Keithley 617 User Manual Download

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Established 1981

Summary of Contents for 617

Page 1: ...Model 617 Programmable Electrometer Instruction Manual Contains Operating and Servicing Information Advanced Test Equipment Rentals www atecorp com 800 404 ATEC 2832 Established 1981 ...

Page 2: ...not apply to defects resulting from product modification without Keithley s express written consent or misuse of any product or part This warranty also does not apply to fuses software non rechargeable batteries damage from battery leakage or problems arising from normal wear or failure to follow instructions THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING ANY IMPLI...

Page 3: ...Model 617 Programmable Electrometer Instruction Manual 0 1984 Keithley Instruments Inc Test Instrumentation Group All rights reserved Cleveland Ohio U S A Document Number 617 901 01 Rev C ...

Page 4: ...SPECIFICATIONS ...

Page 5: ...cators TiltBan Front Panel Programs IEEE 488 Address Exponent Mode Alpha or Numeric Calibration Rear Panel Familiarization Connectors and Terminals V RGUARDSwitch LineFuse Basic Measurement Techniques Warm Up Period Input Connections Making Voltage Measurements Guarded Operation Making Current Measurements Making Charge Measurements Resistance Measurements Using the Ohms Function As A Current Sour...

Page 6: ...ion 3 l BusDescription 3 l IEEE 488BUSLINES 3 2 DataLines 3 2 BusManagementLines r 3 2 HandshakeLines 3 2 BusCommands 3 3 UniIineCommands 3 3 UniversalCommands 3 4 AddressedCommands 3 4 Unaddressedcommands 3 5 Device DependentCommands 3 5 CommandCodes 3 5 CommandSequences 3 5 AddressedCommandSequence 3 5 UniversalCommandSequence 3 7 Device DependentCommandSequence 3 7 Hardwareconsiderations 3 7 Ty...

Page 7: ...r Bus Data Transmission Times SECTION 4 APPLICATIONS Introduction Insulation Resistance Measurements HighImpedanceVoItmeter Low Level Leakage Current Measurements DiodeCharacterization CapacitorLeakageMeasurements CapacitanceMeasurement Voltage Coefficients of High Megohm Resistors Static Charge Detection Using the Model 617 with External Voltage Sources SECTION 5 PERFORMANCE VERIFICATION Introduc...

Page 8: ...ION 7 MAINTENANCE 6 l 6 1 6 l 6 3 6 3 6 3 6 6 6 7 6 7 6 7 6 8 6 9 6 9 6 11 6 11 6 11 6 u 6 11 6 12 6 12 6 13 6 14 Introduction LineVoltageSelection FuseReplacement Lim Fuse COMFuse Calibration Recommended Calibration Equipment EnvironmentalConditions WarmUpPeriod CalibrationJumper Front Panel Calibration IEEE 488 Bus Calibration Calibration Sequence InputOffsetAdjustment InputCurrentAdjustment Pem...

Page 9: ...7 DigitalCircuitry 7 17 Display Board 7 17 VoltageSource 7 17 InputStageBalancingProcedure 7 17 Handling and Cleaning Precautions 7 18 SECTION 8 REPLACEABLE PARTS Introduction Electrical Parts Lists Mechanical Parts Ordering Information Factory Service Component Layout Drawings and Schematic Diagrams 8 l 8 l 8 l 8 l 8 l 8 l ...

Page 10: ...ations Unguarded Circuit GuardedCircuit Guarded Input Connections CurrentMeasurements Voltage Burden Considerations Coulombs Connections Resistance Measurement Connections Voltage Source Connections V l Resistance Measurement Connections Typical 2V Analog Output Connections Typical Preamp Out Connections Electrometer Input Circuitry AmpsMode Shielded Fixture Construction Transdiode Logarithmic Cur...

Page 11: ...2 b 13 b 14 b 15 6 16 Overall Block Diagram Basic Configuration Electrometer Preamplifier Electrometer Preamplifier Configuration Simplified Schematic of Input Stage GainStage Output Stage Configuration Volts and Ohms Output Stage Configuration Amps and Coulombs Ohms Voltage Source Simplified Schematic Zero Check Configuration Volts and Ohms Zero Check Configuration Amps and Coulombs Simplified Sc...

Page 12: ... Drawing g 2 Mother Board Component Location Drawing 8 3 Display Board Component Location Drawing 8 4 Electrometer Board Schematic Diagram 8 5 Mother Board Schematic Diagram 8 6 Display Board Schematic Diagram 8 11 g 13 8 17 8 19 8 21 8 27 VW ...

Page 13: ...pendent Command Sequence IEEE Contact Designations BASIC Statements Necessary to Send Bus Commands Model 617Interface Function Codes IEEE Command Groups General Bus Commands and Associated BASIC Statements Default Conditions Device Dependent Command Summary Range Command Summary SRQ M Command Parameters Bus Hold Off Times Typical Bus Times For Various Functions and Trigger Modes 3 4 3 5 3 7 3 7 3 ...

Page 14: ...icSensitiveDevices 7 11 Recommended Troubleshooting Equipment 7 14 DiagnosticProgramPhase 7 15 PowerSupplyChecks 7 15 Relayconfiguration 7 16 Ranging Amplifier Gains 7 17 A DConverterChecks 7 18 Preamplifierchecks 7 19 RangingAmplifierChecks 7 1 9 DigitalCircuitryChecks 7 20 DisplayBoardChecks 7 20 VoltageSourceChecks 7 21 InputStageBalancing 7 21 MotherBoard PartsList 8 2 DisplayBoard PartsList 8...

Page 15: ... ANALOG OUTPUT to earth ground when floating input Inspect the test leads for possible wear cracks or breaks before each use If any defects are found replace with test leads that have the same measure of safety as those supplied with the instrument For optimum safety do not touch the test leads or the instrument while power is applied to the circuit under test Turn the power off and discharge all ...

Page 16: ...electable driven cable guard is in cluded to optimize speed l Standard IEEE 488 Interface The interface allows full bus programmable operation of the Model 617 l Analog Outputs Both preamp and 2V full range analog outputs are included on the rear panel l 100 Point Data Store An internal buffer that can store up to 100 readings is accessible from either the front panel or over the IEEE 488 bus l Mi...

Page 17: ...strument carefully unpack all items from the shipping carton and check for any obvious signs of physical damage that might have oc curred during shipment Report any damage to the shipping agent at once Retain the original packing material in case reshipment becomes necessary The following items aw included with every Model 617 ship ment Model 617 Programmable Electrometer Model 617 Instruction Man...

Page 18: ... 6012 Triax to UHF Adapter The Model 6012 allows the Model 617 to be used with accessories having UHF type co nectors Model 6lOlA Shielded Test Lead The Model 610lA is a straight through probe and shielded lead equipped with 0 8m 3O of shielded low noise cable terminated by a Teflon insulated UHF connector The Model 6012 must be used to adapt the Model 6101A to the Model 617 triaxial input Model 6...

Page 19: ...del 7023 is a chassis mount connector that mates with the Models 6011 and 7024 triaxial cables Model 7024 Triaxial Cables The Model 7024 cables are similar units with male triaxial connectors on each end The Model 7024 l is 0 3m 1 ft in length while the Models 7024 3 and 7024 10 are 0 9m 3 ft and 3 0m 10 ft long respectively These cables may be used to connect the Model 617 signal input to other e...

Page 20: ...in instrument damage If necessary the line voltage may be changed as decribed in Section 7 2 Turn on the power by pressing in the front panel POWER switch The switch will be at the inner most position when the instrument is turned on 3 The instrument will power up in the volts function in the autorange mode aqd with zero check enabled as indicated by the associated front panel LEDs All other LEDs ...

Page 21: ...itch SHIFT The SHIFT button adds a secondary function to some of the other front panel controls including VOLTS TRIG OHMS RECALL and PROGRAM SELECT Note that the shift function is entered by pressing SHIFT before the second button rather than pressing the two simultaneously ELECTROMETER The ELECTROMETER buttons control the measuring functions selection of instrument ranges and such items as zero c...

Page 22: ... suppress that value would then be subtracted from subsequent readings Once suppress is en abled the value is scaled when the range is changed Suppress may be disabled by pressing the SUPRESS button a second time and is cancelled if the function is changed TRIG The TRIG button allows you to enter the one shot trigger mode and trigger single readings from the front panel To enter the one shot mode ...

Page 23: ...he display represents an electrometer reading When the SOURCE LED is illuminated the voltage source value is being displayed A data store reading is displayed when the DATA LED is turned on Normally the display will be the the meter mode but the DISPLAY and RECALL buttons will switch the display to the source and data modes respectively STATUS Indicators These three indicators apply to opera tion ...

Page 24: ...elect the exponent program scroll through theprogram menu until the following message is displayed dISI Use either of the V SOURCE ADJUST buttons to set theex ponent to the desired mode In the numeric mode the display might show dISP 3 dISI m Once the desired exponent mode is selected press SHIFT then SELECT EXIT to return to normal operation or simply PRO GRAM SELECT if a change was made 2 5 3 Ca...

Page 25: ...t or charge The PREAMP OUT has a maximum output value of k3C0V and uses a standard s way binding post WARNING Hazardous voltage may be present at the PREAMP OUT depending on the input signal 2 6 icientific Uotation 10 77 A 10 w lo GA lo 3v 103Q lO l low 1012sl 101522 f N rv 1 i anocoulombr licroamperes Millivolts Kilohms Megohms Gigohms Teraohms Petaohms COM Terminal The COM terminal is a 5way bin...

Page 26: ... 617 has provisions for connecting a guard to the inner shield of the input cable Guarding is useful in the volts and ohms modes to speed up response time and minimize the effects of leakage resistance Note that guarded operation is not recommended in amps or coulombs The V Q GUARD switch allows easy selection of the guarded mode of cpera ticn See paragraph 2 7 4 for more information on guarded op...

Page 27: ...e Model 617 can be used to measure voltages in the range of lOpV to 2COV In principle the instrument operates much like an ordinary DMM but its special characteristics allow it to make measurements in cases where an ordinary DMM would be unable to perform well In particular the very high input resistance of 2oOTSl 2 X 1OW allows it to accurately measure voltage sources with high internal resistanc...

Page 28: ...o loading can be calculated as follows 100 RS ERROR Rs RIN Thus to keep the error under 0 1 the input resistance must be about 1000 times the value of the source resistance R At very high resistance levels the very large time contants created by even a minimal amount of capacitance can slow down response time considerably For example measuring a wurce with an internal resistance of 1OOGQ would res...

Page 29: ...mes the source resistance value Guarding the circuit miminizes these effects by driving the shield at signal potential as shown in Figure 2 7 Here a uni ty gain amplifier with a high input impedance and low output impedance is used The input of the amplifier is connected to the signal while the output is used to drive the shield Since the amplifier has unity gain the potential across ZLis essen ti...

Page 30: ...d zero check disabled allow the reading to settle until the in strument is within specifications NOTE Safe operation and good measurement practice dictates the use of an external resistor when necessary to limit currents to less than 3011 4 To measure current with the Model 617 use the following procedure I Turn on the power and allow the instrument to warm up for at least two hours to obtain rate...

Page 31: ...ance RS is shown connected to the input of a picoammeter The voltage burden is represented by a con stant voltage source at the input as Em If En l were zero the current as seen by the meter would simply be Es Rs However if EIN has a non zero value the current now becomes Es 6 IA RS Additional considerations include source resistance and capacitance as discussed in paragraph 2 14 00 cl _ SAFETY SH...

Page 32: ...ow as 1OfC 10 W and measure as high as 20nC 20 X 10 K When the instrument is placed in one of the coulombs ranges an accurately known capacitor is placed in the feedback loop of the amplifier so that the voltage developed is proportional to the integral of the input current in accordance with the formula V j idt The voltage is scaled and displayed as charge Figure 2 10 Voltage Burden Consideration...

Page 33: ...RRECT button 4 Select the desired range or use autoranging if desired 5 Disable zero check A small amount of zero check hop sudden change in the reading may be observed when zero check is disabled If desired enable suppress to null out any zero check hop which typically will be in the lo 25 count range 6 Connect the Model 6011 cable to the INPUT jack Connect the other end of the cable to the circu...

Page 34: ...t least R lOOOV in ohms where V is the voltage across the capacitor or the compliance of the cur rent being integrated 2 7 7 Resistance Measurements discussed in paragraph 2 8 uses the built in voltage source With the constant current method discussed here the instru ment can resolve resistances as low as O la and measure as high as 2COGR To measure resistance with the Model 617 use the following ...

Page 35: ...d black alli gator clips to the circuit under test Select the resistance range in accordance with the desired current see Table 2 4 Note that current flows from input high through input low The test voltage is less than 2V for all ranges 2GQ and less except when an overload occurs in which case the compliance is 3OQv 6011 CABLE I Id oo l 0 0 MDDEL 617 INPUT AMPLIFIER I I 1 L I I MEASURE RESISTANCE...

Page 36: ...urce output on The LED adjacent to this button will illuminate when the output is turned on The OPERATE LED will flash if the 2nd cur rent limit is exceeded WARNING Dangerous voltage may be present on the sourca terminals when the output is enabled 5 To turn the source output off simply press the OPERATE button a second time The source output will then be pro grammed to OO OLW MODEL617 I I n 0 00 ...

Page 37: ...e meter mode 8 Disable zero check The meter will now display the current being sourced through the resistor under test by the voltage sowce To measure from a baseline current such as fixture leakage enable suppress while in amps 9 To display the resistance being measured press SHIFT and then OHMS in that order The V I light will turn on indi cating that the V I ohms mode is enabled If a displayed ...

Page 38: ... on its output With the instrument in the amps mode enable suppress to null the leakage current Turn off the source connect the resistor and re enable the voltage source Place the instrument in the V I ohms mode and pro ceed with the measurement High megohm resistors are somewhat curious devices often exhibiting characteristics somewhere between those of an in sulator and a normal re tor Because o...

Page 39: ...ppm Table 2 5 Typical 2V Analog Output Values ZV Analog OutputValue 1 04v 1 65V 1 4v 0 35v 1 75v 0 95v 1 25V 1 9v 00 n o cl MODEL 617 RF 2MR IX101 200kR X1 20kR 1X0 11 2kR lXO 01 I Table 2 6 Full Range PREAMP OUT Values _ I 200mV 200mV 2 v 2v Amps Ohms 20 v 200 v 2 4 2nA 2 ln 2mA 20pA 20nA 20 20mA 200pA 200nA 2OOfi 2 k0 20kD 2GQ 20GQ 20 v 200 v 200mV 2v 20 v 200mV 2v 20 v Coulombs 1 200GQ 1 200 v ...

Page 40: ...utput resistance appears between Input Low and Analog Output Low to keep the resistor out of the loop when using external feedback elements To keep loading errors under 0 1 the device con netted to the PREAMP OUT should have a minimum input impedance of 1OOkQ damage the instrument 0 0 00 Jf MODEL 1683 TEST LEAD KIT MEASURING DEVICE MODEL 617 lOoR 77 GND S VOLTS Rt 1000 t 1 r a 6 COULOMBS EWIVALENT...

Page 41: ... greater than 106 Note that the input impedance is ZIN lOM0 II2 when zero check is enabled 3 The voltage at the PREAMI OUT terrrtinal is given by the formula V IRFB where Rm is thevalue of the feedback resistance 4 Any feedback elements should be housed in a suitable shielded enclosure Insulators connected to Input HI should be made of Teflon or other high quality insulating material and should be...

Page 42: ... a 150mV output the display will show external feedback mode 150 00 m 1 Connect the feedback element between the PREAMP OUT 1 Connect the feedback element between th terminal and the Input High terminal terminal and the Input v4 h in 4 External feedback may be temporarily digitally calibrated 2 Place the instrument in LX CXKJXWZ x 2 Place the instrument in the external feedback mode by as outlined...

Page 43: ...ed and the maxi mum current level expected Compensation at maximum cur rent is required because the dynamic impedance will be minimum at this point It should be noted that the response speed at lower currents will be compromised due to the in creasing dynamic impedance which is given by the following formula dV 2 KT qI 0 026 I 25 C d1 Using the above transistors a minimum RC time constant of lC se...

Page 44: ...s purpose Limitations on the magnitude of the feedback curr ent require that the value of RFB be greater than loan NOTE The circuit topology of Figure 2 19 works for positive input currents only For bipolar input signals an external offset bias must be applied or use a PNP at QL Note that external feedback can be temporarily calibrated i12 using the calibration program with the calibration jumper ...

Page 45: ...ote that the specifications listed for the instrument at the front of this manual assume that the instrument has been zeroed Use the following procedure to zero the instru ment Note that the zero should be corrected on the range to be used or on the lowest range of the function being used changed 2 1003 mAI lOOk II 1OOOpFCd 1OOMOII 22OpF InA lOOGO n 5PF IDA i lOOk II lOOO F ALL kn 2MQ IOOMR n 22pF...

Page 46: ...nput voltage of 1OOmV or more would overrange the instrument even though input vol tages up to 199 99mV are normally within the capabilities of the 2OOmV range If the instrument is in the autorange mode it will move up range if necessary 2 Setting the range lower than the suppressed value will overrange the display the instrument will display the OL message under these conditions 3 To store a new ...

Page 47: ...s as n lO 7 To continue recalling readings use the RECALL button to scroll the data pointer Scrolling becomes more rapid if the RECALL button is held in Release the button when the desired data point is displayed 8 The recall mode can be cancelled simply by pressing SHIFT RECALL The instrument will then return to the normal display mode As long as data store is not disabled and then w enabled read...

Page 48: ...l Trigger Pulse Specifications To use the external triggering proceed as follows 1 Connect the external trigger source to the rear panel BNC EXTERNAL TRIGGER INPUT connector The shield outer part of the connector is connected to digital com mon Since an internal pull up resistor is used a mechanical switch may be used Note however that de bouncing circuitry will probably be required to avoid im pr...

Page 49: ... completes the reading it will trigger the Model 705 to go to the next channel The process repeats until all programmed channels have been scanned 2 13 3 Triggering Example 2 14 MEASUREMENT CONSIDERATIONS As an example of using both the external trigger input and the meter complete output assume that the Model 617 is to be used in conjunction with a Keithley Model 705 Scanner to allow the Model 61...

Page 50: ...14 2 Electrostatic Interference Electrostatic interference occurs when an electrically charged object is brought near an uncharged object thus inducing a charge on the previously uncharged object Usually effects of such electrostatic action are not noticable because low im pedance levels allow the induced charge to dissipate quickly However the high impedance levels of many Model 617 Elec trometer...

Page 51: ...e seen as an unusually large offset or in the case of impulse sources sudden erratic variations in the displayed reading RF1 can be minimized by taking one or more of several precautions when operating the Model 617 in such en vironments The most obvious method is to keep the instru ment and experiment as far away from the RF1 source as possible Shielding the instrument experiment and test leads w...

Page 52: ... of the charging of GIN the electrometer follows the exponential curve shown in Figure 2 288 At the end of one time constant R IN the voltage will reach approximately 63 of its final value At the end of two time constants 2R5C the voltage will reach about 86 of its final value and so on Generally at least five time constants should be allowed for better than 1 accuracy The amount of time that must...

Page 53: ...and Source Capacitance Effects Table 2 9 Minimum Recommended Source Resis tance Values in Amps Minimum Source RangeI All pA 1 Resistance lOOGil 1OOMQ 100kQ All mA 100 n Output Enoise RF Input En X 1 Rs As shown in Table 2 9 a minimum value of source resistance is recommended for each AMPS range The reason for this Thus it is clear that as long as Rs RF Output E ise In can be understood by examinin...

Page 54: ...s becomes larger the noise gain becomes larger An application where Cs may be greater than 10 COOpF is leakage measurement of capacitors In this case Input E must include the effects of the voltage source Es used to bias the capacitor any noise in the source voltage will increase the input noise When measuring leakage currents on capacitors larger than lO OOOpF stability and noise performance can ...

Page 55: ...dditional information necessary to use the Model 617 over the IEEE 488 bus is located in the remaining para graphs 3 2 BUS DESCRIPTION The IEEE 488 bus which is also frequently referred to as the GPIB General Purpose Interface Bus was designed as a parallel transfer medium to optimize data transfer without us ing an excessive number of bus lines In keeping with this goal the bus has only eight dat...

Page 56: ...aring of instruments from the bus OR the primary address value with 40 With the present example the talk address derived from a primary address of REN Remote Enable The REN line is used to place instru 27 decimal would be 5B SB lB t 40 ment on the bus in the remote mode EOI End or Identify The EOI line is usually used to mark The IEEE 488 standards also include another addressing mode the end of a...

Page 57: ... goes high when the slowest device is ready and the bus is set to repeat the preocess with the next data byte The sequence just described is used to transfer data talk and listen addresses as well as multiline commands The state of the ATN line determines whether the data bus contains data addresses or commands as described in the following paragraph 3 4 BUS COMMANDS While hardware aspects of the ...

Page 58: ...vice Clear The SDC command performs essentially the same function as the DCL command except that only the addressed device responds Generally in struments return to their power up default conditions when responding to the SDC command GTL Go To Local The GTL command is used to remove instruments from the remote mode With some instruments GTL also unlocks front panel controls if they were previously...

Page 59: ...II data This section briefly explains the code groups which are summarized in Figure 3 3 hmmand GIL SDC GET LLO DCL SPE SPD LAG TAG UNL UNT 1 Hex Value 01 04 08 11 14 18 19 20 3F 40 5F 3F 5F 3 6 COMMAND SEQUENCES Addressed Command Group ACG Addressed commands _ _I Decimal Value 1 4 8 17 20 24 25 32 63 64 95 63 95 an co esp0n 1ng ASCII codes are listed in cohxnns WA and O B Universal Command Group ...

Page 60: ...L c x I x c x I x 3 6 ...

Page 61: ...es primary address 27 3 7 HARDWARE CONSIDERATIONS Before the Model 617 can be operated over the IEEE 466 bus it must first be connected to the bus with a suitable cable Also the primary address must be programmed to the correct value as described in the following paragraphs 3 7 1 Typical Cohtrolled Systems System configurations are many and varied and will depend on the application To obtain as mu...

Page 62: ...h end These connectors are designed to be stacked to allow a number of parallel connections on one instrument NOTE To avoid possible damage it is recommended that you stack no more than three connectors on any one instrument Connect the Model 617 to the cable as follows 1 Line up the connector on the cable with the connector on the rear panel of the instrument See Figure 3 7 for connec tor locatio...

Page 63: ... controllers are also given a primary ad dress so you must be careful not to use that address either Most frequently controller addresses are set to 0 or 21 but you should consult the controller s instruction manual for details Whatever primary address you choose you must make certain that it corresponds with the value specified as part of the controller s programming language To checkthepresent p...

Page 64: ...iffering capabilities In this section we will discuss programming languages for two typical controllers the HP 85 and the IBM PC interfaced to the bus through a Keithley Model 8573 IEEE 488 interface In addition interface functions codes that define Model 617 capabilities will be discussed 3 8 1 Controller Handler Software Before a specific controller can be used over the IEEE 488 bus it must have...

Page 65: ...sing the procedure below Note that thebinary handler file called GPIB COM and the system configuration file called CONFIGSYS must be present on the DOS boot disk as described in the Model 8573 Instruction Manual 1 Boot up your system in theusualmanner and enter BASICA 2 Place the Model i573 software disk into the default drive and load the program called DECL BAS Modify the program by changing the...

Page 66: ...on defines the ability of the Model 617 to be cleared initialized DT Device Trigger Function The ability for the Model 617 to have its readings triggered is provided by theDT function C Controller Function The Model 617 does not have con troller capabilities TE Extended Talker Function The Model 617 does not have extended talker capabilities LE Extended Listener Function The Model 617 does not hav...

Page 67: ...st perform the following sequence 1 Set theREN line true 2 Address the Model 617 to listen HP 85 Programming Example This sequence is automatically performed by the HP 85 when the following is typed into the keyboard REMOTE 727 END LINE After the END LINE key is pressed the Model 617 will be in the remote mode as indicated by the REMOTE light If not check to see that theinstrument is set to the pr...

Page 68: ...tatement REMOTE 7 END LINE At this point the REMOTE and TALK lights should be on LOCAL LOCKOUT 7 END LINE The IFC command can be sent by typing in the following statement into the HP 85 After the second statement is entered the instrument s front ABORT10 7 END LINE After the END LINE key is pressed the REMOTE and TALK lights will turn off indicating that the instrument has gone in to the talker id...

Page 69: ...2 Place the DCL command byte on the data bus controls Now enter the following statement into the HP 85 keyboard CLEAR 7 END LINE When the END LINE key is pressed the instrument returns to the default conditions listed in Table 3 10 Model 8573Programming Example Placethe unit in the amps function and cancel autorange with the front panel controls Now enter the following statement into the IBM compu...

Page 70: ...sure the instrument is in the remote and correct trigger modes for purposes of this demonstration V l CALL IBSRE BRDO V return CMD T3X CALL IBWRT M617 CMD retum Now send GET to the instrument with the following state ment CALL IBTRG M617 return When the return key is pressed the instrument will process a single reading 3 9 8 Serial Polling SPE SPD The serial polling sequence is used to obtain the ...

Page 71: ...front panel error messages and generate an SRQ if programmed to do so Commands that affect the electrometer section F R C Z N T and A will trigger a reading when the command is ex ecuted These bus commands affect the Model 617 much like the front panel controls Note that commands are not necessarily executed in the order received instead they will be executed in the same order as they appear in th...

Page 72: ...r com mands were sent Note that the instrument remains in the listener active state after the command is transmitted Modal 8573 Programming Example Enter the following statements into the IBM computer V l CALL IBSRE BRDO V return CMD X CALL IBWRT M617 CMD return When the retmn key is pressed the second time the X character is transmitted to the instrument although no mode changes occur because no ...

Page 73: ...200 kQ R12 Cancel autoranging forall functions ero Check co ZeroCheckOff 3 10 4 Cl ZeroCheckOn ero correct zo ZeroCorrect Disabled 3 10 4 Zl ZeroCorrect Enabled laseline Suppression NO Suppression Disabled 3 10 5 Nl Suppression Enabled display Mode DO Electrometer 3 10 6 Dl Voltage Source leading Mode BO Electrometer 3 10 7 El Buffer Reading 82 Maximum Reading 83 Minimum Reading 84 Voltage Source ...

Page 74: ...nator Send Status Format 617 FRRCZNTOBGDQMMKYY Error Conditions DataConditions Paragraph 3 10 13 3 10 14 3 10 15 3 10 16 3 10 17 3 10 18 HP 85 Programming Example Make sure the instrument is in the autorange mode and then enter the following statements into the HP 85 The range command gives the user control over thesensitivi ty of the instrument This command and its options perform REMOTE 727 END ...

Page 75: ...o check by sending ClX 2 Zero correct the instrument by sending ZlX 3 Disable zero check by sending COX Readings can then be taken in the usual manner HP 85 Programming Example Enterthefollowing lines into theHP 85 computer REMOTE 727 END LINE OUTPUT 727 ClXZlXCOX END LINE When END LINE is pressed the second time the instrument is first placed in zero check the unit is zero corrected and the zeroc...

Page 76: ...e same function as the front ms essentially the same function as the front The two parameters associated with the display mode com panel DISPLAY button The two display command AY button The two display command parameters are 4 Enable baseline suppression by sending NlX over the bus The baseline will be stored when the command is executed 5 Disconnect the baseline signal from the instrument and con...

Page 77: ...ENTER 727 A END LINE DISP A END LINE The second command above changes the reading mode to ac cess the voltage source while the third and fourth statements acquire the reading and display it on the CRT Model 8573 Programming Example To display the voltage source value on the computer CRT enter the follow ing program statements into the IBM computer V l CALL IBSRE BRDO V return CMD B4X CALL IBWRT M6...

Page 78: ... program will enable data store line 30 wait for memory to fill lines 40 and 501 turn on the data store output line 60 and then request and display all loo readings lines 70 100 Model 8573 Programming Example To demonstrate data store operation load the modified DECL BAS file and enter the program lines below PROGRAM COMMENTS 10 NA GPIBO CALL IBFIND NA BRDO 20 NA DEVO CALL IBFIND NA MblZ 30 V 27 C...

Page 79: ...l be programmed to a value of 1OV when the second statement is executed 3 10 10 Voltage Source Operate 0 The voltage source operate command performs essentially the same operations as the front panel OPERATE button The parameters included with this command are Oo Source output off Output OV Ol Source output w Output programmed value Upon power up or after receiving a DCL or SDC command the instrum...

Page 80: ...ent V l CALL IBSRE BRDO V return CMD AlQOX CALL IBWRT M617 CMD return Through the use of the G command the format of the data the instrument sends over the bus may be controlled as foIlows GO Send reading with prefix Example NDCV 1 23456E OO The calibration value is sent to the instrument when the second statement is executed 3 10 12 Non Volatile Memory Storage IL The Model 617 uses non volatile N...

Page 81: ...ng statements to place the instrument in the G1 mode V l CALL IBSRE BRDO V return CMD BOXGlX CALL IBWRT M617 CMD return RDB SPACE5 2O CALL IBRD M617 CMD return PRINT RD5 return When the second statement is executed the instrument will be placed in the Gl de The last two lines obtain the data string from the instrument and display it on the CRT Note that the prefix is absent from the data string Th...

Page 82: ...s caused it to do so Note that additional data and error conditions can be checked by using the Ul and U2 commands as described in paragraph 3 10 18 3 28 The Model 617 can be programmed to generate an SRQ under one or more of the following conditions 1 If an overrange condition occurs 2 When the data store memory is full 100 readings 3 If a reading is completed 4 When the instrument is ready to ac...

Page 83: ...usly received commands and is ready to accept addi tional commands over the bus Error Bit 5 Set when an error condition occurs as describ ed above Cleared by reading the error word with the U1 command RQS Bit 6 S if the Model 617 has asserted SRQ Bits 2 and 7 are not used and are always set to 0 Note that the status bite should be read to clear the SRQ line once the instrument has generated an SRQ...

Page 84: ...a method to positively identify the last byte in a multi byte transfer se quence Keep in mind that some controllers rely on EOI to terminate their input sequences In this case suppressing EOI with the K command may cause the controller input sequence to hang unless other terminator sequences are used The bus hold off mode allows the instrument to temporarily hold up bus operation when it receives ...

Page 85: ...may be changed by sending the will be transmitted only once each time the UO command is desired one or two characters after the Y command given To make sure that correct status is transmitted the However the capital letters A Z cannot be used as ter status word should be requested as soon as possible after the minators command is transmitted Special command sequences will program the instrument as...

Page 86: ... l ON TRIGGER A 0 CONTINUOUS TALK 1 ONE SHOT TALK 2 CONTINUOUS GET ulM K YY CR LF BGDOI L TERMINATOR ASCII CRLF LFCR k EOI BUS HOLD OFF O EOI HOLD OFF 1 NO EOI HOLD OFF 2 EOI NO HOLD OFF 3 NO EOI NO HOLD OFF sm OO DISASLEO 01 READING OVERFLOW OZ DATA STORE i LL 08 READING DONE 16 READY 32 ERROR DATA STORE O CONVERSION RATE 1 1 RDGISEC 2 1 RDGilO SEC 3 1 RDGIMIN 4 1 RDG lO MIN 5 1 RDG HR B TRIG SUT...

Page 87: ...t is still processing a reading from a previous trigger Number Error Set when a Out of range calibration or vol tage source value is received In a similar manner the U2X sequence allows access to instru ment data conditions When this command is transmitted the instrument will transmit the data condition word shown in Figure 3 13 the next time it is addressed to talk This informa tion will be trans...

Page 88: ...d lines 100 and 110 Line 120 and displayed lines 80 and 90 Line 100 sends the U2 com then sends the U2 command and the data condition word is mand and the data condition word is then obtained and obtained and displayed in lines 130 and 140 To show that displayed lines 110 and 120 To show that status is transmit status is transmitted only once a normal reading is then re ted only once a normal read...

Page 89: ...following lines to display a number error REMOTE 727 END LINE OUTPUT 727 DlV125X END LINE When the second statement is executed the instrument will display the number error message for about one second This error occurs with this example because an attempt is made to program a voltage value of 125V which is outside the range of the voltage source 102 35V 5 V 5 102 4V Model 8573 Programming Example...

Page 90: ... 85controller 2 Preamp settling time to12 is2 secondson preamp ranges 2 20 20OpA andmustbetaken into account by theuser A primary consideration is the length of time it takes to ob tain a reading once the instrument is triggered to make a con version The length of time will vary somewhat depending on the selected function and trigger mode Table 3 15 gives typical times 3 Volt time error also apply...

Page 91: ...rm irn plies the tet current through the unknown resistance is kept constant The voltage developed across the test resistance will of course depend on the valueof the insulation resis tance The Model 617 measures the generated voltage and calculates the resistance value accordingly The low com pliance voltage of the Model 617 2V on 2G0 range and lower except 3OOV during overload keeps error due to...

Page 92: ...MODEL 6147 MODEL 4801 R A I II 0 00 00 INPUT 0 00 0 cl 617 SET TO OHMS il r l EQUIVALENT CIRCUIT Figure 4 l Insulation Resistance Measurement Unguarded 4 2 ...

Page 93: ...D ON L J SAFETY SIGNAL SHIELD GUARD r _ 1 I WARNING SAFETY SWELO RECOMMENDED FOR GUARDED RESISTANCE MEASUREMENTS ABOVE 30GR UP TO 300 MA SE PRESENT ON GUARD ICOM 617 PREAMP I If l A D CONVERTER EQUIVALENT CIRCUIT Figure 4 2 Insulation Resistance Measurement Guarded1 4 3 ...

Page 94: ...IXTURE 617 SET TO II OHMS POMONA MODEL 4666 PATCH CORDS MODEL 6147 TRIAX MODEL 4601 CABLE TO BNC ADAPTER r r _ 0 00 00 617 PREAMP 6104 TEST FIXTURE __ IA D CONVERTER z V SOURCE T EQUIVALENT CIRCU T Figure 4 3 Insulation Resistance Measurement Using V I Ohms Mode 4 4 ...

Page 95: ...to voltmeter loading in this circuit can be given as ERROR RS x 100 Rs RIN Suppose for example a typical DMM with a 1OMR input resistance were used to make this measurement The error because of meter loading would be 1OOMQ ERROR x 100 91 elm2 1OOMR lOMQ Even if a DMM with an input resistance of 1OW were used the error would still be 1OOMQ ERROR x 100 9 1 error lC0MQ 1GO Such a large error would no...

Page 96: ...age In this manner leakage current characterization studies could be perfomed with only a single measuring in strument rather than requiring a separate voltage source As shown in Figure 4 5 a shielded test fixture such as the Keithley Model 6104 should be used to keep the measurement quiet and stable A good quality low noise cable such as the Model 4801 connected through a Model 6147 adapter shoul...

Page 97: ...s as shown in Table 4 l Input high sources the current These currents can be used to plot the I V current voltage characteristics over a substan tial range Table 4 I Diode Currents and Voltages Diode Range Current Diode Voltage VP 2kQ 20kfI lOOpA V lOO x 10 61 f 200 kCl lOpA V 10 x 10 q RI 2MQ 14 v 1 x 1041 RI ZOMR lOOnA V lOO x 10 q RI 200MQ 1OnA V 10 x 10 q RI 2GR 20GQ 200GD 1nA V 1 x 10 R R dis...

Page 98: ...equired instead the instrument can be placed in the V l ohms mode and the instrument will directly display the leakage resistance value with no calculations necessary on the part of the user This basic procedure could be used to test a number of capacitors on an automated basis A test fixture that holds a number of capacitors could be constructed and a Keithley Model 705 or Model 706 Scanner could...

Page 99: ... A DIODE CVRRENT II L lOO A l 0 2 0 6 Figure 4 7 Diode Curves 49 ...

Page 100: ...nt can then be used to calculate the resistance If the instrument is in the V I ohms mode the resistance will be calculated automatically Two resistance readings at two different voltage values will be required to calculate the voltage coefficient The voltage coefficient in V can then be calculated as follows 100 CR R Voltage Coefficient V R AV where R is the resistance with the first applied volt...

Page 101: ...L 4801 CABLE 617 SET TO il OHMS L l TEST FIXTURE MODEL 6104 SHIELDED TEST FIXTURE POMONA MODEL 4666 PATCH CORDS POMONA MODEL 4666 PATCH CORDS 617 PREAMP 617 PREAMP L s V SOURCE T EOUIVALENT ClRCUlT Figure 4 10 Configuration for Voltage Coefficient Studies 4 11 ...

Page 102: ...the tube and fall into the Faraday cup The amount of charge built up during the test will then be registered on the Model 617 The test can be repeated with other tubes as required In order for the test to be valid all tubes should be the same length and the same IC should be used in every case The tube that generates the smallest static charge as seen on the electrometer is the one with the best a...

Page 103: ...me that an external voltage of 2oOV is used If you programmed the Model 617 voltage source to 20V you could easily determine the actual resistance by noting the displayed value and moving the decimal point one place to the right The same general considerations apply to making voltage coefficient studies at voltages higher than 10 The basic configuration shown in Figure 4 12 would be used As discus...

Page 104: ...emperatures to reach normal operating temperature Typically it takes one additional hour to stabilize a unit that is 10 C x F out side the specified temperature range NOTE While rated accuracy is achieved after the two hour warm up period input bias cwent may require ad ditional time to come to its optimum level Allow two hours for input bias current to settle to less than 1OfA and eight hours to ...

Page 105: ...5 5 VERIFICATION PROCEDURES The following paragraphs contain procedures for verifving 5 Disable zero check and allow the reading to stabilize tv JlCa one mmute 1 Disconnect all cables from the Model 617 input 2 Place the input cap supplied with the instrument on the IN PUT co ector 3 Select the amps function 2pA range enable zero check and then enable zero correct 4 Connect a jumper between the re...

Page 106: ... is covered in Figure 5 l and connect the fixture to the instrument as shown in Figure 5 3 NOTE Disconnect floating sources when using this con figuration 14 Disable zero check and verify that the reading is within the limits given in Table 5 2 Enable zero check 15 Repeat steps 9 through 14 for the 2nA 2pA ranges For each range measure the actual resistor value and calculate the calibrarion voltag...

Page 107: ...lOGIl IZOOpAi 1OOGR A and ZO A NOTE SHORTING LINK IN PLACE MODEL 617 Figure 5 2 Connections for Amps Verification CXlOnAto 20mA Ranges Figure 53 Connections for Amps Verification i2pA to 2IlnA Ranges BNC CABLE IPOMONA 453 C l l 147 ADAPTER 4801 CABLE POMONA 3283 ADAPTERS n 1 L J MODEL 617 1OOOpFSTANDARD SHORT NG K IN PLACE A R CAPAC TOR Figure 5 4 Connections for Coulombs Verifications 5 4 ...

Page 108: ...4 Disable zero check and verify that the reading is within the limits listed in Table 5 3 Table 53 Limits for Volts Verification Applied Allowable Reading Range Calibrator Input I180 28W 200mV 190 000mV 189 87 to190 13mV 2 v 1 90000 v 1 I 990 to1 9010v 20 v 19 0000 v 18 990 to19 010V 200 v 190 000v 189 86 to190 14V 5 Repeat the procedure for the ZV ZOV and 200V ranges by applying the respective in...

Page 109: ...o check 7 Select the remaining ranges and repeat steps 5 and 6 for each range Table 6 4 Limits for Ohms Verification IZkQ 20M0 Ranges NOTE LEAVE GREEN DISCONNECTED 6011 CABLE Ill o uMozS p q ISHORTING LINK REMOVED Figure 6 6 Corrections for Ohms Verification 12kQ 20MQ Ranges 5 5 6 Ohms Verification 200MQ and GCl Ranges Accuracy of the 2OOMO 2G0 20Ga and 2OOGQ ranges may be verified as follows 1 Ac...

Page 110: ...ce the instrument in the volts mode select the 20V range and enable zero check Verify the display shows O CCO zkl count If not enable zero correct 2 Place the V 0 GUARD switch in the ON position 3 Connect the DC calibrator to the Model 617 use the con figuration in Figure 5 8 but with a short in place of the resistor Set the calibrator output to 19 OOS Disable zero check and note the reading 4 Ena...

Page 111: ...urce output is enabled 1 Connect the DMM see Table 5 l to the voltage source output terminals as shown in Figure 5 9 2 Select an appropriate DCV range on the DMM Altemate ly place the DMM in the autorange mode if desired 3 Press the DISPLAY button to view the voltage source value and turn on its output by pressing the OPERATE button 4 Using the ADJUST buttons set the voltage source output to w oov...

Page 112: ... MODEL 197 MODEL617 Figure 59 Connections for Voltage Source Verification 5 g 5 IO ...

Page 113: ...to zero the instrument allowing cancellation of internal offsets The ranging amplifier conditions the output stage signal into a 0 2V signal for the A D converter The A D converter uses both charge balance and single slope conversion techniques The heart of the dig l section is the 146805E2 CMOS pro cessor that supervises the entire operation of the instrument Additional digital circuits include t...

Page 114: ...1 r J7 I l I HI I VOLTAGE I CONTROL I I SOURCE dJ DISPLAY V SOURCE I I I LO I _ I I L l I A I V SOURCE ANALOG DIGITAL I r l n t110 t15 t5 t210 t24 5 es I 9 1 I POWER SUPPLY L DIGITAL m m I I I I Ii GNDL _ _ ___ I Figure 6 l Overall Block Diagram 6 2 ...

Page 115: ...stage is to provide low leakage characteristics of the input preamplifier Stage operation centers around a dual JFET Q308 Resistors R314 R342 R351 and R352 provide a means to balance the circuit with help of jumper W303 Depending on circuit off set jumper W303 should be placed in one of three positions A B or C Signal input is applied to the gate of the left JFET section through R334 The character...

Page 116: ...r VOUT IN 0 VOUT VOLTS _ ti IIN I I 0 VOUT VOUT II RF RF I OUT X R RF i OHMS CF 1OOOpF I QIN VOUT CF QIN OUT COULOMBS Figure 6 3 Electrometer Preamplifier Configuration ...

Page 117: ... rt21OV voltage swing requirement 21OV supplies are used Each transistor pair is operated in series to provide the necessary device breakdown voltage and power rating GAIN STAGE R301 CR318 iNPUT FROM OUTPUT OUTPUT GAIN STAGE j OMMON R321 Figure 6 6 Output Stage Configuration Volts and Ohms Circuit biasing components include R301 R302 R320 R321 R325 CR315 and CR316 Meanwhile CR318 and CR314 provide...

Page 118: ...e in volts and ohms it does not w Q306 CR306 21 T 1 24 R305 r PUT v k 3OM i IN TAGE RE wJ9 RE Ry RE RL SAIN F Qvv TAGE OUTPUT 3MMON k2 R323 xZCR316 R308 1 vu L 24v Q307 CR307 zy vvb R324 6 3 4 Ohms Voltage Source In the constant current ohms mode a bootstrapped voltage source is connected in series with a range resistor to force a constant current through the resistance being measured A simplified...

Page 119: ...ile the preamp input is shorted to in put low In amps and coulombs contacts on K301 connect the invert ing input and the output of the op amp together This con figuration gives the circuit unity gain allowing any input offset voltage to appear at the output Note that when zero check is enabled the input impedance is the combined im pedance of the feedback element in parallel with R334 which has a ...

Page 120: ...ng the reference phase the 2V reference voltage is selected while the signal from the ranging amplifier is selected during the signal phase Figure 6 12 shows a simplified schematic of the multiplexer and buffer amplifier U145 is the multiplexer IC which con tains CMOS devices that act as analog switches to select among the three input signals The multiplexer IC is con trolled by digital signals th...

Page 121: ...urce 6 5 A D CONVERTER The Model 617 uses an A D converter that utilizes both constant frequency charge balance and single slope techni ques This combination gives the instrument both high ac curacy and relatively fast conversion times A simplified schematic of the A D converter is show in Figure 6 15 along with an associated integrator waveform The charge balance phase begins when the input ENABL...

Page 122: ...hase lasts for 100msec At the end of this period the output of the integrator is resting at sane positive voltage Since the integrator output is connected to the non inverting input of the single slope comparator U137A1 the single slope comparator output remains high until the in tegrator output ramps in the negative direction During the single slope phase QlO8 is turned off to discon nect the inp...

Page 123: ...the DS terminal to act as a system clock crystal The signal is internally divided by five to obtain a bus operating frequency of 655 36kHz This signal is present at 6 6 2 Memory Elements Commands can be s t over the bus to the instrument and data can be requested from the instrument as well 6 6 4 IEEE 488 Bus The Model 617 has a standard IEEE 488 interface that allows the instrument to be programm...

Page 124: ...m mon remains within C3OV of ground In a similar fashion A D data is routed in from the A D con verter through opto isolator U121 The MPU reads this data through the TIMER terminal As data pulses come in an in ternal a bit timer is incremented until 256 counts have occur red When all counts have been taken an internal interrupt is generated which causes to MPU to read the timer data A separate sof...

Page 125: ... they are fed into the DATA input of U131 and U140 in serial form After all bits are shifted in data is strobed into the outputs of U131 and U140 The resulting 12 bit data is then applied to the digital inputs of U141 a 12 bit DAC Digital to Analog Converter This IC converts the digital information into an analog current out put The current output of U141 is then converted into a flOV full scale s...

Page 126: ... regulators The third winding of TlOl supplies the t5V sxrce that is used to power the digital circuits Rectification is done by elements of CR110 while filtering is performed by ClOl The supply voltage is regulated by UlOl which is a standard 7805 IC regulator The same secondary of TlOl that supplies the 5V digital scurce also supplies power to the primary of the electrometer section power transf...

Page 127: ...s WARNING Disconnect the Model 617 from the power line and all other sources before removing the top cover 1 Remove the screws securing the top cover to the rear panel and carefully lift the cover away from the instrument 2 Locate the line voltage switch adjacent to the POWER switch on the mother board Place the switch in the correct position as outlined in Table 7 l 3 Install a fuse consistent wi...

Page 128: ...free of its holder using a screwdriver The fuse holder is mounted on the inside of the rear panel 3 Replace the fuse only with the following type l A 25OV BUSS AGC 1116 Keithley Part No FIJ 86 l CAUTION Replacethe fuse only with the recommended type Installinga fuse with a larger rating may result in instrumentdamage 4 Install the top cover and secure it with the screws re moved earlier 7 4 CALIBR...

Page 129: ...ts optimum level Allow two hours for input bias current to settle to less than 1OfA and eigl hours to less than 5fA It is preferable in sensitive applications to leave the unit on continuously 7 4 4 Calibration Jumper A jumper located on the mother board allows the disabling or enabling of front panel and IEEE 488 bus calibration When the jumper is in the disabling position permanent NVRAM storage...

Page 130: ...mple witha 1 9V calibration point the display should be adjusted for a reading of 1 9GWV 4 Send the required calibration value preceded by the A command letter For example to calibrate the 2 W range at the 19oV calibration point send A19OX 5 Repeat steps l 4 for the remaining ranges and functions For maximum accura zero correct the instrument for each range and function 6 After all points have bee...

Page 131: ...2 function 7 4 9 Input Current Adjustment key on the computer At the command prompt type in the desired calibration command and press the return key For example type in LlX to perform NVRAM storage To exit Use the following procedure to null out any input current pre the program cleanly type in EXIT and press the return key at sent in the input stage The input current will then be the command prom...

Page 132: ...ollows E I X R where I is the nominal calibra tion current 190pA and R is the measured resistance value For example if the actual resistance value is lOlGR the calibration voltage value would be 19 19V NOTE Do not touch the body of the resistor to avoid contamination that could give erroneous results 2 Connect the DC calibrator and lOOGO resistor to the Model 617 as shown in Figure 7 4 Note that t...

Page 133: ...0 19OOOV 19 000 nA A19E 9X 20j4A 19 00 pA l OOOMQ 19 OOOOV 19 000 LA A19E 6X 20mA 19 000mA 1000 0 Q 19 OOOOV 19 000mA A19E 3X SHIELDED FIXTURE SHIELDED FIXTURE SEE FIGURE 7 l SEE FIGURE 7 l L L r GROUND LINK IN PLACE ITE LEAVE GREEN DISCONNECTED I BLACK LINK REMOVED Figure 7 5 Connections For Amps Calibration 20nA 20pA and 20mA Ranges1 Figure 7 4 Connections For Amps Calibration 20pA 7 7 ...

Page 134: ...ed in the following order 2COrnV 2V 20V and 200V ranges Proceed as follows 1 Select the volts function and place the instrument on the 2Gibnvrange 2 Set the DC calibrator to OV and connect it to the instru ment as shown in Figure 7 7 3 Zero correct the instrument by enabling zero check and then zero correct in that order 4 Disable zero check and set the calibrator output to 190 000mV 5 Either from...

Page 135: ...instrument and set the decade Up to 300V may be present on the shielded fixture in the guarded mode box to the required value 3 Select the ohms function and place the instrument on the 2GQ range 4 Zero correct the instrument by enabling zero check and then zero correct in that order 5 Disable zero check and allow sufficient time for the reading to settle Set the Model 617 calibration value to the ...

Page 136: ...ustment see Figure 7 9 so that the DMM reads a voltage of KY offset lOmV using the offset value obtained in step 4 7 Turn off the voltage source output ar 3 disconnect the DMM 7 4 16 Additional Calibration Points The electrometer calibration points discussed in the preceding paragraphs were chosen to optimize instrument accuracy without making the calibration procedure overly tedious and time cons...

Page 137: ...PECIAL HANDLING OF STATIC SENSITIVE DEVICES CMOS devices operate at very high impedance levels for low power consumption As a result any static charge that builds up on your person or clothing may be sufficient to destroy these devices if they are not handled properly Table 7 7 lists static sensitive devices used in the Model 617 When handling these devices use the precautions below to avoid damag...

Page 138: ...rd and rear panel as a single unit 4 The display board can now be removed as follows A Remove the two screws securing the display board to the front panel 8 Ffaydyt the DIP cable connected to the mother C Remove the display board by lifting up and back until the tabs at the bottom of the case are clear and then lift the display board free 5 The instrument can be re assembled by reversing the above...

Page 139: ... B CONNECTOR Inot shown cs 181 BNC CONNECTOR cs 249 REAR PANEL 617309 617 319 GROUND CLIP blot show BOTTOM COVER 30541 GROUND CLIP FRONT PANEL USHEUTTONS HIFT 228317 4 ELECTROMETER 228317 5 V SOURCE 228317 6 DATA STORE PROGRAM 228317 7 POWER 294653 Figure 7 11 Model 617 Exploded View 7 13 ...

Page 140: ...the zero common phase the display will appear as follows r o During the calibration reference phase the display will show P C Finally the display will show the following message during the signal phase P S To removetheinstrument from the diagnostic mode turn off the power The self diagnostic program can be used to test the front panel LEDs access the software revision level and enter a special mod...

Page 141: ...n the selected range and function as summarized in Table 7 12 This information can be used to determine if the ranging amplifier is working properly To do so select the desired range and function and apply an appropriate signal to the in put of the electrometer Measure the signal at the PREAMP and 2V ANALOG OUTPUT terminals and see if the correct scaling factor is applied For example with the inst...

Page 142: ...7 11 Relay Configuration r way mction Jolts 312 K309 c310 302 1304 X X X 305 X X IK306 301 X X X X X X X X X X X Range 200mV 2v 20 v 200 v 2 kfl 20 kQ 200 kQ 2MR 20MQ 200MQ 2al 20GQ 200GQ 2 PA 20 pA 200 pA 2 nA 20 nA 200 A 2 s 200 FA 2mA 20mA 200 pc 2 C 20 nc 200mC 2v 20 v ZeroCheck E 308 K311 X X X X X X X X X X X X X X X 307 K303 t t hms X X X X X X X X X X X X X X J X X l x l X X X X X X X X X ...

Page 143: ...components associated with the digital circuity including the IEEE 488 interface using the procedure given in Table 7 16 7 7 10 Display Board Check out the display board by using the procedure in Table 7 17 7 7 11 Voltage Source Check out the operation of the voltage source by using the procedure in Table 7 l Note that the power supply voltage should be checked first to ensure proper operation of ...

Page 144: ...ll cleati brush wipe the area thoroughly until it is free of flux or contaminants In some cases it may be helpful to tilt the board at an angle and brush con taminants away from the affected area allowing con taminated residue and methanol torunofftheboard 3 Wash the area again with fresh clean methanol 4 Once the area is thoroughly cleaned is should be dryed with pressurized dry clean air or nitr...

Page 145: ... 9v 11 Select2OOpA range 12 Apply 190fiA Input 19v 13 Enablezerocheck volts 14 ov ZeroCorrect ifnecessary 15 SelectOHMS 16 R304 pin1 1ov 0 1v Referenced to PREAMP OUT 17 R304 pin2 IV O OlV Referenced to PREAMP OUT 18 R304 pin3 O lV o o01v Referenced to PREAMP OUT Table 7 15 Ranging Amplifier Checks Item Component t Apply19OVDC toinput Apply19V DC toinput Apply1 9VDC toinput ANALOG OUTPUT and COM C...

Page 146: ...age supply control Metercomplete Table 7 17 Display Board Checks Step Itam Component Required Condition Remarks 1 Poweron 200V DC range zerocheckon Voltages referenced todigital comma 2 U201 pin9 5v _5 5v supply 3 u201 u202 Variable pulses Segmentdrivers pins 1l 18 4 U204 pins11 18 Variable pulses Digit drivers U205 oins 15 18 5 U209 binslo 15 lmsecnegative goingpulse every10msec 6 P1016 pin14 Dep...

Page 147: ...RCE HIand 102 35V LO Outputs 10 Program 102 4V output 11 U142 pin7 10 24V 12 V SOURCE HIand 102 4V LO outputs 13 OPERATE off 14 U141 pins 4 15 Pin4 high 5 15low 1 Remarks Voltages referenced tovoltage source common except asnoted Voltage source clock Voltage source data OPERATE on DAC Inputs OPERATE on DAC Inputs Current voltage converter Voltage source output OPERATE ON Current voltage converter ...

Page 148: ...4 respectively Parts in each table are listed alphabetically 1 Complete the service form which follows this section and in order of circuit designation return it with the instrument 2 Advise as to the warranty status of the instrument see the inside front cover for warranty information 8 3 MECHANICAL PARTS 3 Write the following on the shipping label ATTENTION REPAIR DEPARTMENT Mechanical parts are...

Page 149: ...pacitor O lpF 1OOV Metallized Polyester 3 B3 C4 C 305 1 Cl25 Capacitor O lpF 5OV Ceramic Film 3 F3 84 C 237 1 Cl26 Capacitor 0 1 F 5OV Ceramic Film 3 F4 C4 C 237 1 Cl27 Capacitor O lpF 5OV Ceramic Film 3183 D4 C 237 1 Cl28 Capacitor O OlpF lOOV Metalized Polypropylene 3 M c5 c 306 01 Cl29 Capacitor 1OpF 25V Aluminum Electrolytic l D2 E4 C 314 10 Cl30 Capacitor 0 47pF lOOV Metalized Polyester 3 B3 ...

Page 150: ...Channel Enhancement Mode MOSFET Resistor lOOn 5 XW Composition Resistor lOOa 5 XW Composition Resistor 43M1 5 1 4 W Composition Resistor 10MO 10 XW Composition Resistor Thick Film Resistor 5603 5 W Composition Resistor 30kR 5 4 W Composition Resistor Thick Film Resistor Thick Film Resistor lOMQ lo XW Composition Resistor 200kfl 5 W Composition Resistor 2OOk0 5 W Composition Resistor 100kQ 5 W Comp...

Page 151: ...X5 XW Composition Resistor 200kR 0 1 W MetalFilm Resistor 1 87k0 1 1JEW Composition Resistor lOOn l l EW Composition Resistor l5MR 10 W Composition Resistor 402k0 1 1 8W Composition Resistor 2 2kQ 536 W Composition Resistor 1kO 5 W Composition Resistor 430R 5 W Composition Resistor 6 8kR 5 1 W Composition Resistor lOOka 5 W Composition Resistor 22kQ 5 XW Composition Resistor 200kQ 5 W Composition ...

Page 152: ...rational Amplifier 741 IC Triple 3 Input NAND Gate 74HClO IC Triple 2 Channel Multiplexer CD4053BC IC DualVoltage Comparator LM393 IC Operational Amplifier TLC272C IC Programmable Operational Amplifier TLC271 IC Stage Shift Store Register MCI4094 IC 12 Bit DAC AD754lJN IC Operational Amplifier OP 14E IC Linear Op Amp 308A IC Quad Comparator LM339 C Triple 2 Channel Multiplexer CD4053BC Location Sc...

Page 153: ...ton Switch Pushbutton Switch Pushbunon Switch Pushbutton Switch Pushbutton Switch Pushbutton Switch Pushbunon Switch Pushbutton Switch Pushbutton Switch Pushbunon Switch Pushbutton Switch Pushbutton Switch Pushbunon Switch Pushbutton IC UDN2585A IC UDN2585A IC 3 to8 LineDecoder 74HCTl38 IC UDN2595A IC UDN2595A IC AnalogMultiplexer 4051 ich Pet A3 c2 D2 E2 2 Hl HI H2 H2 Liz H2 H2 H3 iii H3 F i H4 H...

Page 154: ...icon IA EOOPIV IN4006 CR307 Diode Silicon IA BOOPIV lN4006 CR311 Bridge Rectifier 1A IOOPIV CR314 Diode Silicon IA 6OOPIV lN4006 CR315 Diode Silicon lA 6OOPIV lN4006 CR316 Diode Silicon IA 6OOPIV lN4006 CR317 Diode Silicon IA 6OOPIV IN4006 CR316 Diode Silicon IN4146 CR319 Diode Silicon IA 6OOPIV lN4006 CR320 Diode Silicon IA 6OOPIV lN4006 CR321 Diode Silicon IN4146 CR322 Diode Silicon IA EOOPIV IN...

Page 155: ...esistor 2 2kO 5 W Composition Resistor 330kSl lo W Composition Resistor 33OkQ 10 iW Composition Resistor lOOkQ 0 1 W MetalFilm Resistor 1000 5 W Composition Resistor 56OQ IO hW Composition Resistor 1000 5 W Composition Resistor 47fl 5 W Composition Resistor 56M2 10 hW Composition Resistor 5 1 kQ W Composition Resistor 2 2kQ 5 W Composition Resistor IOOGQ 2 1 5W Resistor IOOMQ I 1 6W Resistor 250GR...

Page 156: ...tion Transformer Power IC 8 Stage Shift Register MC14094BCP IC Hex Inverter 74HC04 IC Hex inverter 74HC04 IC Operational Amplifier 741 Not Used IC Regulator 5V 7805 IC Adjustable Regulator LM337L IC Voltage Regulator 5V 78L05A IC Low NoiseOp Amp VR301 Regulator selected withR213 VR302 Regulator ZenerDiode 9 1V 1W lN4739A VR303 Regulator ZenerDiode 9 1V 1W lN4730A VR304 Regulator ZenerDiode 33V lW ...

Page 157: ...y 617 303 BlackBinding Post J1003 J1007 BP l O Red Binding Post J1002 J1004 J1006 BP 11 2 Binding PostfJ1005 BP 15 BNC ConnectorIJlOOB J1009 cs 249 Triax Connector JlOOl CS 181 Protective Cap CAP 18 Ground Clip 617 319 LineCord co 9 Pushbutton Power 29465 3 Pushbutton Shift 228 317 4 Pushbutton Electrometer 228 317 5 PushbuttonW Source 228 317 6 Pushbutton DataStore Program 228 317 7 Fuse Holder f...

Page 158: ...Figure 82 Mother Board Component Location Drawing Dwg No 617 100 Sheet 1 of 2 a13 a14 ...

Page 159: ...Figure 6 2 Mother Board Component Location Drawing Dwg No 617 100 Sheet 2 of 2 81516 16 ...

Page 160: ...8LWLL 8 ON fL9 ON EMa 6uyma uope ol auauodtuo3 p eog Aqds a 18 amby 9lOld L J ii i ...

Page 161: ......

Page 162: ...PI0 I MAIN POWER SiJPPLY Figure 8 5 Mother Board Schematic Diagram Dwg No 617 106 Sheet 1 of 3 a 2116 22 ...

Page 163: ... B h cCOMPUTER Figure 6 6 Mother Board Schematic Diagram Dwg No 617 106 Sheet 2 of 3 8231824 ...

Page 164: ... tI3lkl3AN03 a v T f I I Y I 0 I 4 I 3 t a 3 I 8 I vPAGE3OF ...

Page 165: ...I n I m I I 7 7 I N I m r I 7 I ...

Page 166: ...w c cl ...

Page 167: ...ain procedures for verify ing instrument accuracy with each of the four measuring functions volts ohms amps and coulombs In addition A 2 a procedure to verify accuracy of the internal voltage source is also included These procedures are intended for use only by qualified personnel using accurate and reliable test equipment If the instrument is out of specifications refer to Section 7 for calibrati...

Page 168: ...mA 2mA 200pA 20 A 2k4 2oon A 20nA 2nA 2OOpA Connect the Model 617 to the Model 263 as shown in Figure 1 and perform coulombs verification as follows 1 Using the COUL ahive charge source of the Model 263 select the 2nC range 2 Place the Model 263in the coulombs function and per form zero correction by enabling zero check and zero correct in that order 3 Release zero check on the Model 617 4 Program...

Page 169: ...orrect the Model 637by enabling zero check and zero correct in that order 3 Set the Model 26 3to the lkQ range and while in OPERATE press ZERO to source zero ohms to the Model 617 4 Release zero check on the Model 617 and allow the reading to settle 5 On the Model 617 press SUPPRESS to cancel offset and test lead resistance 6 On the Model 263 source the lk0 resistor to the Model 6lZ The actual val...

Page 170: ...le 3 Limits for Ohms Verification Calculated Limit 263 Allowable 617 Reading Reading Equipment Error Limit WC to 28W x 0 16 0 0004 kn 263 Reading k Limit x 0 13 0 001 kB 263 Reading Limit x 0 23 0 01 kfl 263 Reading Limit x 0 225 O OOOlMl 263Reading Lit x 0 2125 0 001 MQ 263 Reading Limit x 0 23 0 01 MQ 263 Reading i Lit x 1 4 O OOOlGO 263 Reading t Limit x 1 275 0 001Gfi 263Reading Lit x 1 1 0 01...

Page 171: ...put impedance of the unit is greater than 2OUlQ 1 Connect the DC calibrator Model 263 and the Model 617 as shown in Figure 5 2 Place the Model 617in the volts function select the 20V range and enable ZERO CHECK Verifythat the display shows O OOOV 1 count If not enable ZERO CORRECT 3 Enable GUARD on both the Models 617 and 263 4 On the Model 263 select the 200GQ range and press ZERO to source zero ...

Page 172: ... VOLTS OHMS MODEL CA 18 l MODEL 196 MODEL 617 WLTAGE SOURCE GAIN ADJUSTMENT Figure 4 Voltage Source Verification Setup r SHORTINGUNK DISCONNECTED SANANACABLE I BANANACABLE Figura 5 Input Impedance Verification Setup A 7 ...

Page 173: ...be entered and used even if NVRAM calibration storage is disabled Note however that calibration parameters will be lost once power is turn ed off unless they are stored in NVRAM The calibration jumper location and the disabled enabled positions are indicated in Figure 6 WARNING Turnoffthe instrumentand disconnect the line cord before removing the top cover to reposi tion the calibration jumper Req...

Page 174: ...oltage source is calibrated third since this is a manual adjustment This allows the digital calibration procedures to be grouped together In addition to the above sequence the ranges for each function must be calibrated in the order given Note that you should never calibrate a range using a suppress or a zero correct value taken on a different range Manual Calibration Adjustments After performing ...

Page 175: ...ews removed earlier C Voltage Source Calibration Use the following procedure to calibrate the voltage source Since the voltage source is independent from the electrometer section voltage source calibration can be per formed at any time WARNING Hazanfous voltage will be used in Some of the following steps 1 Connect the Model 196DMM to the voltage source out put as shown in Figure 8 2 From the front...

Page 176: ...e display of the Model 617to read 19OOOpA using the ADJUST buttons of the Model 617 8 Program the Model 263 to output OO OOOpA by press ing ZERO on the Model 263 9 On the Model 617 disable zero correct and suppress 10 Using Table 5 as a guide select the next electrometer range and calibrator range and repeat the basic pro cedure in steps 3 through 9 Calibrate all the elec trometer ranges listed in...

Page 177: ...t the Model 617by enabling zero check and zero correct in that order 5 Program the Model 263to output the 1OGQ resistor The actual value of that resistor will be displayed by the Model 263 6 Release zero check on the Model 617 and allow the resistor reading to settle 7 Adjust the display using the ADJUST buttons of the Model 617 to correspond to the reading on the Model 263 8 Disable guard on the ...

Page 178: ...and the following message will be displayed briefly Stor Also constants for uncalibrated ranges are derived at this point Ifthe calibration jumper is in the disable position NVRAM storage will not take place and the following message will be displayed briefly Out Only changed constants are affected with uncalibrated ranges unaffected The new calibration constants will be used by the instrument unt...

Page 179: ...st when the Model 617is turned off on the computer and follow the instructions on the CKI display 10 CLEAR 727 708 CLEAR BEEP 20 IlISP i i CI IWEI TTHE263 TOTHE6 17 FIG F kHIl THEE TI S ILIRI E FIG 9 30 DISP SET EXT U SOURCE TO OUTPUT 90 000V TO 263 OISP 40 DISP PRESS CONT TO CONTINUE 50 PAUSE 60 CLEfiR 70 OUTPUT 708 FiR3 J190E 12X 263 program for 150pA 80 DATA 3 00000000019 5 000000013 9 000019 1...

Page 180: ... mAu U X 617 send cal value 550 WAIT 2000 560 NEXT I 570 OUTPUT 727 Z0N0R4X 617 select 200V range 580 OUTPUT 708 FSOIXw 263 source ert U to 617 590 WAIT 2000 600 BEEP 2 200 0 OUTPUT 727 A190X 617 send cal value 610 WAIT 2000 620 OUTPUT 727 ClFZR8X 1 617 select 20Gohm range 630 PRINT VOLTS RANGES CALIBRATED 640 PRINT All 0 PRINT 650 OUTPUT 708 FOREWIX 263 select 10Gohm range Quard on 660 BEEP 0 DIS...

Page 181: ... 200kohm 20kohm 880 BEEP DISP DISP DO YOU WISH TO PERMbNENTLY STORECAL CONSTflNTS Y N 7 890 INPUT B5 900 CLEAR 0 IF B Y THEN 940 910 DISP CAL CONSTANTS NOT STORED 6 DISP 920 OISP ALTERED RfiNGES TEMPORARILY CAL IBRATED 930 GOT0 970 940 OUTPUT 727 LlX 617 store cai constants 350 DISP IF JUMPER IN ENABLE POSITION 960 DISP DISP ALL FUNCTIONS RANGES PERMANENTLYCALIBRATED 970 END 617 CALIBRATION PROGRA...

Page 182: ... check one B Drifts Q Unable to zero 0 Unstable 0 Will not read applied input Q Overload a Calibration only 01 Data required D Certificate of calibration required attach any additional sheets as necessary Show a block diagram of your measurement system including all instruments connected whether power is turned on or not Also describe signal source Where is the measurement being performed factory ...

Page 183: ...arate procedures are provided for performing digital calibration from either the front panel or over the IEEE 488bus Digital calibration over the bus is automated using a BASIC program run by the HP 85 computer Using the Model 263to verify and calibrate the Model 617simplifies the procedure and eliminates the need to build a test fixture A l ...

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Keithley 617, Instruction Manual

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