remote control interfaces for do5000 series digital
Contents
1. CONTROL INTERFACES FOR DO5000 SERIES DIGITAL MICROHMMETERS USER MANUAL Issue 7 0 15 October 2002 Cropico Pt No 610017 Ver 7 0 MANUAL HISTORY Issue 2 0 ECN 114 1 3 2000 First draft for RS 232 only Not released Issue 3 0 ECN 128 6 4 2000 Includes IEEE 488 interface Issue 4 0 ECN 119 25 7 2000 Includes PLC interface Issue 5 0 ECN 138 03 11 2000 Reflects new treatment of Temperature Compensated resistance in Version 5 0 software Also includes minor variations for the DO5001 and DO5002 models Issue 6 0 ECN 136 05 02 2001 Includes minor variations for the DO5003 model Issue 7 0 ECN 170 10 10 2002 Includes Settling Algorithm for inductive measurement Includes MEDIUM speed mode Includes adjustable Reference Temperature in Temperature Compensation mode CONTENTS VNTERODUGPSBIQ b bp Ee etian 4 2 5 222 SERIAL INTEREBRGE ee thue uie 4 2 1 bk pid elitti betae tied Eois 4 2 2 Eront Panel Setup ele har tob eM eh 5 2 9 COMMUNICATING tbc bcd ariete adi iecit qe acidi tius 5 3 IEEE 499 PARALEEE INTEREAGE tere tarte dte n eot tbe ttl docu 6 321 SUS A bte Dd get bee til2. SENSe SETTling COUNt lt No of readings gt Sets the maximum number of readings to be taken 2 999 SENSe SETTling COUNt Returns the maximum number of readings selected SENSe SETTling LIMit No of digits Sets the maximum number of display digits by which two consecutive readings may differ for the measurement to be defined as settled SENSe SETTling LIMit Returns the maximum number of display digits selected Selecting the Settling facility will Deselect the Filter facility Change Average AVE Current mode to Positive 41 Current mode Cause an error message if in Fast mode Selecting Filter on Average Current or Fast mode will automatically deselect the Settling facility Open Circuit Voltage Limit Group SOURce VOLTage LIMit LEVel 0 20 50 Sets the open circuit limit to OFF 20mV or 50mV Open Circuit Limits are not available if the or 30KOHM range is selected and attempting to set 20mV or 50mV will generate an execution error and the command will be ignored Attempting to set 20mV or 50mV with AUTO1 or 2 selected will be successful but autorange mode will be turned off and the instrument forced to the current manual resistance range 005003 does not have this facility and attempting to set it will generate an execution error and the command will be ignored SOURce VOLTage LIMit LEVel 20 Returns 0 OFF 20 20mV 50 50mV
3. 005003 does not have this facility and sending this query will generate query error 4 6 System Related Commands DISPlay BRIGhtness lt ON OFF gt or lt 1 0 gt Turns the front panel display backlight on or off Default at power up is on DISPlay BRIGhtness Returns 0 OFF or 1 SYSTem BEEPer Issues a single beep immediately SYSTem BEEPer STATe lt gt or lt 1 0 gt Enables or disables the front panel beeper SYSTem BEEPer STATe Returns 0 OFF or 1 SYSTem VERSion Queries the SCPI version to which the instrument conforms 005000 is not compliant and returns the message NOT SCPI COMPLIANT SYSTem TIME lt hh gt lt mm gt lt ss gt Set the system clock time Use 24 hour clock format SYSTem TIME Queries the system clock time Returns hh mm ss 24 hour clock format SYSTem DATE lt gt lt gt lt gt Set the system calendar date SYSTem DATE Queries the system calendar date Returns IDN Read the instrument s identification string This is of the form manufacturer model no gt lt serial no gt lt software version The serial no field is not used e g 005000 0 3 0 RST Clears all pending operations and resets the instrument to the default RESET condition as described in the instrument user manual with two exceptions 1 No chan
4. Bit Register Reg Operation Complete Ee pe Standard Event 6 ROS MSS pz 40a Operation Reg Condition Event Enable Bit Register Reg Reg Measuring Measurement 23 This reporting system follows the style of SCPI and the unused bits are allocated to other functions which allow for expansion and compatibility with other SCPI compliant devices Questionable Data Registers Temperature Range bit 4 This bit is set when the last measurement resulted in a temperature measurement error eg out of range Resistance bit 9 This bit is set when the last measurement resulted in a resistance measurement error eg over range polarity error excess resistance in current leads Below Lower Limit bit 11 This bit is set when the limits facility is on and the last measurement was less than the lower limit Above Upper Limit bit 12 This bit is set when the limits facility is on and the last measurement was greater than the upper limit The following commands are used to access these registers STATus QUEStionable CONDition Query the Questionable Data Condition Register The instrument returns a binary weighted decimal value representing the bits set in the condition register STATus QUEStionable EVENt Query the Questionable Data Event Register The instrument returns a binary weighted decimal value representing the bits set in the event register and clears it STATus QUEStionable ENABle en
5. CTRLIN NO 1 7 2 pS Se N3 CTRLOUT PASS o FAIL HIGH FAIL LOW EE NN EOT ERROR 33 Figure 3 Connecting the unit with the internal supply PLC SYSTEM DO5000 CTRLIN 4 25V 3 OV 2 COM IN 16 COM OUT 8 CTRLOUT 21 34 Figure 4 Connecting the unit with an external supply PLC SYSTEM DO5000 CTRLIN 4 N3 6 MEASURE 7 COM OUT 8 35 APPENDIX RS 232 IEEE 488 COMMAND SUMMARY Single Wire Interface Messages IEEE 488 Onl DAV Data Valid NRFD Not Ready For Data NDAC Not Data Accepted REN Remote Enable IFC Interface Clear EOI End Or Identify SRQ Service Request ATN Attention Multi Wire Interface Messages ATN Low IEEE 488 Only GTL Go To Local SDC Selective Device Clear GET Group Execute Trigger DCL Device Clear SPE Serial Poll Enable SPD Serial Poll Disable MLA My Listen Address UNL Unlisten MTA My Talk Address UNT Untalk Programming Language Both interfaces use the same commands For the RS 232 interface these commands are sent as part of a serial string For the IEEE 488 interface these commands are sent as a Multi wire Interface Message with ATN High Configuration Commands SENSe FRESistance RANGe range FRESistance RANGe FRESistance MODE lt SLOW MED FAST gt FRESistance MODE SOURce CURRent magnitude current mode SOURce CURRent Trigger and Measurem
6. The Event Register detects 0 to 1 transitions in the Condition Register and the appropriate bit is set The register value can be read at any time using the appropriate query command Reading an Event Register results in all the bits of that register being cleared The Enable Register is a mask which allows any of the bits from the Event Register to set the appropriate bit in the Status Byte Setting an enable bit to 1 enables the event bit clearing the enable bit inhibits the corresponding event bit The register value can be read at any time using the appropriate query command The Standard Event group is similar but consists only of the Event and Enable Registers There is no Condition Register The Output Buffer stores a single line message to be transmitted to the bus This can be up to 80 characters long The message is normally the result of a query command The Status Byte group is used to read a summary of the other registers Note that all Event Registers are cleared after reading but the Condition Registers Enable Registers and Status Byte are left unchanged after reading The Status Reporting System is summarised in the following diagram 22 Questionable Data Reg Condition Event Enable Bit Register Reg Reg m Resistance Below Lower Limit Above Upper Limit Output Buffer Status Byte Standard Event Reg Summary Enable Bit Register Reg Reg Event Enable
7. interface connectors are accessible on the rear panel The RS 232 interface requires Ver 2 0 software or higher The IEEE 488 interface requires Ver 3 0 software or higher The PLC interface requires Ver 4 0 software or higher 2 RS 232 SERIAL INTERFACE 2 1 Connection This conforms to specification ANSI EIA TIA 232 E 1991 Interface Between Terminal Equipment and Data Circuit Terminating Equipment Employing Serial Binary Data Interchange A list of pin assignments is given in Appendix II Signal levels MARK logical 1 3V to 15V SPACE logical 0 3V to 15V Data is transferred using the TXD RXD lines Hardware handshaking for each character transfer uses the RTS and CTS lines RTS is an output from the microhmmeter which indicates its receiver status When asserted low it indicates that it is ready to receive another character When negated high the microhmmeter receiver buffer is full and cannot receive another character until the buffer is processed if the PC sends one it may be lost As soon as space becomes available in the receiver buffer RTS is re asserted to allow the PC to send the next character When the microhmmeter detects receipt of a line terminator character RTS is negated whilst the command line buffer is read and validated This is to prevent the PC sending further characters whilst a command is being validated Following validation RTS is re asserted to permit the next command to be tr
8. REM legend indicates that the microhmmeter is under control of the remote interface The front panel keys will be locked out The MEAS legend indicates that a measurement cycle is in progress For the IEEE 488 interface the TALK LSTN legends indicate that the device has been addressed by the system controller Operation however may be local or remote 28 5 PLC INTERFACE 5 1 Connection Connection to the PLC or similar device is made via the 25 way D connector on the rear panel See Appendix IV for pin details 5 2 Front Panel Set up Press MENU on the front panel select Rem then press PLC The PLC is now selected and the option to select the Analogue Output is given This should be OFF if not required as it will cause a small increase in measurement times For this reason it defaults to OFF at power up Note that once the Analogue Output is ON there is no need for the PLC interface to remain selected if it is not required If no PLC card is fitted the warning message OPTION NOT AVAILABLE is displayed 5 3 Interface Functions The PLC interface allows basic remote control of the microhmmeter by a Programmable Logic Controller or similar device The facilities it provides are Triggering of measurements Selection from 10 stored set up memories which are user programmable via the front panel See main Operation Manual for details Outputs give indication of End of Test M
9. ESE 1 Enables Operation Complete to set the Standard Event bit 5 32 Enables Standard Event to trigger service request CLS Clears the Operation Complete bit DATA START Initiates data logging Sets RQS on completion of the log OPC This command sets the instrument s Operation Complete Query State active When any in progress command is completed the state returns to idle a 1 is placed in the output queue and therefore the Message Available bit 4 is set The command should only be used in conjunction with non query commands and is only available for IEEE If OPC is sent in RS 232 mode it will generate a command error and the command is ignored 27 Example Data logging can take an appreciable time to execute so it is useful to program the instrument to generate a service request on completion of the logging function The following command sequence can be used SRE 16 Enables the Message Available bit to trigger a service request CLS Clears the Message Available bit DATA START Initiates data logging Sets RQS completion of the log Alternatively the application programme can continuously poll the Message Available bit using STB The Status Byte Register can also be read by an IEEE 488 1 serial poll sequence 4 8 Front Panel Operations The currently selected interface is indicated by the RS 232 or IEEE legend Talk Only mode is indicated by the Talk legend The
10. The Status Byte Register contains summary bits from the Questionable Data Standard Event and Operation Registers and also has a single bit reporting the Service Request function for IEEE The Service Request function allows the instrument to request service from the system controller If the same bit is set simultaneously in both the Status Byte Register and the Service Request Enable Register the RQS bit is set in the Status Byte Register and the SRQ service request bus signal is asserted In response to the Service Request the controller will normally be instructed to perform a serial poll sequence on all devices The instrument returns its Status Byte with SRQ set when it is polled The action of reading the Status Byte via the serial poll clears RQS and negates SRQ The following describes the Status Byte Register Messages Questionable Data Summary bit 3 This bit is set when an enabled Questionable Data event has occurred It is cleared by reading the Questionable Data Event Register or by clearing relevant bits in the Questionable Data Enable Register Message Available Summary bit 4 This bit indicates that the Output Queue contains response data It is cleared by reading all data from the output queue or the output queue being flushed by a Query Error or by the CLS command This works for IEEE only the bit is always 0 for RS 232 This bit is particularly useful for synchronising data transfers from the instrument The a
11. abuses pakat tate 6 3 2 Eront P anel Setup aiite bae rat equite 6 3 9 Interface Eurnctlons uie D tiet eee b qa teli thiet ter 6 3 4 Single Wire Interface Messages uie iut utenti i 7 3 5 Multiwire Interface Messages True emm emnes 8 3 6 Device Dependent Messages False eene 10 S26 Serlal Polluim itte ctu aei vea b T Jacke ahold 10 3 8 Parallel tet eme at etel tous 10 4 PROGRAMMING THE RS 232 amp IEEE INTERFACES 4 sees 11 4 1 VAntFodUuCctlora utet bisa 11 4 2 185 232 Interface qusqa tbt Aere add 14 4 3 Configuration 8 Measurement Commands 14 4 4 Data Operation edis dure tbe idi du Aires eed 17 4 5 ditt dure beste a bee e ED HERE A Res EAE 19 4 0 System Relate Commmiands ciem eoim edo Ra CO gre uud 21 4 7 Status Reporting Commands toi eco tico ie anto Rand 22 4 8 Eront Panel Operations tt ade dust dite 28 5 SPECAINTEREACE iuret eet ertet b te t utt ema ters 29 Bilt COMME CTION E Leic
12. 100uS minimum pulse width for IFC End Or Identify When ATN is true the EOI line is used by a controller to execute a parallel poll When ATN is false the EOI line is used by an active talker to indicate the last byte of a data message Service Request This is used by one or more devices to indicate the need for attention and can act as an interruption of the current sequence of events Typically SRQ indicates data is ready to transmit and or an error condition e g syntax error overload trigger too fast etc exists The controller can mask the SRQ interrupt and must perform a Serial Poll of devices when there is more than one to determine who requested service and why Attention devices must monitor at all times and respond to it within 200nS When true ATN places the interface in the Command Mode where all devices accept handshake data on the DIO lines and interpret it as it Commands see Multi wire Interface Messages below When false ATN places the interface in the Data Mode where the active talker sources device dependent Data to all active listeners Addresses are sent over the bus during the Command Mode 3 5 Multiwire Interface Messages ATN True Data transferred on the DIO lines while the controller asserts the ATN line low are bus management commands and device addressing information This is known as Command Mode GTL SDC PPC Go To Local This causes the addressed listener to return to loca
13. in Current leads Yes Yes Open Circuit detected Yes Yes Temperature out of range Yes Yes Settling Algorithm failed to settle Yes Yes Measurement attempted with empty memory No Yes Measurement attempted when Datalog is ON and maximum No of readings has been reached No Yes 5 6 Using the PLC Interface IMPORTANT The PLC must be selected as the Remote Interface See Front Panel Set up When CTRLIN is asserted the Keyboard is locked If no Remote Interface is selected when CTRLIN is asserted then the PLC will be selected automatically If the RS 232 or IEEE is selected a warning message will be displayed together with an intermittent beep and the keyboard remains locked until CTRLIN is released See Figures 1 and 2 for connection details using the internal supply or an external supply To take a measurement Make sure that the microhmmeter is displaying the normal measurement screen Assert CTRLIN Rem appears on the screen Set 0 3 to select the required set up memory See Description of Input Output signals Assert MEASURE Min 10mS CTRLOUT is asserted and remains asserted until CTRLIN is negated NO N3 inputs are read the appropriate memory is selected and the measurement commences Note that if MEASURE remains asserted continuous measurements will occur At the end of the measurement the outputs will be set See Description of Input Output signals Negating CTRLIN will remove Rem f
14. 0 ON or 1 but the instrument response is always 0 or 1 String Parameters contain ASCII characters which are placed between a pair of double quotation marks i e 12 Input Data Format Numeric data sent to the instrument should be in Ohms or degrees unless stated otherwise The value can be in any standard scientific format e g 3KOHM can be sent as 3000 3E3 3 000E3 0 3 4 etc The units are not sent Output Data Format Non Measurement queries ASCII character string Measurement queries IEEE SDDDD DDDESDD If RS 232 SDDDD DDDESDD lt cr gt lt lf gt Where S sign D decimal digit 0 9 E Exponential cr carriage return character If linefeed character Note In IEEE mode the EOI line is also asserted with the transmission of the If terminator Measurement queries always return values expressed in Ohms or Degrees but the units are omitted Resistance values are returned with engineering exponents reflecting the resolution and units displayed on the LCD screen e g Display Returned Value 30 321 0 30 321 300 range 29 657 29 657 3 30 106 45 106 45E 3 200mQ range If a query command results in a command or execution error the error value 9 90E 37 is sent to the output buffer Input Message Terminators In RS 232 mode all messages sent to the instrument must terminate with either a f character or a cr character It is al
15. 450 mS Fast mode 240 mS 5 5 Description of Input Output signals Inputs COM IN Common line for all inputs CTRLIN Requests remote control of the microhmmeter and locks the keyboard When released control will revert to the front panel NO N3 Binary coded data inputs for selection of set up memories N3 N2 N1 NO Memory No 0 0 0 0 0 0 0 0 1 1 0 0 1 0 2 100 1 9 MEASURE Triggers a measurement If closed momentarily a single measurement will result If left permanently closed continuous measurements will result Outputs The links on the PLC card are factory fitted such that the relay contacts will close when an output signal is asserted These can be reversed if required COM OUT Common line for all outputs ACK This signal acknowledges the CTRLIN signal but not until the first MEASURE input is received It then remains asserted as long as CTRLIN is asserted 30 End of Test This is asserted when measurement cycle is completed PASS If the measurement limits are in use then this signal will be asserted with EOT to indicate that the resistance value was within the limits set FAIL LOW HIGH If the measurement limits are in use then this signal will be asserted with EOT to indicate that the resistance value was below above the limits set ERROR This indicates that an error condition occurred during the previous measurement Cause EOT ERROR Overange Yes Yes Polarity error Yes Yes Excess resistance
16. DO5003 model which has fixed current a magnitude of 10 100 must be entered but will be ignored 15 SOURce CURRent Returns the measuring current magnitude and mode currently in force The response is of the following form lt magnitude gt lt current mode containing the appropriate parameter values as above The current measurement is not affected Trigger amp Measure Group These commands trigger measurements and allow the results to be output to the bus INITiate This initiates single measurements The Measurement Available bit 8 of the Operation Condition Register is set on completion The reading is stored internally and is not sent to the output buffer Use FETCh to transfer the value to the output buffer and clear the Measurement Available bit This command is not available when the CONTinuous triggering mode is on nor when DATAlogging mode is on in which cases an execution error will occur TRG This is identical to the INITiate command FETCh FRESistance TEMPerature TCOMpensate Returns the value of the last measurement made This is normally used in conjunction with the INITiate command If CONTinuous triggering is off then INITiate followed by FETCh will be needed for each measurement If CONTinuous triggering is then repeated FETCh commands can be made to return the most recent measurement One of three optional functions can be included with this command FRESistance R
17. a ite 29 52 4 ETON Panel S et up uote ad bet te atia ub tate 29 5 9 Interface Eunctlons ue iue iae tieniti esie allen dee ties tb s 29 5 4 Electrical Characterlstlcs e eite dti be a aso diet aep ter 29 5 5 Description of Input Output signals ete lese de a ee 30 5 6 Using the PLC Interface c cite e tet ie eS to iste 31 5 4 Analogue OULD Ubi tad ient Mila iplum ere ci aptas tes 32 APPENDICES Command Summary II RS 232 Pin Connections IEEE 488 Pin Connections IV PLC Pin Connections 1 INTRODUCTION Two different types of Remote Interface permit full remote control of the microhmmeter by an external computer using either the RS 232 serial interface or the IEEE 488 parallel interface The measured value and instrument status can also be read by the computer The software commands are common to both interfaces and generally follow the IEEE488 2 SCPI format Either or both interfaces can be fitted to the instrument however only one of these can be in use at any one time An additional interface can be fitted which permits more basic control of the microhmmeter by a Programmable Logic Controller PLC or similar device The Analogue Output feature is also included on the PLC card Selection of the optional interfaces together with additional features such as Baud Rate and addresses are set from the front panel menu
18. able value Enable bits in the Questionable Data Enable Register The selected bits are then reported to the Status Byte STATus QUEStionable ENABle Query the Questionable Data Enable Register The instrument returns a binary weighted decimal value representing the bits set in the enable register Standard Event Registers Operation Complete bit 0 This bit is set in response to the OPC command It indicates that the instrument has completed all pending operations This works for IEEE only the bit is indeterminate for RS 232 Query Error bit 2 This bit is set when either an attempt has been made to read data from the output queue when no data is present or pending or data in the queue has been lost This works for IEEE only the bit is indeterminate for RS 232 Execution Error bit 4 This bit is set when a valid command has been received and recognised but could not be executed at the time This could be either an out of context command or an out of range parameter The command is ignored 24 Command Error bit 5 This bit is set when the command line is not recognised by the parser This could be an invalid command parameter or syntax The command is ignored Power On bit 7 Indicates that an off on transition has occurred in the instrument s power supply The following commands are used to access these registers ESR Query the Standard Event Register The instrument returns a decimal value which correspond
19. and 3 Handshake lines The 3 Handshake lines are DAV Data Valid Asserted by the talker to indicate that data has been put onto the data bus NRFD Not Ready For Data Asserted by the listener to indicate that it is busy and is not ready to receive data NDAC Not Data Accepted Negated by the listener to confirm receipt of a data byte 5 General Interface Management Lines REN IFC EOI SRQ ATN Remote Enable This is used only by the System Controller to enable devices to be subsequently placed in the remote programming mode When true all listeners capable of remote operation are placed in remote when addressed to listen When false all devices return to local operation devices capable of both remote and local operation must monitor REN at all times Devices must respond to REN within 100uS The REN command is the only command that will put the instrument into remote mode The front panel keys are disabled and the Rem legend appears on the display The Lstn and Talk legends indicate when the instrument is addressed The instrument may be returned to local operation by sending the GTL command while the instrument is addressed to listen Interface Clear This is used only by the System Controller to halt current operations communications on the bus i e unaddress all talkers and listeners and disable Serial Poll the idle state All devices must monitor IFC at all times and respond within
20. ansmitted by the PC CTS is an input to the microhmmeter and controls the transmission of characters If the PC asserts CTS low then the microhmmeter will transmit the next character from the output buffer if one is waiting If the PC negates CTS high then the microhmmeter will not transmit the character but will wait until CTS is re asserted TXD will remain in the mark low condition whilst CTS is negated Note that changing CTS during transmission of a character will not disrupt the transmission of that character If a 3 wire TXD RXD GND connection is to be used connect RTS to CTS at the microhmmeter end But take care sending characters too quickly to the microhmmeter could cause its receiver buffer 4 characters to overflow and subsequent characters may be lost Always use a time delay between transmitted characters or better still use the full 5 wire connection for reliable hardware handshaking of each character It is recommended that Cropico cable assembly Pt No 100031 be used for connecting the microhmmeter to a PC This has the 5 wire connection and will maintain EMC integrity 2 2 Front Panel Set up Press MENU on the front panel and select Rem I F On the next menu select RS 232 A further menu allows selection of Talk Only mode and Baud Rate If RS 232 option is not fitted the warning message OPTION NOT AVAILABLE is displayed Talk Only Mode This mode is useful for sending re
21. desired listeners are addressed The Lstn legend is turned off Device address 31 is illegal and is the address sent by UNL to unaddress the device MTA Talk Address This is sent by a controller to indicate that it will be the talker from now on All other bus devices must un talk on receiving this command UNT Untalk This unaddresses the current talker Sending an unused talk address would accomplish the same thing This command is provided for convenience since addressing one talker automatically unaddresses another Device address 31 is illegal and is the address sent by UNT to unaddress the device The Talk legend is turned off PPE Parallel Poll Enable Parallel Poll is not implemented This command is ignored PPD Parallel Poll Disable Parallel Poll is not implemented This command is ignored 3 6 Device Dependent Messages ATN False Data transferred on the DIO lines while the controller negates the ATN line high are Device Dependent Messages This is known as Data Mode These messages are described fully in Section 4 3 7 Serial Poll A Serial Poll is a sequence which enables the controller to learn if a device or group of devices requires service and or determine multi bit status of devices on the interface Devices which can be Serial Polled will return a Status Byte requires Talker subset to the controller to indicate their status under program control The controller sequentially polls each individua
22. e The device can receive multiline messages T5 Talker Capability The device can act as a basic talker can respond to a serial poll can perform a talk only mode unaddresses if MLA sent 6 TEO Extended Talker Capability Extended talker addressing is not implemented L3 Listener Capability The device can act as a basic listener can be set to listen only mode becomes unaddressed if MTA sent LEO Extended Listener Capability Extended listener addressing is not implemented SR1 Service Request Function The device can asynchronously assert the SRQ line to request the attention of the system controller RL1 Remote Local Function The device has full remote local switching capability There is no manual switch on the instrument PPO Parallel Poll Function The parallel poll function is not implemented DC1 Device Clear Function The device may be set to the default state by the appropriate command and includes a selective device clear DT1 Device Trigger Function The device may be triggered by the appropriate commands CO Controller Function The controller function is not implemented and hence the instrument cannot behave as a system controller Talk Only mode is available for minimal bus use E2 Driver Electronics lines are tri state outputs except SRQ NRFD and NDAC which are open collector 3 4 Single Wire Interface Messages The IEEE bus consists of 8 data lines 5 General Interface Management Lines
23. easurement within limits Measurement too Low High and Error 25VDC output available to drive inputs and outputs for a self contained system For the DO5001 model it is only available when the instrument is connected to the mains and is not supplied by the internal batteries The analogue Output produces a voltage proportional to the measured resistance value If the Temperature Compensation is selected then this value will be the compensated resistance 5 4 Electrical Characteristics Inputs Number 7 Type optoelectronic Input resistance 1 5 kohms Minimum voltage 11 VDC or 8 VAC Maximum voltage 43 VDC or 30 VAC Outputs Number 6 Type dry contacts Maximum voltage 70 VDC Switch rating 30 W Maximum current 0 15 ADC 29 Logic states Input High state DC or AC voltage with an amplitude between Vmin amp Vmax Input Low state no voltage Output High state closed contact Output Low state open contact Note these can be reversed by altering the position of links on the PLC card 25VDC output This is provided to drive the PLC inputs outputs and is rated at 1 25 ADC For the 005001 model it is only available when the instrument is connected to the mains and is not supplied by the internal batteries Measurement time For a basic resistance measurement the approximate time from the rising edge of the MEASURE line to the EOT end of test signal is Slow mode 700 mS Medium mode
24. eated as a non recognised character and the command error bit 5 of the Standard Event Register is set Semicolon The semicolon is also used to separate command keywords but in this case the path remains at the same level This is to enable more than one command to be included in a single command line This is not implemented for the microhmmeter as only one command per line can be accepted The semicolon is treated as a non recognised character and the command error bit 5 of the Standard Event Register is set Whitespace TAB or SPACE A whitespace character must be used to separate the first parameter from a command keyword If omitted the command error bit 5 of the Standard Event Register is set The microhmmeter will not accept whitespace characters in the subsequent parameter list These will set the command error bit 5 of the Standard Event Register Comma If a command requires multiple parameters a comma must be used to separate parameters from one another in the parameter list 11 Query Commands ending in query 2 indicate that response is expected from the instrument This is usually a measured value or status message Commands sent without a query instruct the instrument to perform a function The instrument will not output a response without a query command except in Talk Only mode Common Commands Commands beginning with a are called common commands and
25. ed It is cleared by reading the Operation Event Register or by clearing the relevant bits in the Operation Enable Register 26 The following commands are used to access these registers STB Query the Status Byte Summary Register The instrument returns a decimal value which corresponds to the binary weighted sum of all bits set in the register SRE enable value Enable bits in the Service Request Enable Register The selected bits are then reported to the Status Byte SRE Query the Service Request Enable Register The instrument returns a decimal value which corresponds to the binary weighted sum of all bits set in the register Other Related Commands CLS Clears the Status Byte Summary Register and all event registers and also resets the Operation Complete Command State and Operation Complete Query State OPC This command sets the instrument s Operation Complete Command State active When any in progress command is completed the state returns to idle and the Operation Complete bit 0 is set The command should only be used in conjunction with non query commands and is only available for IEEE If the OPC is sent in RS 232 mode it will generate a command error and the command is ignored Example Data logging can take an appreciable time to execute so it is useful to program the instrument to generate a service request on completion of the logging function The following command sequence can be used
26. ent Commands INITiate TRG FETCh FRESistance TEMPerature TCOMpensate INITiate CONTinuous lt ON OFF gt or 011 INITiate CONTinuous READ FRESistance TEMPerature TCOMpensate ABORt 36 Data Operation Commands DATAlogger CLEAr COUNt No of readings COUNt STATe lt ON OFF gt 1 0 STATe VALue value number ALL gt POINts Mathematical Operation Commands CALCulate DATA MINimum DATA MAXimum DATA AVERage DATA PTPeak DATA SDEViation CALCulate LIMit LOWer value LIMit LOWer LIMit UPPer lt value gt LIMit UPPer LIMit STATe lt ON OFF gt or lt 1 0 gt LIMit STATe LIMit ALARm lt ON OFF gt lt 1 0 gt LIMit ALARm Temperature Compensation Commands SENSe TCOMpensate STATe or lt 1 0 gt TCOMpensate STATe TCOMpensate MODE lt EXT gt or lt MAN manual temperature gt TCOMpensate MODE TCOMpensate REFerence lt temperature value gt TCOMpensate REFerence TCOMpensate COEFficient lt CU AL gt or USER user coefficient gt TCOMpensate COEFficient UNIT TEMPerature lt C CEL F FAR gt TEMPerature Filter Averaging Commands SENSe AVERage STATe lt ON OFF gt 1 0 AVERage STATe AVERage COUNt No of readings AVERage COUNt 297 Settling Algorithm Commands SENSe SETTling STATe lt gt or lt 1 0 gt SETTling STATe SETTling COUNt lt No of readings gt SETTling COUNt SETTling LIMit No
27. eturns the uncompensated resistance and is the default for the first FETCh TEMPerature Returns the temperature value of the external Pt100 probe providing that temperature compensation is and set to EXT mode Otherwise an execution error is generated and the error value is returned TCOMpensate Returns the compensated resistance value at the reference temperature providing that temperature compensation is Otherwise an execution error is generated and the error value is returned If no function is subsequently entered then the function used in the previous FETCh or READ command is used INITiate CONTinuous lt ON OFF gt or lt 1 0 gt Setting to OFF means that any subsequent READ or INIT followed by FETCh will take one reading and send it to the output buffer If set to ON the microhmmeter will perform continuous measurements which will be initiated immediately and FETCh will send the most recent value to the output buffer The measurements can be stopped by setting CONTinuous to OFF For the 005001 model operating on battery power continuous mode is not available and INITiate CONTinuous ON will cause an execution error to be generated 16 INITiate CONTinuous Returns 0 OFF or 1 READ FRESistance TEMPerature TCOMpensate Triggers and returns a measurement It is identical to INITiate followed by FETCh See the FETCh command above for use of add
28. front panel and select Rem 1 On the next menu select IEEE A further menu allows selection of Talk Only mode or Address If no IEEE card is fitted the warning message OPTION NOT AVAILABLE is displayed Talk Only Mode This mode is useful for sending results directly to a printer without the need for a PC Select to set the Talk Only mode In this mode the interface will ignore all incoming interface commands and the instrument will remain in LOCAL control mode The result of each measurement is sent to the interface output with the same resolution as the main display If the Temperature Compensation is selected then the compensated resistance will be sent See section 4 1 for output data format Addressable Mode On selecting Address Addr the current setting is displayed This defaults to 8 following a RESET operation and is the usual setting on shipment If this is acceptable press To change the value press Chg and enter the new address 0 31 Addresses 0 to 30 are recognised as valid addresses for full bus communication Address 31 is used to isolate an instrument from the bus without the need to disconnect it physically 3 3 Interface Functions The interface performs the following functions SH1 AH1 T5 TEO L3 LEO SR1 RL1 PPO DC1 DT1 CO E2 These have the following meanings SH1 Source Handshake The device can send multiline messages AH1 Acceptor Handshak
29. ge currently in force together with the Autorange mode The response is an ASCII string containing the appropriate parameter values as above The current measurement is not affected The response is an ASCII string of the form range gt auto mode gt where range auto mode 3MOHM to 30KOHM as in tables above AUTO OFF AUTO1 AUTO2 SENSe FRESistance MODE lt SLOW MED FAST gt Sets the measurement mode Slow mode produces approximately two readings per second gives the best noise immunity and all features are available Medium mode gives a 1 5x to 2x improvement in speed Fast mode can produce up to 50 readings per second but some features are not available Average Current Mode Forced to 1 mode Temperature Compensation Forced OFF Settling Algorithm Forced OFF SENSe FRESistance MODE Returns the measurement mode currently in force The response is an ASCII string SLOW MED or FAST SOURce CURRent lt magnitude gt lt current mode gt Sets the measuring current magnitude and mode according to the following parameters The current measurement is aborted lt magnitude gt 10 100 96 current mode 1 AVE AVE current mode is not available in FAST mode Sending this command will generate an execution error The command is ignored and the microhmmeter will remain in the original current mode The Settling Algorithm will be set to OFF if AVE current mode is selected For the
30. ge is made to the remote interface parameters interface type baud rate and IEEE address 2 The trigger mode is set to SINGLE INITiate CONTinuous OFF For IEEE only this also resets the Operation Complete Command State and Operation Complete Query State clears bit 0 of Standard Event Register 21 The default conditions that forced are Range 30KOHM AUTO1 Current 10096 41 Read Rate SLOW Trigger Mode CONT OFF Single STOP Measurement Limits OFF Alarm ON Lower Limit 0 Upper Limit 30KO Filter OFF 10 readings Settling Algorithm OFF 10 readings 10 digits limit Open Circuit Limit OFF Temp Compensation OFF MAN 20 C Cu USER 3980 Ref Temp 20 C Data Logger OFF Count 10 Datalog Memory unchanged READ or FETCh Set to FRESistance Talk Only mode OFF Analogue Output OFF All other functions and parameters are left unchanged by RST TST Always returns 0 to indicate self test OK WAI This command is accepted by both interfaces but ignored as all commands are executed sequentially It is provided only for compatibility with IEEE 488 2 4 7 Status Reporting Commands There are five groups of registers involved The Questionable Data and Operation groups each consist of three registers The Condition Register contains the current status of the instrument and is continuously updated The register value can be read at any time using the appropriate query command
31. have a precise function as defined by the IEEE 488 2 standard instruments behave an identical way These commands are primarily concerned with control reset self test and status Command Syntax Most command keywords have both a long and short form The bus controller can send commands in either form and also in any combination of upper and lower case characters Instrument responses however are always in the short form upper case If extra redundant parameters are sent in a parameter list they are simply ignored No error is produced e g SENSe FRESistance RANGe 300HM 3000HM ignored In the description of commands that follows various symbols are used for different features lt parameter gt represents a field name lt ON OFF gt the vertical bar indicates OR optional square brackets indicate optional commands or parameters string indicates an ASCII text string Data Types The bus controller can also send data in a range of formats but the instrument always responds in a precise format There are four principal data types Numeric Parameters are decimal numbers which include an optional sign mantissa decimal point and exponent Engineering suffix units are not accepted Discrete Parameters have limited values e g SINGle INFinite and like command keywords they can have long and short forms upper and lower case Boolean Parameters have a single binary value The controller can send OFF or
32. itional functions This command is not available when the CONTinuous triggering mode is on nor when DATAlogging mode is on in which cases an execution error will be generated and the error value returned ABORt Stops the current measurement and clears the input and output buffers ABORt works for RS 232 only If sent in 488 mode it will generate command error 4 4 Data Operation Commands DATAlogger Group These commands store and retrieve measurement values using the data logging memory This memory is non volatile and can store up to 4000 readings When the datalog mode is enabled triggering is controlled by the special DATAlogger commands The usual READ INITiate and TRG commands are not available and will generate an execution error DATAlogger CLEAr Clears the datalog memory Take care all the current stored values will be lost DATAlogger COUNt lt No of readings gt Sets the maximum number of readings to be stored Valid range is 1 to 4000 DATAlogger COUNt Returns the maximum number of readings to be stored DATAlogger STATe lt ON OFF gt 110 Enables or disables the datalog function When turned on triggering is controlled by STARt STOP and STEP and all readings are sent to the datalog memory DATAlogger STATe Returns 0 OFF or 1 DATAlogger STARt Forces the continuous measuring mode with all readings being sent to the datalog me
33. l device on the interface sends a SPE if IFC is false and sequentially addresses devices to talk and evaluates each status byte in turn Therefore this procedure can be lengthy in larger systems but does provide the nature of the request at the same time as the identity of the requestor It is advisable though not mandatory to poll every device to be sure to find every requestor and also to send Serial Poll Disable SPD and Untalk UNT at the end of the procedure 3 8 Parallel Poll Parallel Poll is not implemented 10 4 PROGRAMMING THE RS 232 amp IEEE INTERFACES 4 1 Introduction These interfaces are programmed in a common language which is based on SCPI Standard Commands for Programmable Instruments Although similar in style full conformance to the SCPI and 1 488 2 standards is not guaranteed The following is a brief guide to the structure and syntax of the programming language Command Tree Commands are arranged as a hierarchical tree similar to the filing system trees found in personal computers Commands start at the root level and progress down each level in more detail The complete path must be specified to access the lower level commands Colon The colon is used to separate command keywords and automatically move the path down to the next level new command lines automatically start at the root level For the microhmmeter a colon must not be sent as the first character This is tr
34. l panel control exit the REMOTE state The device will return to remote when REN is sent again Selective Device Clear This causes the addressed listener to reset to a device dependent state This is the same as DCL Device Clear but only affects the addressed device Parallel Poll Configure Parallel Poll is not implemented This command is ignored GET TCT LLO DCL PPU SPE SPD MLA UNL Group Execute Trigger This causes all devices which have the GET capability and are currently addressed to listen to initiate a pre programmed action e g trigger take a Sweep etc Some devices may also recognise a device dependent data character or string for this function equivalent but requires entry into Data Mode Sending either GET or TRG will make the microhmmeter perform the INITiate command and take a measurement The command must be sent as a single message Sending either GET or TRG within a command string will result in a command error and the trigger will be ignored Take Control This instructs the addressed device to become the bus controller The microhmmeter is not capable of this function The command is ignored Local Lockout This disables return to local control push button on devices that recognise the command Recognising devices accept the command whether they are addressed or not REN must be set false to re enable the push button this also replaces all devices under local control The microhm
35. meter does not have a manual local button so this command is equivalent to the single wire REN function Device Clear This command causes all recognising devices to return to a pre defined device dependent state Recognising devices respond whether they are addressed or not The effect of DCL is as follows The parser is reset to await a new command The output queue is flushed The instrument is put into the Operation Complete Command Idle State and the Operation Complete Query Idle State Parallel Poll Unconfigure Parallel Poll is not implemented This command is ignored Serial Poll Enable This establishes serial poll mode for all responding talker devices on the bus When they are addressed to talk each responding device will return a single 8 bit byte of status from each device Devices which recognise this command must have Talker interface capabilities to allow the device to output the status byte Serial Poll Disable This terminates serial poll mode for all responding devices returning the devices to their normal talker state when they output device dependent data rather than status information My Listen Address This is sent by a controller to indicate to all other bus devices that it has become a listener Unlisten This unaddresses all current listeners on the bus Single listeners cannot be unaddressed without unaddressing all listeners It is necessary that this command be used to guarantee that only
36. mory Readings are stored sequentially up to the value set by COUNt To start the log at location 1 use CLEAr first If the log has reached the COUNt value any further STARt commands will generate an execution error and the command will be ignored For the 005001 model operating on battery power continuous mode is not available and DATAlogger STARt will cause an execution error to be generated DATAlogger STOP Forces the microhmmeter to STOP mode The current measurement is aborted If the log has not reached the COUNt value STARt or STEP can be used to continue the log from this point 17 DATAlogger STEP Forces a single measurement only which is stored in the next datalog location The microhmmeter then returns to single trigger mode If the log has reached the COUNt value any further STEP commands will generate an execution error The command will be ignored and the microhmmeter will remain in the single trigger mode DATAlogger VALue value number ALL Transfers a datalog reading from the memory to the output buffer A value number of between 1 and POINts will output one reading from that location If ALL is used all readings are sent sequentially to the output buffer from location 1 to POINts Sending ABORt will cancel the operation The output format is record no gt lt range gt lt resistance gt lt date gt lt time gt The range will include the letter z if the Zero f
37. nel are disabled These commands will produce a error in IEEE mode The commands are ignored 4 3 Configuration amp Measurement Commands Configuration Group These commands allow the measurement configuration to be set up but they do not trigger a measurement SENSe FRESistance RANGe range Sets the resistance measurement according to the following parameters The current measurement is aborted DO5000 amp DO5001 range 3MOHM 3 mOhm 30MOHM 30 mOhm 200MOHM 200 mOhm 3OHM 3 Ohm 300HM 30 Ohm 3000HM 300 Ohm 3 30KOHM 30 KOhm AUTO1 Autorange1 top range first AUTO2 Autorange2 last used range first DO5002 lt range gt 300MOHM 300 mOhm 30HM 3 Ohm 300HM 30 Ohm 3000HM 300 Ohm 3KOHM 3 KOhm 30KOHM 30 KOhm AUTO1 Autorange1 top range first AUTO2 Autorange2 last used range first 14 DO5003 range 3OHM 3 Ohm 300HM 30 Ohm 3000HM 300 Ohm 3KOHM 3 KOhm 30KOHM 30 KOhm AUTO1 Autorange1 top range first AUTO2 Autorange2 last used range first and AUTO2 are not available if Open Circuit Limiting is enabled The SKOHM and 30KOHM ranges are also not available if Open Circuit Limiting is enabled Sending these commands in these conditions will generate an execution error The command will be ignored and the microhmmeter will remain in the original range SENSe FRESistance RANGe Returns the resistance ran
38. of digits gt SETTling LIMit Open Circuit Voltage Limit Commands SOURCe VOLTage LIMit LEVel lt OFF 0 20 50 gt VOLTage LIMit LEVel System Related Commands DISPlay BRIGhtness lt ON OFF gt or lt 1 0 gt DISPlay BRIGhtness SYSTem BEEPer BEEPer STATe lt ON OFF gt or lt 1 0 gt BEEPer STATe VERSion TIME lt hh gt lt mm gt lt ss gt TIME DATE lt yyyy gt lt mm gt lt dd gt DATE IDN RST TST WAI Status Reporting Commands STATus QUEStionable CONDition QUEStionable EVENt QUEStionable ENABle lt enable value gt QUEStionable ENABle ESR ESE lt enable value gt ESE STATus OPERation CONDition OPERation EVENt OPERation ENABle lt enable value gt OPERation ENABle STB SRE lt enable value gt SRE CLS 38 RS 232 Interface Commands SYSTem LOCal REMote 39 O G N Q N APPENDIX II RS 232 Pin Connections Data Carrier Detect Received Data Transmitted Data Data Terminal Ready Signal Ground Data Set Ready Request To Send Clear To Send Ring Indicator APPENDIX IEEE 488 Pin Connections DAV ground NRFD ground NDAC ground IFC ground SRQ ground ATN ground LOGIC ground Data Input Output 1 Data Input Output 2 Data Input Output 3 Data Input Output 4 End Or Identify Data Valid Not Ready For Data Not Data Accepted Interface Clear Service Request Attention Data Input Ou
39. pplication programme can poll the bit to detect when a measurement is complete and data is available Alternatively for IEEE the corresponding enable bit in the Service Request Enable Register can be set so that a Service Request SRQ interrupt will occur Standard Event Summary bit 5 This bit Indicates that an enabled Standard Event has occurred 1118 cleared either by reading the Standard Event Status Register by clearing relevant bits in the Standard Event Enable Register or by the CLS common command Request for Service Master Summary Status bit 6 The meaning of this bit depends on how the Status Byte Register is read This works for IEEE only the bit is always 0 for RS 232 RQS This bit forms part of the IEEE 488 1 Service Request function and is valid only during Serial Poll It indicates that the instrument is requesting service It is set when an enabled bit in the Status Byte Register becomes set and cleared by a Serial Poll Assuming no new reason for service occurs the bit will be set for one Serial Poll and clear for subsequent Polls RQS is also cleared if the reason for service disappears for instance when a status register is read MSS When the Status Byte Register is read with STB this bit indicates that an enabled bit in the Status Byte Summary Register is set The bit is cleared when all summary messages are clear Operation Summary Message bit 7 This bit is set when an enabled Operation event has occurr
40. rom the display and unlock the keyboard 31 The PLC interface uses SINGLE trigger mode only If a set up memory which has CONTINUOUS trigger mode stored is selected when using the PLC interface then this will be changed to SINGLE at the start of the first measurement As one of the stored parameters has been altered the MEM number will be removed from the display but all other parameters for that memory will remain correctly set See Figures 3 and 4 for examples of the input and output behaviour during measurement 5 7 Analogue Output This is selected from the Remote Interface PLC menu see Front Panel Set up When fitted and selected ON it produces an output voltage proportional to the measured resistance If the Temperature Compensation is selected then this value will be the compensated resistance For the nominal full scale value for each range 30 000 count this is 3 00V depending on the current direction This facility increases the measurement time by a small amount only significant in FAST mode To avoid it being left ON inadvertently it defaults to OFF at power up 32 Figure 1 Initial measurement using Memory 5 Test failed resistance too high CTRLIN Z NO 1 E 2 m N3 5 MEASURE 3 2 S CTRLOUT PASS FAIL HIGH FALLOW gt 2 27 ERROR ZZ __ Figure 2 Subsequent measurement using Memory 3 Test passed
41. s to the binary weighted sum of all bits set in the register and clears it ESE enable value Enable bits in the Standard Event Enable Register The selected bits are then reported to the Status Byte ESE Query the Standard Event Enable Register The instrument returns a decimal value which corresponds to the binary weighted sum of all bits set in the register Operation Registers Measuring bit 4 This bit is set when a new measurement starts and is cleared when complete Measurement Available bit 8 This bit is set when a new measurement started by the INITiate command has completed The bit is cleared when the FETCh command is used to transfer the value to the output buffer The following commands are used to access these registers STATus OPERation CONDition Query the Operation Condition Register The instrument returns a binary weighted decimal value representing the bits set in the condition register STATus OPERation EVENt Query the Operation Event Register The instrument returns a binary weighted decimal value representing the bits set in the event register and clears it STATus OPERation ENABle enable value Enable bits in the Operation Enable Register The selected bits are then reported to the Status Byte STATus OPERation ENABle Query the Operation Enable Register The instrument returns a binary weighted decimal value representing the bits set in the enable register 25 Status Byte Registers
42. so permitted to send both lt cr gt lt lf gt to terminate a message the If is ignored For IEEE 488 mode messages can be terminated in one of two ways by sending a If character at the end of the message by asserting the EOI line with the last character sent It is also permitted to combine these and assert EOI when sending the If character Message termination always forces the command path back to the root level ready for the next command message 13 Input Buffer The instrument receives messages into an input buffer and only starts executing commands after receipt of a message terminator The buffer can store up to 100 characters including separators and terminator Sending a new command before the existing command is executed may cause unreliable operation It is advisable to query the Status Byte STB to check on the current status of the microhmmeter before sending a new command Sending a command whilst the microhmmeter is transmitting following a command may result in the transmitted response being corrupted It is advisable to wait for the expected response to be transmitted before sending a new command 4 2 RS 232 Interface Commands SYSTem LOCal Returns the instrument to the local mode from RS 232 operation keys on the front panel are fully functional This is the default at power up SYSTem REMote Places the instrument in the remote mode for RS 232 operation All keys on the front pa
43. stance measurements are compensated normally 20 C It is entered in the current temperature unit C or F Range is 0 50 C 32 122 F in integer values of C or the F equivalent SENSe TCOMpensate REFerence Returns the reference temperature in the current temperature unit SENSe TCOMpensate COEFficient CUJAL or USER user coefficient Sets the temperature coefficient to Copper Aluminium or to a user defined value which is entered in ppm C 0 9999 SENSe TCOMpensate COEFficient Returns CU lt fixed copper coefficient or AL lt fixed aluminium coefficient or USER user coefficient The coefficients are quoted in ppm C UNIT TEMPerature lt C CEL F FAR gt Sets the temperature unit to Celsius or Farenheit UNIT TEMPerature Returns CEL or FAR 19 Filter Averaging Grou SENSe AVERage STATe lt ON OFF gt lt 1 0 gt Enables or disables the filter rolling average facility SENSe AVERage STATe Returns 0 OFF or 1 ON SENSe AVERage COUNt No of readings Sets the number of readings to be filtered or averaged 1 32 SENSe AVERage COUNt Returns the number of readings to be filtered averaged Selecting Filter on will automatically deselect the Settling facility Settling Algorithm Group SENSe SETTling STATe lt ON OFF gt or 1 0 Enables or disables the Settling facility SENSe SETTling STATe Returns 0 OFF or 1
44. sults directly to a printer without the need for a PC Select to set the Talk Only mode In this mode the interface will ignore all incoming interface commands and the instrument will remain in LOCAL control mode The result of each measurement is sent to the interface output with the resolution as per the main display If the Temperature Compensation is selected then the compensated resistance will be sent See section 4 1 for output data format Baud Rate On selecting Baud Rate the current setting is displayed This defaults to 9600 following a RESET operation and is the usual setting on shipment If this is acceptable press To change press the up down arrow keys until the required rate is displayed Valid rates are 75 110 150 300 600 1200 2400 4800 9600 amp 19200 Baud These set the Baud rate for both transmit and receive The data word format is fixed at Start bit 1 Data word length 8 bits Parity checking None Stop bit 1 Software handshaking using XON XOFF is not implemented 2 3 Communicating In order to communicate with the DO5000 using RS 232 the command SYSTem REMote must first be sent see RS 232 Interface Commands 3 IEEE 488 PARALLEL INTERFACE 3 1 Connection This conforms to specification ANSI IEEE Std 488 1 1987 Digital Interface for Programmable Instrumentation A list of pin assignments is given in Appendix Ill 3 2 Front Panel Set up Press MENU on the
45. te LIMit LOWer Returns the lower measurement limit in Ohms CALCulate LIMit UPPer lt value gt Sets the upper measurement limit The value is in Ohms 0 30 000 18 CALCulate LIMit UPPer Returns the upper measurement limit in Ohms CALCulate LIMit STATe lt ON OFF gt or lt 1 0 gt Enables or disables the measurement limit facility CALCulate LIMit STATe Returns 0 OFF or 1 CALCulate LIMit ALARm lt ON OFF gt or lt 1 0 gt Enables or disables the failed limit audible alarm CALCulate LIMit ALARm Returns 0 OFF or 1 4 5 Other function Commands Temperature Compensation Group SENSe TCOMpensate STATe lt ON OFF gt or lt 1 0 gt Enables or disables the temperature compensation facility Temperature compensation is not available in FAST mode Attempting to set the state ON will generate an execution error SENSe TCOMpensate STATe Returns 0 OFF or 1 SENSe TCOMpensate MODE lt EXT gt or MAN manual temperature Sets the temperature of the test piece to either an external Pt100 probe measurement or to a fixed manually entered temperature the unit of which is the current temperature unit C or F Range is 0 100 C 32 212 F SENSe TCOMpensate MODE Returns EXT or MAN manual temperature SENSe TCOMpensate REFerence temperature value Sets the reference temperature This is the temperature to which resi
46. tput 5 Data Input Output 6 Data Input Output 7 Data Input Output 8 Remote Enable 40 not connected input output not connected not connected output input not connected O APPENDIX IV PLC Pin Connections No Connection MEASURE COM OUT FAIL HIGH PASS ANALOGUE OUTPUT LOW CASE No Connection No Connection No Connection COM IN NO N2 Spare Input FAIL LOW CTRLOUT EOT ERROR ANALOGUE OUTPUT HIGH No Connection 41
47. unction was used on a measurement and the letter T if Temperature Compensation was used DATAlogger POINts Returns the number of readings actually stored in the datalog memory The response will be between 0 and COUNt CALCulate DATA Group These commands perform statistical calculations on the current contents of the data log A minimum of 2 readings must be stored otherwise an execution error is generated i e bit 4 of the Standard Event Register is set This error is also generated if the log contains inconsistent entries e g readings taken on different ranges CALCulate DATA MINimum Returns the minimum resistance value stored in the data log CALCulate DATA MAXimum Returns the maximum resistance value stored in the data log CALCulate DATA AVERage Returns the average of all resistance values stored in the data log CALCulate DATA PTPeak Returns the peak to peak value of the resistance values stored in the data log i e max to min CALCulate DATA SDEViation Returns the standard deviation of the resistance values stored in the data log This is effectively a measure of rms noise CALCulate LIMit Group These commands are used to set and query the lower and upper limit values used to test the measured resistance Exceeding these limits is reported in the Questionable Data Register bits 11 amp 12 CALCulate LIMit LOWer value Sets the lower measurement limit The value is in Ohms 0 30 000 CALCula
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