to the power line If line power is not the problem remove the power cord and check the line power fuse and the line voltage selection switch settings 3 4 1 Power On Default Settings Once you turned on the ohmmeter its power on routine On the display you should see the following messages VSI 4176 pOHMMETER F W VERSION x xxx DONNLOADING DISPLAY MEMORY VALHALLA Y AM SE MEME HE EN Figure 11 Power On Display Messages When the power on routine is finished the ohmmeter will beep twice By design the standard measurement mode the auto range function will be selected automatically to avoid an overload condition if any load is applied to the ohmmeter The power on routine will default the ohmmeter s functions as described in the following table Table 8 Power On default settings Functions Setting Standard Measurement Mode ON Range 20kQ Auto Range Automatic Range Selection ON TCM Temperature Compensation Mode OFF HLC Hi Lo Comparator Mode OFF BCD Binary Coded Decimal Output Mode OFF PIM Printer Log Mode OFF 18 3 5 Connecting a Load to the 4176 The first step in using the ohmmeter is to
54. nel should become familiar with this chapter of the manual to gain a complete understanding of the internal workings of this instrument 10 2Component Replacement If the problem has been identified as a faulty component the accuracy of the ohmmeter can be maintained only if the following precautions are taken e Use only the specified replacement component or its exact equivalent Spare parts can be ordered from your nearest Valhalla Scientific Service Center or from the factory directly by referring to the Valhalla Stock Number listed in the Parts Lists section at the back of this manual e Use only 63 37 grade rosin core electronic grade solder with a 50W or lower maximum power soldering iron e When soldering heat the terminal of the component not the solder Apply solder smoothly and evenly Do not move the component until the solder has cooled Bad solder joints can cause additional problems e Static sensitive parts require special handling procedures Always treat an unknown part as if it were static sensitive did 10 3 General Circuit Descriptions 4176 700 l Power Supply _ Current Source RS 232 BEA ig Current Range Selector play CPU Keypad HLC LEDs TCM LEDs 4176 701 rd The ohmmeter may be divided into four separate parts 4176 Main Board 4176 700 This portion of the ohmmeter contains the power supply and the constant current source Power Supply This sect
55. nse Front panel display show soft reset initiation RESETTING is displayed flashing inverse mode for 300ms while all system configurations are returned to power up default Example KESE Pot Response Celi Notes Resetcpu executes as soft reset of the system by nicely changing the returm stack function and popping it Expect a 5S00ms delay after receiving the linefeed before transmitting next command RST COMMAND sets buffers to power on default Syntax ROTSOE ES Response SO Remote command buffer Serial I O history statistics stability SAVSETUP COMMAND Stores current RAM setup data in NV RAM dels EE SAVSE TUESCIELE gt SAVSETUP QUERY Refreshes the current Setup from NV RAM and then sends it to the remote POLE Syntax SAVORTUR er Response EE EE DD CCO BB AA 99 86 11 66 55 AA S3 22 11 DOSEER FEER OD EE BB AA OO 88 77 TOG So 44 33 22 11 DUSCELES PE BE DR GO BB AA 9900 TT Qo 55 14 39 22 Ll DUSGrLtE gt ETE TE BB AA 99 88 lt crlf gt 63 STB QUERY Returns the command status byte Syntax FOLD Response Command status number 0 OXFF Example STE IERE Ol lt crlf gt Fragment TEM ONS er li STR KOKE TCM AFF lt crlf gt Sl Do returns ERROR GSL Cri TCM SCELTE ON lt crlf gt CMD LAST COMPLETE CMD UNKNOWN CMD MISSING PARAM CMD INVALID PARAM 8 CMD MODE OFF 16 CMD INCORRECT NUMBER PARAMS 32 64 128 CMD CALLAREALPGMR AN HO Il Power on de
56. o return to the standard measurement mode repress the TCM key The display will briefly read TCM OFF 4 2 3 TCS Temperature Compensator Setup As describe in section 1 2 of this chapter the 4176 needs to reference a temperature coefficient and a temperature reference to calculate the compensated value Stored in the instruments memory are six configurations that can be selected The next table illustrates the values associated to each of the configurations 24 i i Temperature Temperature e 3931ppm9 C o aas gt o am Pas Per ma 3 mas Pen The following procedure illustrates how to select one if these configuration and how to setup a customized configuration This procedure does not need to be repeated every time the TCM mode is selected The configuration that is selected or the custom values inputted will be set as default FUNC TCM PRESS 1 FOR TCS PRESS 2 FOR TCC SCUO TCU SS A n FUNC NEXT 1 ENTER sets the CU20 configuration 2 ENTER sets the CU25 configuration 3 ENTER sets the AL20 configuration Press the FUNC key to display the next set of configurations oe 4 AL25 5 AG20 6 AG25 CLEAR PREV FUNC NEXT 4 ENTER sets the AL25 configuration 5 ENTER sets the AG20 configuration 6 ENTER sets the AG25 configuration Press the CLEAR key will return to the previous screen Press the FUNC key to display the next screen Sune 7 CUSTOMIZE CLEAR PREV
57. o varying ambient temperatures When in the TCM mode the temperature sensor the Omni Compensator automatically senses the ambient temperature and compensates the reading to indicate what the actual resistance value should be in a controlled environment usually 20 C The compensated value is calculated with the following equation AR aAT Ry The variation of resistance AR divided by the initial resistance Ro 1s equal to the temperature coefficient of the material a multiplied by the variation of temperature AT Expressed in terms of the resistance R R Ro a T T or R R l a T 7 To better understand our uses of the equation we will now express it in terms of our application Ry Relltalt T Where Rc is the compensated value Rm is the measured resistance TA is the ambient temperature and Tr is the temperature reference The compensated resistance is therefore calculated as follows R M R E Ms beat EE The user can select from a list of temperature coefficients and temperature references The list is based on the most commonly used values The user can also customize these settings with unique values Once the temperature coefficient and the temperature reference are set the instruments task 1s to measure the load resistance and the ambient temperature After all the variables are determined the 4176 automatically calculates the compensated resister value 23 Here is an example
58. of the equation Let s assume that we are measuring a copper wire and we wish to know the resistance value at a temperature of 20 C The temperature coefficient of copper is 0 00393 1Q C If the load measures 1 0000Q and the ambient temperature is 22 5 C l Ro 0 99039 14 003931 22 5 20 The value of the load at 20 C would be 0 09903Q 4 2 1 Omni Compensator The 4176 measures the ambient temperature through a OMNI COMPENSATOR removable external sensor the Omni Compensator This TEMPERATURE SENSOR item does not come standard with the ohmmeter and must be NEG EER purchased separately If the 4176 and the Omni A e Compensator are purchased at the same time the pair will be tal Ad dte calibrated together Each instrument should have a dedicated DS sensor The user cannot interchange sensors between different ohmmeters without prior calibration Calibration will also be necessary if the sensor is purchased as a single item The TCM calibration routine is describe in section 2 4 of this chapter 4 2 2 TCM ON The TCM mode can be selected from the front panel by pressing the TCM function key The display will briefly read TCM ON The instrument will continuously notify the user that the TCM mode is active by lighting the green TCM led on the front panel If the TCM fault LED is also lit discard the displayed measurements and check if the Omni Compensator in properly connected to the front panel T
59. or a certain amount of flexibility when you enter commands The 4176 does not adhere to any friendly listening standards so the commands and queries must be typed as specified 6 5 3 Command Characters The 4176s are not sensitive to the case of command characters You can enter commands in either uppercase or lowercase You can execute any command with preceding white space characters You must use at least one space between the parameter and the command header Subsequent parameters are separated by commas 6 5 4 Combining Commands You can use a semicolon to combine commands but not queries Example RANGE 4 HLCHI 14 999 lt LF gt 50 6 5 5 Synopsis of Commands The tables in this section summarize the commands of the programmable 4176 Ohmmeter 6 6 DETAILS OF COMMAND REFERENCE Each command in this chapter will give a detailed description The examples of each command will be provided and what query form might return Syntax and return values for each are explained in the function header The STB gives the status of the command Remote mode is entered when a valid printable character is received and is exited with the LOCAL front panel key or LOCAL command 6 6 1 Command Index CES COMMAND 53 HLCHI QUERY 56 ADN QUERY cora 57 HLCLO COMMAND 56 RST COMMAND 63 HLCLO QUERY 5
60. ore detail 13 3 2 6 HLC LEDs This portion of the front panel is designated to give the user a visual indication of the HLC results HLC mode DIGITAL COMPARATOR lt gt is described in detail in chapter 4 section 3 The HLC CU fm LEDs are active only when the Hi Lo comparator mode EXCEEDLO GO EXCEEDHI HLC is activated The green LED labeled GO is on if the measured resistance value is between the limits set by the user The yellow LED labeled ExceedLO is on if the measured resistance value is less then the lower limit The red LED labeled ExceedHI is on if the measured resistance value is greater then the upper limit Only one LED can be on at a time if more then one LED is on for any length of time it is recommended that you contact the Valhalla Scientific Tech Support Team 3 2 Remote LED The Remote Led indicates the remote local state of the instrument If the LED Remote is on the instrument is in remote state and can only receive commands C through one of its remote interface ports If the LED is off the ohmmeter is in local state will receive commands only from the front panel keys 3 2 8 Source and Sense Binding Post Connections to the 4176 are made via the front panel source sense terminals which consist of two red and two black standard binding posts I HI HI vvith gold plated brass contact material The posts can accept standard banana plugs wires up to 12 AWG or spade l
61. other than an occasional cleaning of the exterior surfaces of the product and routine performance of the calibration procedure Loose dirt or dust which may have collected on the exterior surface of the ohmmeter may be removed with a soft cloth or brush Any remaining dirt may be removed with a soft cloth dampened in a mild soap and water solution Do not use abrasive cleaners on the ohmmeter The front panel may be cleaned with a soft cloth and a Windex type cleaner if required Do not use petroleum based cleaners on the front panel If required the interior of the product may be cleaned out by blowing with dry compressed air If the product has become heavily soiled with dirt or other contaminants it is recommended that the unit be completely overhauled Contact Valhalla Scientific Calibration Center for details Valhalla Scientific Inc Calibration Center 8318 Miramar Mall San Diego Ca 92121 Phone 858 457 5576 Fax 858 457 0127 e mail valhalla valhallascientific com 75 Chapter 9 SPECIAL PROCEDURES 9 1 Noisy Readings In general noisy readings are caused by poor connections either to the input terminals or to the test load If noisy readings are encountered check these connections first 9 2 Inductive Loads The measurement of highly inductive loads such as large transformers may also yield noisy readings This is due to the very high impedance to line voltage exhibited by the load causing an excessive amount of no
62. pecifications To check the readings press the VIEW key followed by the HLC key The screen will display the both the upper and lower limit set for that range VIEW HLC MAX M2Q MIN mQ To exit the view mode press the VIEW key If the values are correct you can start your measurements Otherwise see section 3 2 of this chapter to set new values 30 4 4 Update Function The Update function is designed to allow the user to set the display update rate and the display intensity The user can chose from a list of five possible display update rates and eight levels of display intensities The display update rate indicates the time interval in between very display update Table 13 lists these values and the equivalent in updates per second Table 13 Display Update Rates display update rate display updates second IS 100msec 10 2S 200msec 5 IS 300msec 3 3 As 400msec 25 SS 500msec 2 The intensity of the display is broken down into 8 levels where level 1 is the least intense and level 8 is the most intense DISPLAY INTENSITY Er 4 3 o 6 7 8 4 4 1 Setting the Display Update Rate and Intensity Press the FUNC key followed by the UPDATE key FUNC pd DISPLAY UPDATE RATE EI N SS ES ES Select a rate using the numerical keys from 1 thru 5 and press ENTER ENTER DISPLAY UPDATE TIME SET FOR mSecs STORING NEW SETUP DATA IN NOVRAM 31 DISPLAY INTENSITY 1 2 3 4 5 6 1 8
63. pensator temperature sensor This item allows the ohmmeter to compensate for temperature variations when testing any material 5 2 2 Option R Rack Mount Adapter The 4176 u ohmmeters may be mounted in a standard 19 equipment rack using a set of optional rack ears Option R comes with all the necessary hardware for installation and mounting An assembly diagram on how to install to rack ears on to the instrument can be found in Chapter 11 of this manual 40 5 3 Test Leads This section details the different test lead sets and connectors available for use with the 4176 u ohmmeters All cables and test leads are manufactured by Valhalla Scientific Inc and are tested before shipping 5 3 1 Alligator Clip Type Leads 5 3 1 1 Option K Kelvin Lead Set Option K is a shielded 4 wire Kelvin cable set 48 inches in length terminated in gold plated alligator clips Option KCS Option K is the recommended general purpose lead set for most applications Option KCS Gold Plated Clips Option KCS are gold plated alligator clips used on the Option K lead set for 4 wire measurements of smaller components and leads Clips open to 1 2 inch and accommodate test currents of up to 10 amperes 5 3 1 2 Option KK Heavy Duty Lead Set Option KK is a 4 wire Kelvin cable set 48 y inches in length terminated in heavy duty gold plated clamps Option JA WS Option JAWS Gold Plated Clamps Option JAWS are gold pla
64. rrent Complianc s V Ola O us des DR cone ais SV minimum D ese Ee eon lactic RS DE GE Ee tea Ode De one De ee DE 300 milliseconds 2 4 Environmental and Power Requirements POW CE DP eat LISVAC or 230VAC 410 50Hz to 400Hz 25VA max Operating Temperature RINGE ndrin vid dd ORERE 0 C to 50 C porade Temporaire IANNIS sei AE Re ee be ee OE ER Ge Re 40 C to 85 C 2 5 Physical Specifications A 80 RH max 40 C non condensing DIMI tit 17 43cm W x 114 29 5cm D x 4 10cm H WI EE OE OR OE 10 36lbs 4 7kg NET 15lbs 7kg SHIPPING If the overload indication is on for approximately 10 seconds the instrument will enter Safe Mode See section 7 of chapter 3 for details Chapter 3 GETTING STARTED 3 1 Introduction This chapter covers the fundamentals of ohmmeter operation It shows how to use the ohmmeter s front amp rear panel how to make connections and describes the display sections and messages Before explaining how to make measurements it 1s useful to describe the sections of the front and rear panel of the 4176 3 2 Front Panel The front panel of the 4176 can be broken down into eight parts In Figure 5 you can see the regions indicated by their name TEMP COMP FUNCTION NUMERICAL KEYS RECEPTACLE amp LEDS SOURCE amp SENSE N BINGING POST REMOTE LED DISPLAY POWER SWITCH HI Lo COMPARATOR LEDS RANGE SELECTION KEYS Figure 5 4176 Front Panel Sections 3 2 1 Power Switch The power
65. scecceccecccesceccecescesceces 82 10 6 1 Mia COP an EGEDE E a orn rates Lee 82 10 6 2 Over oi ARO ON ORE EEN ENE EN KEN 2 10 6 3 A A ON 83 10 6 4 TG e E OE EE N 83 10 6 5 E E TT 83 10 6 6 Download Normal Switch oo ccccccccccccccuccucscccccuccuccuccecuecuecuecuceucsecuecuecucencuecuecueeusescuseuecusencunss 83 10 6 7 RS 232 Display Switch and RS 232 Driver Receiver iese esse sees sees ee ee ee 83 CHAPTER 11 ADDEND UNS EE EO EE N N EO N ENE EE OE EN 84 CHAPTER 12 PARTES LIS EE EE EE EE ON EE RE 85 CHAPTER 13 DRAWINGS AND SCHEMATICS 22 cccccccscscccccccccccccsccscccccccccccscccccssccccceees 94 Chapter 1 INSPECTION AND INSTALLATION 1 1 Introduction Welcome to the world of low resistance measurement The precision instrument you have just purchased offers super stable measurement capability for hard to test 1tems such as transformers coils shunts and even the resistance of wire itself Other features include temperature compensation hi lo comparison and several interface options Please read this manual thoroughly and all accompanying addendums before attempting to operate this ohmmeter 1 2 Inspection If the shipping carton is damaged request that the carrier s agent be present when the unit is unpacked If the instrument appears damaged the carrier s agent should authorize repairs before the unit is returned to the factory Even if the instrument appears undamaged it may have suffered internal damage in transit that may
66. sponds with HLC mode on or off Syntax HEC Example Hit SORLE5 ONSGEIT Response SON OC YORE gt Power on default OFF 55 See chapter 4 section 3 HLCHI COMMAND Sends the Hi Lo Comparator High Limit for current range syntax HLCHI lt value gt Where value 1 0000 for 1 Ohm in the 3 Ohm range and 100 00 for 100m0hm in the 100m Ohm range and 00 500 for 5k Ohms in the 20kOhm range This command writes the value to RAM memory only To store these values in non volatile memory follow with SAVSETUP Send RANGE command before sending this command Must send all 5 digits with leading zeroes Power on default Depends on range HLCHI QUERY Reads the Hi Lo Comparator high value from RAM for range oyntax HUCH IL Response Floating fixed point Ohm value for current range 1 0000 tor N Ohi IR the 2 Ohm Tange and 100 00 for 100m Ohm am the 200m Ohm range This command reads the value from RAM memory only If you have used the HLCHI command to write a HLC value it will be different than the value stored in non volatile memory if the SAVSETUP command has not been sent Power on default Depends on range HLCLO COMMAND Sends the Hi Lo Comparator Low Limit for current range Syntax HLCLO lt value gt Where value 1 0000 for 1 Ohm in the 1 Ohm range 100 00 for 100m Ohm in the 100m Ohm range 1 000 for 1k in the 1k Ohm range This command writes the value to RAM memory only To store
67. switch is a two position ON OFF rocking switch used to apply ON position or disconnect OFF position the AC power source from the internal circuitry of the ohmmeter 10 3 2 2 Display During measurements the display presents 3 windows described in the table below Window Description Measurement Window Displays the measured load value or the temperature compensated value Displays the selected range or the auto range function is on this section of the display will R ance AE do alternate between the automatically selected range and the word AUTO Displays the Valhalla Scientific Logo If a function is activated this section of the display will Function Window i i alternate between the Logo and the abbreviated function name MEASUREMENT WINDOW RANGE WINDOW E En TE RE on Sh ASE AN d EE ee ee a ee T N EL AG A RT HAT eee ee EE AT n Fa I _ E bee 7 bal 4 A A I 5 Fa pa MH ER 2 i se i 1 EE det i L de maal TA LI 3 hg fF nn P EF FR E de Mk GJE E N NN Y k E t UN N Y LR ak EN F i M Q Fa d T as ko m ee A TN od F a Mm i e E x A sq i a a J u ng eines F cmt ar EE F 4 1 d TIRY i ae ees TU A sem 4 od AU dm et SEEM Oog s ST k y x Oa Rarer et e shi kd E sige ar Di Er Ed di Ed e ER ER va Ra n de Har EE a FUNCTION WINDOW Figure 6 Display Window sections The display is also used to prompt the user with alerts and messages 3
68. t amplifier of the current source The range resistors and potentiometers determine the value of the output current The voltage drop across these resistors Vour is used as an input to the Differential Amplifier to provide error correction and to compensate for varying loads 81 10 6 Micro Controller Board Detailed Circuit Descriptions Complete circuitry is shown on schematic 834u 070 sheet 1 thru 7 Keypad Latches U6 U9 32 768kHz 2 BV Ref Oscillator Reset U2 as SW1 U4 Q1 Controller Temp al TCM U1 Over Voltage Sense Protection Input FT da D1 D4 R9 RS 232 Display Switch U17 BCD Latches U10 U12 Indicator Latches U13 U15 Current Selector Latches U5 ly RS 232 E he Driver Receiver To sed U 1 6 RS 232 Connector 10 6 1 Micro Controller J7 To Keypad i J11 To 4176 701 HLC Relays D6 D8 Q2 Q4 Buzzer J6 To 4176 700 The micro controller executes the analog to digital conversion on the voltage across the load Also all other processes such as range selection HLC relay switching LEDs activation and so on Refer to schematic 834u 070 sheet 1 10 6 2 Over Voltage Protection The resistor R9 and diode D1 thru D4 form the Over Voltage protection circuitry This block limits the input voltage to only 7V if an extreme overload occurs Refer to schematic 834u 070 sheet 1 82 10 6 3 TCM
69. ted heavy duty clamps used to terminate Option KK lead set Clamps open to 2 inches for connection to large motors bushings etc MA A ui 5 3 1 3 Option C Banana to Clip Cable mpar 5 3 2 Needle Type Probes Option C is a 48 general purpose shielded lead set terminated on one end in dual banana plugs and on the other end in red and black alligator clips 5 3 2 1 Option MP 1 Kelvin Micro Probes da EF Eer Option MP 1 is a 48 inch shielded 4 wire Kelvin cable set with a 1A test current capacity employing a set of Kelvin Micro Probes spring loaded stainless steel tips with 0 05 spacing The probes are equipped with 5 3 2 2 Option MP 2 Kelvin Mini Probes Option MP 2 is a 48 inch shielded 4 wire Kelvin cable set with a IA test current capacity employing a set of Kelvin Mini Probes The probes are equipped with spring loaded stainless steel tips with 0 18 spacing 5 3 2 3 Option MP S Single Pointed Probe Set Option MP S is a 48 inch shielded cable set with a IA test current capacity employing a set of single pointed handheld pencil type probes 2 wires to each point 5 3 3 Surface Probes 5 3 3 1 Option MP 4 Surface Probes These probes permit rapid repeatable bonding testing on a variety of screened or flat surfaces Test current is evenly distributed through the probe base while sensing is accomplished via a spring loaded center contact The target area
70. the 20Q range Connect the 4176 to a 10Q standard resistor Adjust RV4 for a display reading equal to the value of the load Select the 200Q range Connect the 4176 to a 100Q standard resistor Adjust RVS for a display reading equal to the value of the load Select the 2kQ range Connect the 4176 to a 1kQ standard resistor Adjust RV6 for a display reading equal to the value of the load Select the 20kQ range Connect the 4176 to a 10kQ standard resistor Adjust RV7 for a display reading equal to the value of the load Reset the 4176 from the front panel RESET button or by turning off the power switch and rebooting End of Souse Calibration 73 8 4 1 3 Final Adjustments Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 Select the 20mQ range Connect the 4176 to a 10mQ standard resistor Press FUNC key followed by the CAL key Press the CAL key again to enter the ohms cal mode Press the FUNC key to skip zero volts cal The screen should display APPLY 10mV PRESS ENTER O Press ENTER to continue Once the 10mV cal is complete the screen will display APPLY 300mV PRESS ENTER OR CLEAR Press the FUNC key to skip The screen should display SAVE CAL VALUES PRESS ENTER OR CLEAR Press ENTER to save the cal values Press ENTER to complete the calibration 8 4 2 Periodic Maintenance The 4176 ohmmeter does not require any periodic maintenance
71. ther end of the cable to the RS232 port on the 4176 IT Turn on the 4176 IV Turn on the computer 6 3 4 Checking Connections If you want to test whether the RS232 connection is working or not you can send a command from computer For instance using a terminal program send the query command 1dn should return the Manufacturer model number serial number and firmware version in the following format VALHALLA SCIENTIFIC 4176 1 02C 0 If you do not receive a proper response from the 4176 please check if the power is on and all cable connections are active 49 6 4 INPUT AND OUTPUT QUEUE The design of 64 bytes input queue and 128 bytes output queue for storing the pending commands or return messages is to prevent the transmitted commands of remote control and return messages from missing As the maximum stored capacity for Error Event Queue is 20 groups of messages it should be noted that input data exceeding the capacity by using these buffers will cause data missing 6 5 COMMANDS AND SYNTAX 6 5 1 RS232 message terminators As there is no signal of end message on RS232 bus therefore use LF CR or CR LF as message terminator After the 4176 processes a command a CR LF 1s placed in the output buffer and delivered As for query command the return message of the instrument is also added a LF for PC to judge message terminator 6 5 2 Entering Commands The standards that govern the command set for the 4176 allow f
72. these values in non volatile memory follow with SAVSETUP Send RANGE command before sending this command Power on default Depends on range _ 56 HLCLO QUERY Reads the Hi Lo Comparator low value from RAM for range Syntax HLELO Response Floating fixed point Ohm value for current range 120000 Lor 1 Ohm 11 the 1 Ohm range and 100 000 for 100m Ohm In the 100m Ohm range 1 0000k for 1k Ohm in the 1k Ohm range This command reads the value from RAM memory only If you have used the HLCLO command to write a HLC value it will be different than the value stored in non volatile memory if the SAVSETUP command has not been Sent Send RANGE command before sending this command Power on default Depends on range IDN QUERY Returns the IEEE or RS 232 identification string from non volatile Syntax LDN SERE Response LD String VALHALLA SCIENTIFIC 4176 1 01G 0 Example LDN 2 lt er gt VALHALLA SCIENTIFIC 41706 1 01G 0 lt crlf gt ID STRING VALHALLA SCIENTIFIC VERSION OL OG MODEL gt 417060 HARDWARE VER de OPTION STRING Option es GPIB IEEE4Z88 2 re KEY COMMAND Presses a key from the interface use for macros when the command you desire is not listed here BYE KEY lt key number Response ser Mi only after the key has been processed Key number 0 24 0 KEY NO KEY 20 KEY RANGE 1 1 KEY 0 Zl KEY 4 2 KEY 3 2 KEY RANGE 0 3 KEY CLEAR 23 KEY 7 4 KEY 9 24 KEY RA
73. ts of two brackets plus 4 flat head screws The brackets are easily installed on the front end of each side rail as show in drawing Ne 4176 xxx in chapter 11 The kit is listed in chapter 5 as Option R The size of the ohmmeter and the location of its center of gravity dictate that it must be supported on both sides along its entire length through the use of trays or slides If it is to be transported while mounted in a rack it should be supported so as to prevent upward or downward movement It is recommended that blank panels at least 1 75 inches high be installed between this and any other units in the rack to ensure freedom of air flow Under no circumstances should the ambient air temperature around the unit exceed 50 C while the unit is in operation or 70 C when power is removed 1 6 Safety Precautions The power plug must be a three contact device and should be inserted only into a three contact mating socket where the third contact provides a ground connection If power is provided through an extension cable the ground connection must be continuous Any discontinuity in the ground lead may render the unit unsafe for use The testing of inductive loads such as transformers requires that special precautions be taken to avoid damage to the instrument and or injury to the operator Please refer to chapter 7 Chapter 2 SPECIFICATIONS The specifications for the 4176 Programmable u Ohmmeter are listed in the following paragraphs In all c
74. ugs The four SENSE SOURCE terminals provide full 4 Wire Kelvin measurement capability The right posts are the LO positive and negative current source terminals and provide the test current while the left posts are the positive and negative voltage sense terminals used to monitor the voltage drop across the load The 4 Wire configuration eliminates errors normally caused by test lead and contact resistances In many applications the contact resistance can exceed the value of the load by several orders of magnitude The 4176 bypasses this potential error source by providing two terminals of constant current and an additional two terminals for high impedance voltage sensing The result is a fast accurate resistance measurement of the load independent of the 8 See chapter 4 section 3 2 for detail on how to set the Hi Lo limits 14 resistance of the current carrying leads The Theory of Operation chapter 4 section 1 will illustrate how the 4 wire principle is used to eliminate lead wire and contact resistances as potential error sources 3 3 Rear Panel The rear panel of the 4176 may vary from unit to unit according to the optional features installed This section of the manual refers to the standard model without any optional features or modifications If the 4176 that you are using features terminals or connectors not describe in this section please refer to chapter 9 of this manual for addendums that reference the particularities of
75. y is shown on schematic 4176 070 sheet 1 80 10 5 2 Constant Current Source The constant current source provides the stable current necessary to generate the precise voltage drop across the load The design of the current source compensates for all series resistance within compliance voltage limits to overcome the effects of test lead and contact resistances The complete current source circuitry is shown on drawing 4176 700 sheet 2 10 5 2 1 Reference Generator As a Stable and accurate reference the current source circuitry uses a 6 95VDC regulator U23 The voltage level of the regulator can be checked by measuring the voltage across TP8 and TP9 10 5 2 2 Reference Inverter Stage U24 and its associated components form an amplifier stage having a gain of 144 This stage is used to convert the 6 95 VDC reference voltage to the negative 1 volt reference required by the current source This voltage level can by checked by measuring the voltage across TP10 and TP9 10 5 2 3 Differential Amplifier U25 and its associated components form a unity gain differential amplifier The output of the Reference Inverter stage Vrer and the output of the Output Amplifier Vour form the inputs to this amplifier The output voltage from this amplifier is thus given by Diff Amp Output V our V reg 10 5 2 4 Output Amplifier U26 Q6 Q7 the range resistors R50 through R58 and the potentiometers RV2 through RV7 combine to form the outpu

Model 4176 - Valhalla Scientific, Inc

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