Keithley 6487, User Manual

Page 1: ...c i a n sw i t ho v e r 1 5 0y e a r so f s p e c i a l i z a t i o n 9 0d a yw a r r a n t y 5d a yr i g h t o f r e t u r no na l l e q u i p me n t 1 3y e a r w a r r a n t i e sf o r n e wa n d p...

Page 2: ...Model 6487Picoammeter Voltage Source User s Manual A G R E A T E R M E A S U R E O F C O N F I D E N C E...

Page 3: ...INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS INC HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMA...

Page 4: ...Model 6487 Picoammeter Voltage Source User s Manual 2002 Keithley Instruments Inc All rights reserved Cleveland Ohio U S A First Printing October 2002 Document Number 6487 900 01 Rev A...

Page 5: ...incorporate immediately into the manual Addenda are numbered sequentially When a new Revision is created allAddenda associated with the previous Revision of the manual are incorporated into the new R...

Page 6: ...ected to mains voltage or to voltage sources with high tran sient over voltages Installation Category II connections require protection for high transient over voltages often associated with localAC m...

Page 7: ...ersonal contact with these voltages The WARNING heading in a manual explains dangers that might result in personal injury or death Always read the associated information very carefully before performi...

Page 8: ...1 7 Rear panel summary 1 10 Voltage source 1 12 Analog output 1 12 Digital I O 1 12 Display 1 12 Status and error messages 1 12 Power up 1 13 Line power connection 1 13 Line frequency 1 13 Power up se...

Page 9: ...3 2 Voltage source 3 2 Performance considerations 3 3 Warm up period 3 3 Voltage offset correction 3 3 Autozero 3 3 Zero check and zero correct 3 3 Current measurements 3 5 Procedure 3 5 SCPI program...

Page 10: ...e 5 2 Front panel relative 5 2 SCPI programming relative 5 2 mX b m X b reciprocal and Logarithmic 5 3 mX b and m X b 5 3 Logarithmic 5 3 Configuring math functions 5 4 SCPI programming mX b m X b and...

Page 11: ...A Specifications B General Measurement Considerations Measurement considerations B 2 Ground loops B 2 Triboelectric effects B 3 Piezoelectric and stored charge effects B 3 Electrochemical effects B 4...

Page 12: ...ose test fixture connections 2 7 Figure 2 7 Typical connections for measurements using the Model 8009 test fixture 2 7 Figure 2 8 Interlock connections 2 9 Figure 2 9 Typical analog output connections...

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Page 14: ...3 10 Table 3 6 Voltage source current limits 3 12 Table 3 7 SCPI commands voltage source 3 13 4 Range Units Digits Rate and Filters Table 4 1 Measurement ranges 4 2 Table 4 2 SCPI commands range and...

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Page 16: ...zes the features of Model 6487 Front and rear panel familiarization Summarizes the controls and connectors of the instrument as well as providing information on the front panel display Power up Covers...

Page 17: ...nts and Sourcing Voltage Section 4 Range Units Digits Rate and Filters Section 5 Relative mX b m X b reciprocal and log Section 6 Buffer and Sweeps Section 7 Remote Operation and Commands Appendices t...

Page 18: ...ath Always read the associated information very carefully before per forming the indicated procedure The CAUTION heading used in this manual explains hazards that could damage the instrument Such dama...

Page 19: ...his is a 3 slot male to dual 3 lug female triax tee adapter for use with 7078 TRX triax cables Suitable for use with the Model 6487 V Source in high voltage applications Model 237 TRX TBC Connector Th...

Page 20: ...del 6487 CS 459 4 pin Female Interlock Connector Allows custom wiring of external circuits to the Model 6487 interlock GPIB RS 232 and trigger link cables and adapters Models 7007 1 and 7007 2 shielde...

Page 21: ...da Additional references While reading this document you may find it helpful to consult the following documenta tion for reference Model 6487 Reference Manual Supplied in electronic format on the Prod...

Page 22: ...ote interface Model 6487 can be controlled using the IEEE 488 interface GPIB or the RS 232 interface Section 7 Voltage source Internal 500V voltage source is also used for ohms function Section 3 GPIB...

Page 23: ...nts voltage source value 3 Operation keys COMM Use to control and modify communication properties GPIB or RS 232 DISP Use to turn display on off TRIG Trigger measurement s Takes 6487 out of idle state...

Page 24: ...k Readings being stored in buffer more Indicates additional selections are available AUTO Autorange enabled BUFFER Recalling readings stored in buffer ERR Questionable reading or invalid cal step FAST...

Page 25: ...l 6487 Figure 1 3 Mates to a three slot male triax connector cable Figure 1 3 Input connector 120 LINE RATING 50 60Hz 50 VA MAX INPUT CHANGE IEEE ADDRESS WITH FRONT PANEL MENU IEEE 488 CAT I TRIGGER L...

Page 26: ...8 IEEE 488 Connector for IEEE 488 GPIB operation Use a shielded cable such as Models 7007 1 and 7007 2 9 V SOURCE OUTPUT HI This standard banana connector provides HI connection to the 6487 s voltage...

Page 27: ...efer to Section 8 of the Model 6487 Reference Manual Display Readings can be displayed in engineering units or scientific notation Annunciators indi cate various states of operation See Front panel su...

Page 28: ...power cord supplied with the Model 6487 contains a separate ground terminal for use with grounded outlets When proper connec tions are made instrument chassis is connected to power line ground throug...

Page 29: ...elf tests the firmware revision levels are displayed For example 6487 A01 3 After the firmware revision levels are displayed the detected line frequency is displayed For example FREQ 60Hz 4 After the...

Page 30: ...setup is saved into the USR0 USR1 and USR2 setups Saving user setups To save a user setup configure Model 6487 for the desired measurement application then press SAVE and select the desired setup 0 US...

Page 31: ...ving Display Resolution DIGITS 5 digits Format byte order Swapped Normal Function Amps GPIB Address Language No effect On at factory No effect 22 at factory No effect SCPI at factory Limit Tests Limit...

Page 32: ...Units No effect Voltage Source Operate Amplitude Range Current Limit 10V Range Interlock Sweeps Start Voltage Stop Voltage Step Voltage Center Voltage Span Voltage Delay Off 0V 10V 25mA Off 0V 10V 1V...

Page 33: ...nual SCPI commands are listed in tables and additional information that pertains exclusively to remote operation is provided after each table The SCPI tables may refer ence you to other sections of th...

Page 34: ...ncluded in the program message Programming examples in this manual use the short form and do not include optional command words for simplicity Query commands Most command words have a query form A que...

Page 35: ...1 20 Getting Started Model 6487 User s Manual...

Page 36: ...d ohms measurements Using a test fixture Discusses using general test fixtures as well as the Model 8009 test fixture Interlock Provides information on using the interlock which must be used to optimi...

Page 37: ...ector is a 3 lug female triax connector Figure 2 1 Make con nections using a male terminated triax cable Figure 2 1 Triax input connector Voltage source output connectors The rear panel V SOURCE OUTPU...

Page 38: ...leads When making precision measurements you should always use low noise triax cables for INPUT connections As a general rule always use the shortest possible cable for measure ments When using the v...

Page 39: ...rnal voltage source be sufficiently low impedance and capable of carrying the short circuit current of the source in order that the LO not exceed 505V CAUTION Current limiting resistors are required f...

Page 40: ...ill be present in the test circuit WARNING The maximum safe voltage between picoammeter LO and chassis ground common mode voltage is 505V peak The Model 6487 does not internally limit the LO to chassi...

Page 41: ...est fixture is shown in Figure 2 6 This test fixture will accommodate a variety of connection requirements Model 8009 resistivity test fixture This test fixture allows volume resistivity in the range...

Page 42: ...METER SOURCE LID INTERLOCK TRIAX XXX MAX HI LO MAX INPUT XXXXV Model 8009 6517 ILC 3 Safety Interlock Cable 7078 TRX 3 Triax Cable 8607 Banana Plug Cables Model 6487 TRIAX 120 LINE RATING 50 60Hz 50...

Page 43: ...tor as shown When the switch is open the interlock is asserted and the voltage source cannot be placed in operate on the 50V or 500V voltage source ranges and option ally for the 10V range WARNING If...

Page 44: ...ut signal is not corrected during calibration Gain errors of up to 2 5 may appear at this output depending on range The output impedance is 100 To minimize the effects of loading the input impedance o...

Page 45: ...nual For comprehensive information on all measurement considerations refer to the Low Level Measurements handbook which is available from Keithley Instruments Test Lead 120 LINE RATING 50 60Hz 50 VA M...

Page 46: ...n a cable by friction between a conductor and the surrounding insulator i e bending a triax cable Piezoelectric and stored charge effects Currents generated by mechanical stress on certain insulating...

Page 47: ...2 12 Connections Model 6487 User s Manual...

Page 48: ...rformance considerations Covers warm up period voltage offset correction auto zero zero check and zero correct Current measurements Provides a basic procedure to measure current Ohms measurements Cove...

Page 49: ...pecifications Appendix A Voltage source The basic voltage source output capabilities of the Model 6487 are summarized in Table 3 2 Accuracy specifications are shown in Appendix A Table 3 1 Basic curre...

Page 50: ...ically measures internal voltages corresponding to offsets zero and amplifier gains a process known as autozeroing With autozero disabled measurement speed increases up to three times but measurement...

Page 51: ...o check enabled NOTES With regard to the zero correct feature The Model 6487 will remain zero corrected even if it is upranged If down ranged re zero the instrument The Model 6487 does not have to be...

Page 52: ...values may cause damage to the instrument that is not covered by the warranty Perform the following steps to measure current Step 1 Select current function Press the I key to make sure the current fu...

Page 53: ...h as with the ground link connection on the rear panel of the 6487 See Ground loops page B 2 Fundamental information on making connections to the picoammeter input is provided in Section 2 Step 6 Disa...

Page 54: ...rigger reading to be used as zero correction SYST ZCOR ACQ Use last reading taken as zero correct value SYST ZCOR ON Perform zero correction RANG AUTO ON Enable auto range SYST ZCH OFF Disable zero ch...

Page 55: ...ting voltage mode Procedure WARNING Always turn off the Model 6487 s voltage source before changing volt age source connections to avoid a possible shock hazard Perform the following steps to measure...

Page 56: ...nd using 18 AWG or larger wire Step 5 Select ohms function Press the I key to make sure the ohms function is selected Step 6 Turn on voltage source Press the OPER key to turn on the voltage source out...

Page 57: ...or 500 Set output voltage 505V to 505V Set current limit 25 A 250 A 2 5mA or 25mA Turn voltage source output ON or OFF Trigger and return reading s Zero correct and zero check commands not included S...

Page 58: ...ct DC for normal operation See Section 6 for details on sweeps After the mode is selected the display shows a full resolution value of the voltage source with the left most position highlighted for ed...

Page 59: ...ht blinks In contrast the safety interlock will cause the voltage source to go into a high impedance state instead of 0V output and the source will stay in the high impedance state until the operate s...

Page 60: ...RANG 10 Select 10V source range SOUR VOLT 5 Set voltage source output to 5 SOUR VOLT ILIM 2 5e 3 Set current limit to 2 5mA SOUR VOLT STAT ON Put voltage source in operate Table 3 7 SCPI commands volt...

Page 61: ...3 14 Measurements and Sourcing Voltage Model 6487 User s Manual...

Page 62: ...e SCPI commands for remote operation Rate Provides details on reading rate selection Includes the SCPI commands for remote operation Damping Provides details on damping rate selection Includes the SCP...

Page 63: ...plied signal Up ranging occurs at 105 of range while down ranging occurs at the range value The AUTO key toggles the instrument between manual ranging and autoranging The AUTO annunciator turns on whe...

Page 64: ...easure ment ranges To set display resolution press and release the DIGITS key until the desired number of digits is displayed NOTE The voltage source value will not be displayed in the 6 digit display...

Page 65: ...n of both Enabling damping analog filtering will reduce noise caused by high capacitance for current measurements However damping will also slow down the response of the measurement To enable or disab...

Page 66: ...where R is the selected rank 1 to 5 Note that the median filter throws out the oldest of the ranked values and it is especially useful for noise characterized by unwanted spikes Digital filter Digital...

Page 67: ...essing FILT The FILT annunciator will show when the filter is on SCPI commands filters Programming example The following command sequence configures and enables both filters Median Filter MED RANK 5 S...

Page 68: ...tive Explains how to null an offset or establish a baseline value Includes the SCPI commands for remote operation mX b m X b reciprocal and Logarithmic Covers these three basic math operations and inc...

Page 69: ...ue To use the present reading first disable zero check display the reading then press REL The REL annunciator will turn on and subsequent readings will be the difference between the actual input and t...

Page 70: ...ally according to the following calculations Y mX b Y m X b where X is the normal display reading m and b are user entered constants for scale factor and offset Y is the displayed result NOTE Changing...

Page 71: ...he result RST Restore RST defaults CALC FORM MXB Select mX b calculation CALC KMAT MMF 2e 3 Set scale factor M to 2e 3 CALC KMAT MBF 5e 4 Set offset B to 5e 4 CALC STAT ON Enable calculation SYST ZCH...

Page 72: ...6 BufferandSweeps Buffer operations Explains how to store and recall readings including buffer statistics Voltage sweeps Discusses how to generate sweeps using the voltage source...

Page 73: ...eadings to store 1 3000 and press ENTER Press the STORE key to start data storage The asterisk annunciator turns on to indicate that the data storage operation is active To abort storage while active...

Page 74: ...he mean of the buffer readings Mean is calculated as follows Where Xi is a stored reading n is the number of stored readings The STD DEV value is the standard deviation of the buffered readings Standa...

Page 75: ...ONT NEXT Start storing readings SYST ZCH OFF Turn off zero check INIT Trigger readings TRAC DATA Request all stored readings Acquire Mean Statistic for Buffer Readings CALC3 FORM MEAN Select mean stat...

Page 76: ...be stored in the buffer for later recall see Recall page 6 2 To abort a sweep in progress press the EXIT key SCPI programming sweeps NOTE When programming sweeps via remote the arm count may have to...

Page 77: ...lts SOUR VOLT SWE STAR 1 Start voltage 1V SOUR VOLT SWE STOP 10 Stop voltage 10V SOUR VOLT SWE STEP 1 Step voltage 1V SOUR VOLT SWE DEL 0 1 0 1s delay ARM COUN INF Reset arm count FORM ELEM READ VSO S...

Page 78: ...ng and configuring an interface Explains how to select and configure an interface GPIB or RS 232 Remote commands Lists the following types of bus commands general bus commands common commands signal o...

Page 79: ...avoid address conflicts Use the SCPI language setting for most applications See the Model 6487 Reference Manual for information on the DCC and 488 1 programming languages RS 232 interface To configur...

Page 80: ...ice request LOCAL key The LOCAL key cancels the remote state and restores local operation of the instrument Pressing the LOCAL key also turns off the REM indicator and returns the display to nor mal i...

Page 81: ...ummarized in Table 7 2 Table 7 1 General bus commands Command Effect on Model 6487 REN Goes into remote when next addressed to listen IFC Reset interface all devices go into talker and listener idle s...

Page 82: ...ding selected device operations have been completed OPT Option query Returns model number of any installed options RCL NRf Recall command Returns Model 6487 to the user saved setup RST Reset command R...

Page 83: ...n optional command word that does not need to be included in the program message Common commands and SCPI commands are not case sensitive You can use upper or lower case and any case combination A SCP...

Page 84: ...t a parameter name from a listed group NRf Numeric representation format A number that can be expressed as an integer e g 8 a real number e g 23 6 or an exponent 2 3E6 NDN Non decimal numeric A non de...

Page 85: ...7 8 Remote Operation and Commands Model 6487 User s Manual...

Page 86: ...A Specifications...

Page 87: ...EE 488 1 3 Measured from trigger in to meter complete TEMPERATURE COEFFICIENT 0 18 C 28 50 C For each C add 0 1 rdg offset to accuracy spec INPUT VOLTAGE BURDEN 200 V on all ranges except 1mV on 20mA...

Page 88: ...B GeneralMeasurement Considerations...

Page 89: ...nter small resistances either in the wires or at the connecting points This small resistance results in voltage drops that can affect the measurement Even if the ground loop currents are small magneti...

Page 90: ...hese cables are specially designed to minimize charge generation and use graphite to reduce friction The Keithley Model 237 and 7078 cables are low noise Use the shortest cables possible and secure th...

Page 91: ...Some components such as semiconductor junctions and MOS capacitors on semiconduc tor wafers are excellent light detectors Consequently these components must be tested in a light free environment While...

Page 92: ...s the amount of electrostatic interference seen in the measurement Magnetic fields A magnetic field passing through a loop in a test circuit will generate a magnetic EMF voltage that is proportional t...

Page 93: ...ds will often reduce EMI to an acceptable level In extreme cases a specially constructed screen room may be required to sufficiently attenuate the troublesome signal External filtering of the input si...

Page 94: ...C ExamplePrograms...

Page 95: ...000 NPLC 01 Set integration rate to 01 PLC RANG 002 Use 2mA range SYST ZCH OFF Turn zero check off SYST AZER STAT OFF Turn auto zero off DISP ENAB OFF Turn display off CLS Clear status model TRAC POIN...

Page 96: ...LANG 488 1 then press ENTER See reference manual for details RST Return 6487 to RST defaults FORM ELEM READ Return readings only FORM BORD SWAP Set for swapped byte order FORM DATA SRE Return single p...

Page 97: ...r count to 1500 NPLC 01 Set integration rate to 01 PLC RANG 002 Use 2mA range SYST ZCH OFF Turn zero check off CLS Clear status model TRAC POIN 3000 Set buffer size to 3000 TRAC CLE Clear buffer TRAC...

Page 98: ...gital 1 12 4 5 filter 4 5 filter control 4 6 DIGITS 1 8 Digits 4 3 DISP 1 8 Display 1 9 1 12 E Electrochemical effects B 4 Electromagnetic Interference EMI B 5 Electrostatic interference B 4 engineeri...

Page 99: ...rigger link adapter 1 5 Model 8503 DIN to BNC trigger cable 1 5 Models 7007 1 and 7007 2 shielded GPIB cables 1 5 Models 8501 1 and 8501 2 trigger link cables 1 5 MON 1 9 mX 5 3 mX b m X b reciprocal...

Page 100: ...Setting and controlling relative 5 2 SETUP 1 8 Shielding 2 6 Signal 7 5 SLOW 1 9 Sourcing 3 1 3 12 Special keys and power switch 1 8 Specifications A 1 SRQ 1 9 STAT 1 9 statistics 6 3 Status 1 12 STD...

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Page 102: ...Unstable Overload Will not read applied input Calibration only Certificate of calibration required Data required attach any additional sheets as necessary Show a block diagram of your measurement inc...

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Page 105: ...0 11 77 26 GERMANY Landsberger Strasse 65 82110 Germering 089 84 93 07 40 Fax 089 84 93 07 34 GREAT BRITAIN Unit 2 Commerce Park Brunel Road Theale Berkshire RG7 4AB 0118 929 7500 Fax 0118 929 7519 IN...