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Model 6487 Reference Manual

Applications Guide

G-5

Figure G-2

Voltage burden considerations

Noise and source impedance

Noise can seriously affect sensitive current measurements. The following paragraphs dis-
cuss how source resistance and input capacitance affect noise performance.

Source resistance

The source resistance of the DUT will affect the noise performance of current measure-
ments. As the source resistance is reduced, the noise gain of the picoammeter will
increase, as we will now discuss.

shows a simplified model of the feedback picoammeter. R

S

and C

S

represent

the source resistance and source capacitance, V

S

is the source voltage, and V

NOISE

is the

noise voltage. Finally, R

F

and C

F

are the feedback resistance and capacitance respectively.

The source noise gain of the circuit can be given by the following equation:

Note that as R

S

decreases in value, the output noise increases. For example, when R

F

= R

S

,

the input noise is multiplied by a factor of two. Since decreasing the source resistance can
have a detrimental effect on noise performance, there are usually minimum recommended
source resistance values based on measurement range.

summarizes minimum

recommended source resistance values for various measurement ranges. Note that the rec-
ommended source resistance varies by measurement range because the R

F

value also

depends on the measurement range.

Rs

Vs

I

M

=

R

S

V

S

- V

B

I

V

B

(Voltage

Burden)

+

-

+

-

6487

V-Source

Model of 6487 Picoammeter

Input Characteristics Before

Voltage Offset Correction

Output V

NOISE

Input V

NOISE

1

R

F

/R

S

+

(

)

=

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Содержание 6487

Страница 1: ...www keithley com E C N E D I F N O C F O E R U S A E M R E T A E R G A Reference Manual 6487 901 01 Rev B March 2011 Model 6487 Picoammeter Voltage Source Model 6487 Picoammeter Voltage Source...

Страница 2: ...g license html Keithley s standard terms and conditions of sale in effect at the time of acceptance of buyer s order by Keithley shall apply to all purchase of goods and performance of services from K...

Страница 3: ...tional Electrotechnical Commission IEC Standard IEC 60664 Most measurement control and data I O signals are Measurement Category I and must not be directly connected to mains voltage or to voltage sou...

Страница 4: ...ent shows that the surface may be hot Avoid personal contact to prevent burns The symbol indicates a connection terminal to the equipment frame If this symbol is on a product it indicates that mercury...

Страница 5: ...ngs 1 8 Front panel setup operation 1 9 Remote setup operation 1 9 Menus 1 12 Main menus 1 12 Configuration menus 1 13 SCPI programming 1 14 Optional command words 1 14 Query commands 1 14 2 Measureme...

Страница 6: ...t measurements 3 7 Procedure 3 7 Programming example 3 11 Ohms measurements 3 11 Overview 3 11 Procedure 3 12 SCPI programming ohms measurements 3 14 Programming example ohms measurements 3 15 Voltage...

Страница 7: ...olling relative 5 2 SCPI programming relative 5 4 mX b m X b reciprocal and logarithmic 5 5 mX b and m X b 5 5 Configuring and controlling mX b and m X b 5 5 Logarithmic 5 6 SCPI programming mX b m X...

Страница 8: ...ing external devices 8 12 Source mode logic control 8 14 Setting digital output lines 8 14 SCPI programming digital output pattern 8 15 Front panel operation limit tests 8 16 Limit test configuration...

Страница 9: ...and service request commands 10 9 Status register sets 10 10 Register bit descriptions 10 10 Queues 10 17 Output queue 10 18 Error queue 10 19 11 Common Commands Common commands 11 2 12 SCPI Signal O...

Страница 10: ...3 Calibration cycle 16 3 Recommended calibration equipment 16 3 Calibration errors 16 4 Calibration menu 16 5 Aborting calibration 16 6 Current calculations 16 6 Calibration procedure 16 7 Preparing f...

Страница 11: ...Bus management lines D 5 Handshake lines D 5 Bus commands D 6 Uniline commands D 9 Universal multiline commands D 9 Addressed multiline commands D 10 Address commands D 10 Unaddress commands D 10 Com...

Страница 12: ...edance G 5 Electrostatic interference and shielding G 7 Making connections G 10 Typical range change transients G 12 Steps to minimize impact of range change transients G 16 Zero check on off response...

Страница 13: ...nection line voltage setting fuse replacement power line frequency and the power up sequence Front panel operation Shows the location of front panel controls displays and indicators Status and error m...

Страница 14: ...nd Sourcing Voltage Section 4 Range Units Digits Rate and Filters Section 5 Relative mX b m X b and log Section 6 Buffer and Sweeps Section 7 Triggering Section 8 Limit Tests and Digital I O Section 9...

Страница 15: ...resent on the termi nal s Use standard safety precautions to avoid personal contact with these voltages The symbol on an instrument shows that it can source or measure 1000 volts or more including the...

Страница 16: ...ertificate of calibration Model 6487 User s Manual P N 6487 900 00 Product information CD ROM that contains PDFs of the User s and Reference Manuals Reference manual If a printed copy of the Model 648...

Страница 17: ...oltage may cause dam age to the instrument possibly voiding the warranty Figure 1 1 Rear panel 2 Before plugging in the power cord make sure that the front panel power switch is in the off O position...

Страница 18: ...factory default setting is Auto Detect enabled If the power line is noisy auto detect may not be able to lock in on a frequency If this occurs set the frequency manually This may be accomplished usin...

Страница 19: ...FREQ 60Hz 4 After the detected line frequency is displayed information on the selected remote interface is displayed a GPIB If the GPIB is the selected interface the instrument will display the selec...

Страница 20: ...ttings The Model 6487 can be restored to one of five setup configurations factory default FACT three user saved USR0 USR1 and USR2 and bus default GPIB As shipped from the factory the Model 6487 power...

Страница 21: ...en SETUP to display the power on menu 2 Use the or RANGE key to display the desired setup FACT USR0 USR1 USR2 or GPIB 3 Press ENTER Remote setup operation Saving and restoring user setups The SAV and...

Страница 22: ...f 10 Moving 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 Test...

Страница 23: ...rigger Link Line IMM 1 0 1 NEVER 2 Units No effect Voltage Source Operate Amplitude Range Current Limit 10V Range Interlock Sweeps Start Voltage Stop Voltage Step Voltage Center Voltage Span Voltage D...

Страница 24: ...ng the menu key has no effect Press the LOCAL key to place the unit in local operation then press the MENU key to access the menu items Table 1 3 Main MENU structure Menu item Description Reference CA...

Страница 25: ...nd LOG math functions Section 5 FILT Configure median and average filters Section 4 REL Enter relative value Section 4 OPER Select DC or SWEEP mode set source amplitude and current limit Section 3 COM...

Страница 26: ...tional command words and query commands Optional command words and query commands are summarized as follows Optional command words In order to be in conformance with the IEEE 488 2 and SCPI standards...

Страница 27: ...picoammeter for both current and ohms measurements Using a test fixture Discusses using general test fixtures as well as the Model 8009 test fixture Interlock Covers interlock connections and operatio...

Страница 28: ...tor is a 3 lug female triax connector Figure 2 1 Make con nections using a male terminated triax cable Low noise input cables page 2 3 Figure 2 1 Triax input connector Voltage source output connectors...

Страница 29: ...use low noise cables for INPUT connections The following low noise cables are recommended for use with the Model 6487 Model 237 ALG 2 Triax Cable This 2m 6 6 ft low noise triax cable terminated with a...

Страница 30: ...h banana plugs such as the Model 8607 High Performance Banana Cables Model 8607 High Performance Banana Cables Consists of two high voltage 1000V banana cables The cables are terminated with banana pl...

Страница 31: ...uired for DUTs capable of forcing voltages 505V or greater Damage to the instrument may result if volt ages greater than 505V are forced on the Model 6487 INPUT HI Ohms measurement connections Basic c...

Страница 32: ...that the resistance to be measured becomes shorted or an incorrect value of resistance is inserted in the test setup the voltage source can permanently damage the Model 6487 To prevent this damage th...

Страница 33: ...200 A 50k 2mA or 20mA 510 The series limiting resistor should have a minimum power rating of Example If measuring 100G resistances using an external voltage source of 750V and thus a lowest necessary...

Страница 34: ...eak The Model 6487 does not internally limit the LO to chassis voltage Exceeding 505V can cre ate a shock hazard If it is possible for the DUT or external supply to present more than 505V to the input...

Страница 35: ...vent contact with live circuitry The test fixture must have a screw terminal that is used exclusively for connection to safety earth ground t okfkd To provide protection from shock hazards the test fi...

Страница 36: ...ontaminants on connector and terminal insulators can significantly decrease the leakage resistance resulting in excessive leakage currents Contaminants on DUT and test circuit components can create a...

Страница 37: ...ld leave a charged device in the fixture Screw terminal on the test fixture for safety earth ground For typical connections to the Model 6487 refer to Figure 2 8 Figure 2 8 Typical connections for mea...

Страница 38: ...between picoammeter LO and chassis ground common mode voltage is 505V The Model 6487 does not internally limit the LO to chassis voltage Exceeding 505V can create a shock hazard If it is possible for...

Страница 39: ...terlock is asserted and the voltage source cannot be placed in operate on the 50V or 500V voltage source ranges and optionally for the 10V range t okfkd If the voltage source is operating when the int...

Страница 40: ...s a scaled inverting 2V output A full scale reading corresponds to 2V output t okfkd The maximum safe voltage between the voltage source or ammeter and chassis ground common mode voltage is 505V DC Ex...

Страница 41: ...tion The effects of this resistance on analog output accuracy are negligible Rel and the result of mX b m X b or LOG have no affect on the analog output The 2V analog output is scaled only to the act...

Страница 42: ...ge of Model 6487 could cause errors if it is high in relation to the voltage of the measured circuit Noise Noise generated by source resistance and source capacitance See Model 6487 User s Manual Appe...

Страница 43: ...o zero check and zero correct Current measurements Provides a basic procedure to measure current Ohms measurements Covers methods to set up and use the ohms measurement function Voltage source operati...

Страница 44: ...tage 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 current measurement capabilities...

Страница 45: ...correction via remote connect the triax shielding cap to the INPUT then send CALibration UNPRotected VOFFset Autozero To help maintain stability and accuracy over time and changes in temperature the M...

Страница 46: ...eck is enabled on the input amplifier is reconfigured to shunt the input sig nal to low with the input impedance Figure 3 1 klqb The ZCHK key toggles zero check on and off If zero check is enabled ZER...

Страница 47: ...ge displayed 2 Select the range that will be used for the measurement or select the lowest range 3 Press REL to enable zero correct ZCORRECT ON message displayed briefly 4 Press ZCHK to disable zero c...

Страница 48: ...t measured at that moment will become the correction value Zero correction can then be applied and zero check disabled This acquire method makes it convenient if you need to re zero the instrument oft...

Страница 49: ...safe voltage between picoammeter LO and chassis ground common mode voltage is 505V The Model 6487 does not internally limit the LO to chassis voltage Exceeding 505V can create a shock hazard If it is...

Страница 50: ...e I key to make sure the current function is selected Step 2 Enable zero check Zero check should always be enabled before making connection changes The ZCHK key toggles zero check on and off When on t...

Страница 51: ...of the Model 6487 Fundamental information on making connections to the picoammeter input is provided in Section 2 Step 6 Disable zero check and take a reading from the display If the readings are noi...

Страница 52: ...ion 13 If there is no reading available when DATA is sent an error 230 will occur B FUNCtion CURRent Use this command to select the current function instead of the ohms function C INITiate To return a...

Страница 53: ...measurements Overview To measure ohms with the Model 6487 you must set up the voltage source to the desired range value and current limit see Voltage source operation page 3 15 choose an appropriate c...

Страница 54: ...current range or enable auto range Use the manual RANGE keys to select a manual measurement range or press AUTO to enable auto range When using manual ranging choose an appropriate value based on the...

Страница 55: ...ayed on the front panel for both normal readings and buffer recall readings for any ohms readings where the voltage source went into compliance Figure 3 3 Connections for ohms measurements Black LO Re...

Страница 56: ...tput on and off Additional voltage source commands control volt age sweeps see Section 6 Table 3 6 SCPI commands basic ohms measurements Commands Description Default Ref Measurements SENSe 1 CURRent D...

Страница 57: ...nable ohms function SOUR VOLT STAT ON Put voltage source in operate SYST ZCH OFF Disable zero check READ Trigger and return one reading Voltage source operation Voltage source edit keys The V SOURCE a...

Страница 58: ...to advance to the cur rent limit display and select the desired current limit The current limit display offers different choices depending on the source range Table 3 7 Pressing ENTER or EXIT from thi...

Страница 59: ...or larger wire Step 3 Turn on voltage source Press the OPER key to turn on the voltage source output The VOLTAGE SOURCE OPERATE indicator will turn on rqflk Do not connect external sources to the 648...

Страница 60: ...operate state is changed to on The exception is the 10V range where the interlock is optional The OPERATE light and front panel display do not indicate the difference between 0V output and high imped...

Страница 61: ...ccommodates the value sent A value of 10 01 for example will select the 50V range C ILIMit NRf Use this command to set the voltage source current limit to 25 A 250 A 2 5mA or 25mA Note however that th...

Страница 62: ...y range other than the 10V range Attempting to turn off the interlock state while on the 50 or 500V ranges will generate a 221 Settings Con flict error Upranging from the 10V range will always cause t...

Страница 63: ...fer and storing these differences in a buffer designated V Delta Both from the front panel and via remote A V ohms readings always come from the V Delta buffer The purpose of the alternating voltage o...

Страница 64: ...he decay period of course depends on the RC time constant of the circuit being tested Figure 3 7 demonstrates the clear advantages of A V ohms The decaying curve shows how current decays time without...

Страница 65: ...en press ENTER The unit will prompt for the time that the voltage source value will be at each phase in the A V cycle TIME 15 00 s 4 Enter the desired time then press ENTER The Model 6487 will prompt...

Страница 66: ...be armed Alternatively from this reading display press CONFIG I and change the selection back to NORMAL to take regular not A V ohms readings Pressing the EXIT or OPER key while A V ohms is in progre...

Страница 67: ...dis abled during the A V ohms run After the desired number of cycles has completed or an OHMS AVOL ABORt command is received the display will be restored RANGE RANGE RDG NO 10 Reading Value Amps Readi...

Страница 68: ...information Normal ohms with A V ohms Normal ohms SENS OHMS STAT is not compatible with A V ohms since the latter relies on differences between current measurements in time Therefore the I key is ign...

Страница 69: ...ng that changes the timing between readings would make it impossible to continue averaging in with any previously collected readings Therefore the following command is locked out from the GPIB while A...

Страница 70: ...ms mode commands Path to A V ohms commands Arm A V ohms mode Query if A V ohms is armed 1 armed Abort A V ohms mode Set high voltage value 505 to 505V Set time interval for each phase Query number of...

Страница 71: ...if the unit is still in the idle state See Section 7 klqb We strongly recommend that no commands except for the INIT be sent after sending the OHMS AVOL ARM command B OHMS AVOLtage ABORt This command...

Страница 72: ...cycles to run A V ohms A cycle is defined as one V High and one V Zero step H OHMS AVOLtage UNITs name This command sets the units that the A V ohms readings will be stored and returned in amps or ohm...

Страница 73: ...elect 20mA range turn off auto OHMS AVOL VOLT 5 Set high voltage to 5V OHMS AVOL ONES OFF Disable one shot mode OHMS AVOL CLE AUTO ON Enable buffer auto clear OHMS AVOL TIME 10 Set time per phase to 1...

Страница 74: ...udes the SCPI commands for remote operation Rate Provides details on reading rate selection Includes the SCPI commands for remote operation Damping Provides details on damping including the SCPI comma...

Страница 75: ...e applied signal Up ranging occurs at 105 of range while down ranging occurs at the range value For example if on the 20 A range the instrument will go up to the 200 A range when the input signal exce...

Страница 76: ...Press ENTER when the desired range is flashing klqb If you attempt to select an incompatible range limit it will be ignored and TOO LARGE or TOO SMALL will be displayed briefly For example if the low...

Страница 77: ...value will not be displayed with the 6 digit setting SCPI programming range and digits Table 4 2 SCPI commands digits Commands Description Default CURRent RANGe UPPer n AUTO b ULIMit n LLIMit n For D...

Страница 78: ...efaults CURR RANG 0 02 Set to 20mA range DISP DIG 3 5 Set display resolution to 3 digits Table 4 3 Ranges and values Range n value Display 5 digit resolution 20mA 2mA 200 A 20 A 2 A 200nA 20nA 2nA 2E...

Страница 79: ...ough to settle a step response 100ms Figure 4 1 Speed vs noise characteristics The rate setting is global for all ranges Therefore it does not matter what range is pres ently selected when you set rat...

Страница 80: ...b The SLOW MED or FAST annunciator will only turn on if the set PLC value corresponds exactly to the slow 5 or 6 PLC for the respective frequency of 50 or 60Hz medium 1 PLC or fast 0 1 PLC integration...

Страница 81: ...y measurements caused by noisy input signals The Model 6487 uses two types of filters median and digital The displayed stored or transmitted reading is simply the result of the filtering processes Not...

Страница 82: ...from the updated sample of readings Median filter operation The median filter operates as a moving type filter For exam ple if the median filter is configured to sample 11 readings Rank 5 the first f...

Страница 83: ...does not wait for the stack to fill before releasing readings Repeating Filter Takes a selected number of reading conversions averages them and yields a reading It then flushes its stack and starts ov...

Страница 84: ...the zero check operation is per formed or the range is changed Digital filter control To configure the average filter 1 Press CONFIG then FILT 2 Set the display to AVERAGE ON then press ENTER The pres...

Страница 85: ...ount to 20 AVER TCON MOV Select moving filter AVER ON Enable digital filter Table 4 6 SCPI commands filters Commands Description Default For median filter SENSe 1 MEDian RANK n STATe b For digital fil...

Страница 86: ...xplains 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 includes...

Страница 87: ...ble whenever a math function is enabled or disabled Setting and controlling relative From the front panel there are two ways to set the Rel value You can use the input reading as the Rel value or you...

Страница 88: ...d 2 To change the Rel value use the RANGE and cursor keys and change the value To change Rel polarity place the cursor on the polarity sign and press either manual RANGE key To change the Rel range pl...

Страница 89: ...or more Rel ed readings They will not trigger fresh new readings Use the INITiate command to trigger new readings see Section 7 for details on INITiate If the instrument is programmed to perform a fi...

Страница 90: ...S Rel input signal SYST ZCH OFF Turn off zero check INIT Trigger reading s CALC2 DATA Request Rel ed reading mX b m X b reciprocal and logarithmic mX b and m X b The following math operations manipula...

Страница 91: ...is used for both the mX b and the m X b calculations Therefore changing either configuration of the mX b or the m X b calculation also changes the other calculation s configuration 7 To change the un...

Страница 92: ...front panel CONFIG MATH menu Functions names include MXB mX b RECiprocal m X b and LOG10 B KMATh Use these commands to set the M scale factor B offset and units for the MX B and reciprocal math functi...

Страница 93: ...se the DATA command to return CALC1 readings However you can use the DATA LATest command to return the last CALC1 reading after aborting the measurement process After sending the INITiate com mand to...

Страница 94: ...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...

Страница 95: ...up the instrument for the desired configuration 2 Press CONFIG CONFIGURE will be displayed 3 Press STORE The present buffer size in readings is displayed 4 Use the cursor and keys and the RANGE and ke...

Страница 96: ...dings RANGE RANGE RDG NO 10 Reading Value Vsource RDG NO 9 Reading Value Vsource RDG NO 8 Reading Value Vsource RDG NO 7 Reading Value Vsource RDG NO 6 Reading Value Vsource RDG NO 5 Reading Value Vso...

Страница 97: ...gs Avg is the mean of the buffer readings klqb If any readings stored in the buffer are the result of an overflow or overvoltage condition the buffer statistics calculation will not be performed Buffe...

Страница 98: ...e the voltage source went into compliance Table 6 1 SCPI commands buffer Commands Description Default Ref TRACe CLEar FREE POINts n ACTual FEED name CONTrol name TSTamp FORMat name DATA MODE TRACe Sub...

Страница 99: ...rol name Name parameters NEXT Enables the buffer and turns on the asterisk annunciator After the buffer stores the specified number of readings the asterisk annunciator turns off NEVer Disables the bu...

Страница 100: ...order of the listed data elements set by this command G CALCulate3 FORMat name This command selects the statistic to be returned by CALCulate3 DATA see Ref H Name parameters MINimum Select the lowest...

Страница 101: ...Mean Statistic for Buffer Readings CALC3 FORM MEAN Select mean statistic CALC3 DATA Request mean statistic Voltage sweeps The Model 6487 voltage source can be used to generate voltage sweeps from a s...

Страница 102: ...rt STRT value entry menu Likewise a step size larger than the stop start interval results in the message STEP TOO BIG Note that as long as the front panel V MODE setting is SWEEP the TRIG key will fun...

Страница 103: ...sweep The SCAN annunciator will be on to show the sweep is armed 7 To start a sweep press the TRIG key The voltage source will be placed in operate the sweep will be performed and readings will be st...

Страница 104: ...ands trigger model com mands and buffer TRACe subsystem commands are locked out Sending any of the commands listed below generates the error code 840 Not allowed with sweep on SOUR VOLT LEV IMM AMPL S...

Страница 105: ...is that the sweep delay is added between the setting of the source to the new value and the acqui sition of the reading The implications of this fact are that you must have the trigger and arm counts...

Страница 106: ...et true when the SOUR VOLT SWE INIT command is received and it remains high until either the last sweep point is completed or a SOUR VOLT SWE ABOR command is received A VOLTage SWEep STARt NRf This co...

Страница 107: ...STARt and STOP and are another way to specify the sweep F VOLTage SWEep DELay NRf This command programs the delay period which is the time that the Model 6487 waits after sourcing the voltage before s...

Страница 108: ...to RST defaults 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 ELE...

Страница 109: ...so explains how to configure the trigger model from the front panel SCPI programming Includes the commands used to configure the trigger model and the commands to control the measurement process Exter...

Страница 110: ...operation Arm In Source Immediate GPIB Timer Manual TLink STest STest BSTest Arm Event Detector Trigger Event Detector Trigger Delay MEASURE Action No Yes Idle Another Arm Another Trigger Yes No Arm L...

Страница 111: ...er Delay MEASURE Action No Yes Idle Another Arm Another Trigger Yes No Arm Layer Trigger Layer Output Trigger Trigger In Source 0 0 sec No See Note INITiate Yes SOURce ARM DIRection ACCeptor ARM SOURc...

Страница 112: ...ont panel keys can be pressed instead but they may change the setup Remote operation As shown in Figure 7 2 an initiate command is required to take the instrument out of idle The following commands pe...

Страница 113: ...sets to its initial state when the instrument goes back into idle Manual ARM SOURce MANual Event detection for the arm layer is satisfied by pressing the TRIG key The Model 6487 must be in the local m...

Страница 114: ...ass is set to ONCE TRIGger DIRection SOURce operation will loop around the source detector on the initial pass through the arm layer Detection for each subsequent pass is satisfied by an input trigger...

Страница 115: ...igger model Output triggers The Model 6487 can send out an output trigger via the rear panel TRIGGER LINK connector right after the measure action and or when operation leaves the trigger layer An out...

Страница 116: ...item or value is selected by pressing ENTER Use the EXIT key to exit from the menu saving all changes made Table 7 2 Trigger model menu structure Menu Description CONFIG Path to TRIG and ARM menus Ac...

Страница 117: ...46M and 39 992S Set control source to MANual Set control source to TLINK Set TLINK value 1 6 Enable set to ONCE or disable set to NEVER Set control to negative pulse on SOT line Section 8 Set control...

Страница 118: ...g Trigger and request a fresh reading Arm Layer Select control source IMMediate TIMer BUS MANual TLINk PSTest NSTest or BSTest Set measure count 1 to 2048 or INF infinite Set timer interval 0 001 to 9...

Страница 119: ...selected E ARM ILINe NRf and ARM OLINe NRf Input trigger and output trigger cannot share the same trigger link line Defaults set line 1 as the input and line 2 as the output F TRIGger CLEar When this...

Страница 120: ...gure 7 4 Figure 7 4 Trigger link connection operation Input trigger requirements An input trigger is used to satisfy event detection for a trigger model layer that is using the TLINK control source Th...

Страница 121: ...trigger example In a simple test system you may want to close a switching channel and measure the cur rent from a DUT connected to that channel Such a test system is shown in Figure 7 7 This example u...

Страница 122: ...STEP on the switching mainframe to take it out of idle and start the scan The switching mainframes output pulse triggers the Model 6487 to take a reading and store it the Model 6487 then sends an outp...

Страница 123: ...st channel point C D After the relay settles Model 7001 7002 outputs a trigger pulse Since the instrument is programmed to scan 10 channels operation loops back to point B where it waits for an input...

Страница 124: ...ence Manual The trigger applied to Model 7001 7002 from the Model 6487 closes the next channel in the scan which then triggers the Model 6487 to measure that DUT This process continues until all 10 ch...

Страница 125: ...a component handler to perform binning operations Digital I O port Explains how to use the digital I O port to control external circuitry Front panel operation limit tests Explains how to configure a...

Страница 126: ...shows an example where the HI and LO limits for Limit 1 are 2mA and the HI and LO limits for Limit 2 are 1mA A 0mA reading passes both Limit 1 and Limit 2 tests A 1 5mA reading passes Limit 1 but fai...

Страница 127: ...and Limit 2 pass the OK message is displayed The display messages for limit tests are sum marized in Table 8 1 klqb When limit tests are enabled the voltage source value display is not visible but it...

Страница 128: ...esult of the math operation not the input values These math operations are covered in Section 5 Application A typical application for a 2 stage limit test is to sort a batch of DUT according to tolera...

Страница 129: ...e outcome of a test the component handler will place the DUT in the assigned bin Figure 8 4 shows a basic binning system After all programmed testing on the DUT is completed the appropriate digital ou...

Страница 130: ...ent to the component handler for each DUT that is tested Figure 8 5 Operation model for limit testing with binning Pass Start Measure DUT Yes Limit 1 Test No Display L1 Limit 2 Test Pass Display L2 Di...

Страница 131: ...esting pro cess When STest is the selected arm in event for the arm layer of the trigger model the testing process will start when the SOT line is pulled low When STest is the selected arm in event th...

Страница 132: ...lse and category register Category pulse component handler When using this type of handler the Model 6487 pulses one of the four handler lines when a pass or fail condition occurs The handler then pla...

Страница 133: ...mple the required fail pattern by the handler is HI LO HI then you must define the fail pattern of the test to be HI LO HI LO When the test fails the HI LO HI bit pat tern is sent to the handler When...

Страница 134: ...output lines for auto clear Figure 8 7 Digital output auto clear timing example Initially the four digital output lines are cleared in this case they are all set high Limit tests start when the Start...

Страница 135: ...can be used to sort DUT into bins See Binning page 8 5 for details The digital I O of the Model 6487 serves as the interface between the limit tests and the component handler Via the digital input lin...

Страница 136: ...ge from 5V to 33V applied through the external device being driven The high current sink capacity of the output driver allows direct control of relays solenoids and lamps no additional circuitry neede...

Страница 137: ...ed by replacing the relay with the device When the output line is set LO 0V the output transistor sinks current through the external device In the HI state the output transistor is off transistor swit...

Страница 138: ...high output 3 75V When the output line is set LO the transistor turns on transis tor switch closed to route current to digital ground As a result a low logic output 0V is provided at the output If th...

Страница 139: ...d sequence sets output lines 4 and 2 HI and output lines 3 and 1 LO SOUR2 TTL 10 Set output lines 4 and 2 HI SOUR2 TTL Request output pattern value Table 8 2 SCPI commands digital outputs Command Desc...

Страница 140: ...ecimal weight values for the desired HI lines For example to set an output pattern to 0101 lines 3 and 1 HI set the output value to 5 4 1 Limits configuration menu The configuration menu for limits is...

Страница 141: ...andler pulls the SOT line of the Digital I O high BSTEST Test starts when the handler pulls the SOT line of the Digital I O either high or low klqb The other arm in control sources are seldom used wit...

Страница 142: ...ult of Limit 1 test 0 pass or 1 fail C LIMit2 Limit 2 Testing UPPer Configure upper limit DATA n Set limit 9 99999e20 to 9 99999e20 1 0 SOURce2 NDN or NRf Specify 4 bit output fail pattern 15 B LOWer...

Страница 143: ...Specify 4 bit digital output clear pattern 15 B CLEar Clear I O port return output to TTL pattern IMMediate Clear I O port immediately AUTO b Enable or disable auto clear OFF DELay n Specify delay pul...

Страница 144: ...e is used to send decimal values and does not use a header The following examples show the proper parameter syntax to set an output pattern to 1101 lines 4 3 and 1 set HI b1101 Binary format NDN param...

Страница 145: ...M SOURce name Typical start of test options IMMediate Test starts when LIMIT key is pressed NSTest Test starts when component handler pulls the SOT line low PSTest Test starts when component handler p...

Страница 146: ...eration and reference Covers the following GPIB topics GPIB bus standards GPIB bus connections Primary address General IEEE 488 bus commands Front panel GPIB operation Programming syntax RS 232 interf...

Страница 147: ...erface When using the RS 232 interface you must set baud rate data bits parity terminator and flow control For the RS 232 interface you can only use the SCPI language to program the instrument Languag...

Страница 148: ...ettings Primary address 0 30 Language SCPI SCPI 1996 0 which includes 488 2 488 1 or DDC Press the RANGE keys to scroll through ADDress and LANGuage available To make changes to a setting press the cu...

Страница 149: ...ted by the IEEE Institute of Electrical and Electronic Engineers in 1975 The Model 6487 conforms to these standards IEEE 488 1 1987 IEEE 488 2 1992 These standards define a syntax for sending data to...

Страница 150: ...which were silver colored Do not use these types of connectors on the Model 6487 because it is designed for metric threads Figure 9 2 shows a typical connecting scheme for a multi unit test system Fig...

Страница 151: ...nstruction man ual for information about properly connecting to the IEEE 488 bus klqb You can only have 15 devices connected to an IEEE 488 bus including the con troller The maximum cable length is ei...

Страница 152: ...ote operation Generally the instrument should be placed in the remote mode before you attempt to program it over the bus Simply setting REN true does not actually place the instrument in the remote st...

Страница 153: ...into local mode The GTL com mand also restores front panel key operation DCL device clear Use the DCL command to clear the GPIB interface and return it to a known state Note that the DCL command is no...

Страница 154: ...cate the state of the REM line as the instrument must be addressed to listen with REM true before the REM indicator turns on When the instrument is in remote all front panel keys except for the LOCAL...

Страница 155: ...se a parameter The following are some examples SAV NRf Parameter NRf required RST No parameter used DISPlay ENABle b Parameter b required SYSTem PRESet No parameter used Put at least one space between...

Страница 156: ...n NRf number or one of the fol lowing name parameters DEFault MINimum or MAXimum When the DEFault parameter is used the instrument is programmed to the RST default value When the MINimum parameter is...

Страница 157: ...alue Case sensitivity Common commands and SCPI commands are not case sensitive You can use upper or lower case and any case combination Examples RST rst DATA data SYSTem PRESet system preset Long form...

Страница 158: ...on command is simply a three letter acronym preceded by an asterisk The following SCPI commands from the STATus subsystem are used to help explain how command words are structured to formulate program...

Страница 159: ...message If a colon were included the path pointer would reset to the root level and expect a root command Since enab is not a root command an error would occur Command path rules Each new program mes...

Страница 160: ...form versions of commands and parameters 4 Minimize the amount of white space in command strings 5 Keep numeric parameters simple i e 1 vs 1 000e 00 6 Use all uppercase Response messages A response me...

Страница 161: ...e can be sent to the Model 6487 RS 232 interface reference Sending and receiving data The RS 232 interface transfers data using seven or eight data bits and one stop bit Parity selections include none...

Страница 162: ...e two devices to communicate to each other regarding being ready or not ready to receive data The Model 6487 does not support hardware handshaking flow control Software flow control is in the form of...

Страница 163: ...3 Figure 9 4 RS 232 interface connector If your computer uses a DB 25 connector for the RS 232 interface you will need a cable or adapter with a DB 25 connector on one end and a DB 9 connector on the...

Страница 164: ...messages Table 9 3 PC serial port pinout Signal DB 9 pin number DB 25 pin number DCD data carrier detect 1 8 RXD receive data 2 3 TXD transmit data 3 2 DTR data terminal ready 4 20 GND signal ground...

Страница 165: ...er in the status structure Status byte and service request SRQ Explains how to program the status byte to generate service requests SRQs Shows how to use the serial poll sequence to detect SRQs Status...

Страница 166: ...mmed by the user the RQS MSS bit will set to indicate that an SRQ has occurred Status register sets A typical status register set is made up of a condition register an event register and an event enab...

Страница 167: ...ister Logical OR Always Zero Operation Complete Query Error Device Specific Error Execution Error Command Error User Request Power On OPC QYE DDE EXE CME URQ PON ESR ESE NRf ESE MSB MSB 12 13 12 13 Ev...

Страница 168: ...ue CLS STATus QUEue CLEar SYSTem ERRor CLEar Reset all bits of the following event registers to 0 Standard event register Operation event register Measurement event register Questionable event registe...

Страница 169: ...and B1 the binary value would be 11010 where B4 1 B3 1 B1 1 and all other bits are 0 When you use one of the other formats con vert the binary number to its decimal hexadecimal or octal equivalent Bin...

Страница 170: ...cates which bits in the register are set That value if not already binary will have to be converted to its binary equivalent For exam ple for a binary value of 100101 bits B5 B2 and B0 are set The ret...

Страница 171: ...dependent on the summary messages 0 or 1 For example if the standard event register is read its register will clear As a result its summary message will reset to 0 which in turn will reset the ESB bi...

Страница 172: ...the Model 6487 to obtain the status byte a k a serial poll byte B6 is the RQS bit See Serial polling and SRQ page 10 9 for details on using the serial poll sequence When using the STB command Table 1...

Страница 173: ...he first SRQ has not been cleared The serial poll does not clear MSS The MSS bit stays set until all status byte summary bits are reset SPE SPD serial polling The SPE SPD general bus command is used t...

Страница 174: ...ard event status The used bits of the standard event register Figure 10 4 are described as follows Bit B0 operation complete OPC Set bit indicates that all pending selected device operations are compl...

Страница 175: ...the last time this register has been read PON B7 CME B5 EXE B4 DDE B3 QYE B2 B1 OR Standard Event Register Standard Event Enable Register PON Power On URQ User Request CME Command Error EXE Execution...

Страница 176: ...indicates that the Model 6487 is in the arm layer waiting for an arm event to occur Bit B10 idle state Idle Set bit indicates the Model 6487 is in the idle state Figure 10 5 Operation event status OR...

Страница 177: ...ervoltage Logical AND OR Logical OR B0 128 27 32 25 16 24 8 23 4 22 2 21 Decimal Weights RAV B6 EVENt 64 26 BFL B9 BAV B8 LL1F B1 ROF B7 LP B5 HL2F B4 LL2F B3 HL1F B2 Measurement Condition Register B0...

Страница 178: ...t when a voltage sweep has been completed Section 6 and if the programmed number of A V ohms cycles have been taken Section 3 Bit B10 input overvoltage IOV Set bit indicates there is an input over vol...

Страница 179: ...e condition registers are listed in Table 10 4 For details on read ing registers see Reading registers page 10 6 Table 10 4 Common and SCPI commands condition registers Command Description STATus OPER...

Страница 180: ...e corresponding enable bit is set as programmed by the user the output summary of the register will set to 1 which in turn sets the summary bit of the status byte register The commands to program and...

Страница 181: ...gure 10 1 shows how the two queues are structured with the other registers Table 10 6 Common and SCPI commands event enable registers Command Description ESE NDN or NRf ESE STATus OPERation ENABle NDN...

Страница 182: ...the output queue When data is placed in the output queue the message available MAV bit in the status byte register sets A data message is cleared from the output queue when it is read The output queu...

Страница 183: ...queue are preceded by a code number Negative numbers are used for SCPI defined messages and positive numbers are used for Keithley defined messages The messages are listed in Appendix B As shown in T...

Страница 184: ...messages for error queue Read the enabled messages Specify messages not to be placed in queue Read the disabled messages Clear messages from error queue SYSTem subsystem Read error queue Read and cle...

Страница 185: ...11 CommonCommands Common commands This section lists and describes the common commands...

Страница 186: ...te command Set the operation complete bit in the standard event register after all pending commands have been executed B OPC Operation complete query Places an ASCII 1 into the output queue when all p...

Страница 187: ...ut queue after all pending command operations are complete Typically either one of these commands is sent after the INITiate command The INITiate command is used to take the instrument out of idle in...

Страница 188: ...defaults When the RST command is sent the Model 6487 performs the following operations 1 Returns Model 6487 to the RST default conditions see Default column of SCPI tables 2 Cancels all pending comman...

Страница 189: ...ontinue Wait until previous commands are completed Effectively the WAI command is a No Op no operation for the Model 6487 and thus does not need to be used Two types of device commands exist Sequentia...

Страница 190: ...12 SCPISignalOriented MeasurementCommands...

Страница 191: ...ation returns to the idle state When this command is executed the Model 6487 will be configured as follows The specified function is selected All controls related to the selected function are defaulte...

Страница 192: ...READ or MEASure command is sent C READ Trigger measurement s and request reading s This command is used to trigger and acquire readings The number of readings depends on how the trigger model is conf...

Страница 193: ...a one shot measurement and acquire the reading When this command is sent the following commands execute in the order that they are presented CONFigure function READ When CONFigure is executed the inst...

Страница 194: ...Play subsystem Covers the SCPI commands that are used to control the display FORMat subsystem Covers the SCPI commands to configure the format that readings are sent over the bus SYSTem subsystem Cove...

Страница 195: ...e to enable the display pressing the LOCAL key or cycling power Table 13 1 SCPI commands display Command Description Default Ref DISPlay DIGits n DIGits ENABle b ENABle WINDow 1 TEXT DATA a DATA STATe...

Страница 196: ...gram message or the last command in the program message If you include a command after an indefinite block message on the same line it will be treated as part of the message and is displayed instead o...

Страница 197: ...y Model 6487 Table 13 2 SCPI commands data format Command Description Default Ref FORMat DATA type length Specify data format ASCii REAL 32 or SREal ASCii A DATA Query data format ELEMents item list S...

Страница 198: ...ASCII data format is in a direct readable form for the operator Most programming languages easily convert ASCII mantissa and exponent to other formats However some speed is compromised to accommodate...

Страница 199: ...lk Model 6487 until after the data is read input to the computer Also to avoid erratic operation the readings of the data string and terminator should be acquired in one piece The header 0 can be read...

Страница 200: ...ms function OHMS will be returned Voltage source This element returns the programmed voltage source value in volts when the voltage source is in operate Zero will be returned when the voltage source o...

Страница 201: ...l REL and the AVG filter enabled The reading was taken 223 6299 seconds after the instrument was turned on The voltage source was on and set to 123 45V C FORMat BORDer name Parameters NORMal Normal by...

Страница 202: ...ESet defaults Select power line frequency 50 or 60 Hz Query power line frequency Path to control auto line frequency selection Turn automatic line frequency ON or OFF Query automatic line frequency st...

Страница 203: ...in the SCPI tables in the Section 14 A setup is saved in memory using the SAV command See Section 11 Common Commands for details Command Description Default Ref SYSTem CLEar KEY NRf KEY LOCal REMote R...

Страница 204: ...arrow key 31 DAMP key 16 SOURCE down arrow key 32 EXIT key This command is used to simulate front panel key presses For example send the follow ing command to simulate pressing the MATH key SYSTem KE...

Страница 205: ...Table 14 3 FORMat command summary Table 14 4 SENSe command summary Table 14 5 SOURce command summary Table 14 6 STATus command summary Table 14 7 SYSTem command summary Table 14 8 TRACe command summar...

Страница 206: ...on for that command or command subsystem SCPI A checkmark indicates that the command and its parameters are SCPI confirmed An unmarked command indicates that it is a SCPI command but does not conform...

Страница 207: ...nput path for limit testing CALCulate 1 or SENSe 1 SENS FEED Query input path for limit tests LIMit 1 Limit 1 Testing UPPer Configure upper limit DATA n Set limit 9 99999e20 to 9 99999e20 1 0 DATA Que...

Страница 208: ...r limit SOURce2 NDN or NRf Specify 4 bit I O fail pattern 0 to 15 15 see note SOURce2 Query output pattern value STATe b Enable or disable limit 2 test OFF STATe Query state of limit 2 test FAIL Retur...

Страница 209: ...20 0 0 OFFSet Query Rel value STATe b Enable or disable Rel OFF STATe Query state of Rel CALCulate3 Path to configure and control CALC3 calculations on buffer data 6 FORMat name Select buffer statisti...

Страница 210: ...2 DATA a Define ASCII message a up to 12 characters DATA Read text message STATe b Enable or disable text message mode Note 3 STATe Query state of text message mode Notes 1 RST and SYSTem PRESet have...

Страница 211: ...atus registers ASCii HEXadecimal OCTal or BINary ASC SREGister Query format for reading event registers SOURce2 name Select data format for reading output patterns ASCii HEXadecimal OCTal or BINary AS...

Страница 212: ...ter 4 TCONtrol name Select filter control MOVing or REPeat MOV TCONtrol Query filter control COUNt n Specify filter count 2 to 100 10 COUNt Query filter count STATe b Enable or disable digital filter...

Страница 213: ...time interval for each phase POINts Query number of points ONEShot b Enable or disable one shot mode ON ONEShot Query state of one shot mode CYCLes NRf Set number of A V cycles 1 to 9999 3 CYCLes Quer...

Страница 214: ...e set above voltage source range 2 Default for DDC mode see Appendix C is 50V 3 Limit settings are 25 A 250 A 2 5mA and 25mA current limit will be set to closest programmed value For the 500V and the...

Страница 215: ...9s 1s DELay Query delay INITiate Arm sweep put source in operate ABORt Abort sweep put source in standby STATe Query if sweep running 1 sweep in progress SOURce2 Path to control Digital I O port 8 TTL...

Страница 216: ...0 to 60 sec 0 0001 DELay Query delay value TTL4 Line 4 mode configuration MODE name Select output line 4 mode EOTest or BUSY EOT MODE Query line 4 mode BSTate b Select active TTL level for busy 1 ON...

Страница 217: ...ogram the enable register Note 3 ENABle Read the enable register CONDition Read the condition register PRESet Return status registers to default states QUEue Read error queue NEXT Read and clear oldes...

Страница 218: ...s 1 Commands in this subsystem are not affected by RST or SYSTem PRESet The effects of cycling power CLS and STATus PRESet are explained by the following notes 2 Event registers Power up and CLS clear...

Страница 219: ...ath to control auto frequency STATe b Enable or disable auto frequency ON STATe Query state of auto frequency AZERo Path to control autozero 3 STATe b Enable or disable autozero ON STATe Query state o...

Страница 220: ...t pressed key RS 232 interface 9 LOCal While in LLO removes the LLO and places the Model 6487 in local RS 232 only REMote Places the Model 6487 in remote if not in LLO RS 232 only RWLock Places the Mo...

Страница 221: ...of buffer 1 to 3000 100 ACTual Query number of readings stored in buffer POINts Query buffer size FEED name Select source of readings for buffer SENSe 1 CALCulate 1 or CALCulate2 SENS1 CONTrol name S...

Страница 222: ...m control source COUNt n Set measure count 1 to 2048 or INF infinite 11 COUNt Query measure count TIMer n Set timer interval 0 001 to 99999 999 sec 0 100 TIMer Query timer interval TCONfigure DIRectio...

Страница 223: ...uto delay OFF AUTO Query state of auto delay DELay Query delay value TCONfigure DIRection name Enable SOURce or disable ACCeptor bypass ACC DIRection Query trigger source bypass ASYNchronous Configure...

Страница 224: ...ing calibrator voltages when testing the 2nA to 2 A ranges Performing the verification test procedures Summarizes test considerations and describes how to restore factory defaults Offset voltage calib...

Страница 225: ...cedures may expose you to hazardous voltages which could cause personal injury or death if contacted Use standard safety precautions when working with hazardous voltages klqb If the instrument is stil...

Страница 226: ...487 requires a line voltage of 100 to 120V or 220 to 240V at a line frequency of 50 to 60Hz Verification tests must be performed within this range Be sure the line volt age setting agrees with the exp...

Страница 227: ...tal Multimeter Keithley Model 2001 DC Voltage 3 10V 32ppm 50V 50ppm 500V 53ppm Low noise triax cable Low noise coax cable Triax shielding cap Triax to BNC adapter Dual banana to BNC adapter Banana plu...

Страница 228: ...A input value Using the Model 6487 20mA range accuracy specifica tion of 0 1 of reading 1 A the calculated reading limits are Reading limits 20mA 20mA 0 1 1 A 20mA 0 02mA 0 001mA 20mA 0 021mA 19 979mA...

Страница 229: ...gh a scanner multiplexer or other switching equipment t okfkd The maximum safe voltage between the voltage source or ammeter and chassis ground common mode voltage is 505V DC Exceeding this voltage ca...

Страница 230: ...ange accuracy 1 With the power off connect the current calibrator to the Model 6487 INPUT jack Figure 15 1 Use the appropriate coax cable triax to BNC adapter and BNC to dual banana plug adapter where...

Страница 231: ...tput is turned on 6 Enable the Model 6487 REL mode Leave REL enabled for the remainder of the test Table 15 2 Reading limits for 20 A to 20mA ranges Model 6487 Range Calibrator Current Model 6487 Curr...

Страница 232: ...le 8 Repeat the procedure for negative source currents with the same magnitudes as those listed in Table 15 3 Table 15 3 Reading limits for 2nA to 2 A ranges Model 6487 range Nominal calibrator voltag...

Страница 233: ...3 Be sure to observe polarity HI to HI LO to LO 2 Turn on the DMM and Model 6487 allow them to warm up for one hour 3 Select the DMM DCV function and enable autoranging 4 Temporarily short the ends of...

Страница 234: ...e accuracy Model 6487 Source Range Output Voltage Model 6487 Output Voltage Limits 1 Year 18 C 28 C 10V 10 000V 9 989 to 10 011V 50V 50 000V 49 946 to 50 054V 500V 500 00V 499 21 to 500 79V NEXT PREV...

Страница 235: ...ibration Calibration menu Discusses calibration menu items Aborting calibration Describes how to halt the calibration procedure at any time Current calculations Details how to calculate currents from...

Страница 236: ...ture of 22 to 24 C with relative humidity of less than 70 unless otherwise noted Warm up period Allow the Model 6487 to warm up for at least one hour before performing calibration If the instrument ha...

Страница 237: ...imum continuous input voltage is 505V DC Exceeding this value may cause instrument damage Calibration cycle Perform verification at least once a year to ensure the unit meets or exceeds its specifica...

Страница 238: ...A 550ppm 200 A 100ppm 2mA 55ppm 20mA 55ppm Electrometer Calibration Standard Keithley Model 5156 Nominal Resistance 2 100M 200ppm 1G 300ppm Digital Multimeter Keithley Model 2001 DC Voltage 3 10V 32pp...

Страница 239: ...through these selections Table 16 2 Current test uncertainty ratios with recommended equipment Range 5700 5156 Test uncertainty ratio 2nA 7ppm 300ppm 13 0 20nA 7ppm 200ppm 19 3 200nA 5ppm 200ppm 9 8...

Страница 240: ...ual standard resistor value For example assume you are calibrating the 20nA range using a 2V calibrator voltage with an actual 100 5M standard resistor value The actual calibration current is 2V 100 5...

Страница 241: ...e instrument will prompt for the calibration code CODE 000000 5 Enter the present calibration code on the display Factory default 006487 Use the up and down RANGE keys to select the letter or number a...

Страница 242: ...el 6487 INPUT jack Figure 16 1 Use the coax cable and two adapters where shown 7 Press ENTER The unit will prompt for the positive full scale current 20 00000 A 8 Set the calibrator current to 20 0000...

Страница 243: ...A 0 A 20 00000 A 20 00000 A 200 A 0 A 200 0000 A 200 0000 A 2mA 0mA 2 000000mA 2 000000mA 20mA 0mA 20 00000mA 20 00000mA Calibrate zero positive full scale and negative full scale for each range Triax...

Страница 244: ...just the Model 6487 display to agree with the calculated current then press ENTER 9 The Model 6487 will prompt for the negative full scale calibration point 2NA CAL 10 Press ENTER The instrument will...

Страница 245: ...tual standard resistor value I V R Calibrate zero positive full scale and negative full scale for each range INPUT Triax Cable Connect Calibrator to 100M or 1G Resistor Link Shield and Chassis 120 LIN...

Страница 246: ...and the instrument will prompt for the negative full scale calibration voltage 10 00000 V 7 Note the DMM voltage reading Adjust the Model 6487 display to agree with that voltage and then press ENTER...

Страница 247: ...e calibration summary Model 6487 Range Calibration Voltages 10V 10 00000V 0 00000V 10 0000V 50V 50 00000V 0 00000V 50 00000V 500V 500 0000V 0 00000V 500 0000V Nominal values Adjust display to agree wi...

Страница 248: ...the calibration code Follow the steps below to change the calibration code 1 Press MENU select CAL then press ENTER The instrument will display the following CAL VOFFSET 2 Use the up or down RANGE key...

Страница 249: ...the following CAL VOFFSET 2 Use either RANGE key to select CAL DATES then press ENTER The Model 6487 will display the last calibration date for example DATE 11 15 02 3 Press ENTER to view the calibrat...

Страница 250: ...ance Setting line voltage and replacing line fuse Describes how to set the line volt age properly and replace the line fuse with the correct rating Front panel tests Covers testing the front panel key...

Страница 251: ...the fuse holder assembly Figure 17 1 Gently push in and to the left Release pressure on the assembly and its internal spring will push it out of the power module 2 Remove the fuse and replace it with...

Страница 252: ...RANGE keys and press ENTER Table 17 2 Front panel tests Test Description DISP Test display KEY Test front panel keys 120 LINE RATING 50 60Hz 50 VA MAX INPUT CHANGE IEEE ADDRESS WITH FRONT PANEL MENU...

Страница 253: ...ayed The 12 digits and annunciators are sequentially displayed The annunciators located at either end of the display are sequentially displayed 4 When finished abort the display test by pressing EXIT...

Страница 254: ...A Specifications...

Страница 255: ...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...

Страница 256: ...B StatusandErrorMessages...

Страница 257: ...l memory lost Self test failed Configuration memory lost Program syntax error Program currently running Illegal program name Cannot create program Expression error Hardware missing Data corrupt or sta...

Страница 258: ...large Invalid character in number Numeric data error Header suffix out of range Undefined header Program mnemonic too long Header separator error Command header error Missing parameter Parameter not a...

Страница 259: ...ation Command warning Calibration errors Date of calibration not set Next date of calibration not set Calibration data invalid Measurement offset data invalid Measurement gain data invalid Not permitt...

Страница 260: ...be deleted Not an operator or number Mismatched parentheses Not a number of data handle Mismatched brackets Too many parentheses Entire expression not parsed Unknown token Error parsing mantissa Error...

Страница 261: ...ley 6487 Serial Poll Byte Events DDC Ready DDC Reading Done DDC Buffer Full DDC Reading overflow SE SE SE EE EE EE EE EE SE EE EE SE SE SE SE EE error event SE status event SYS system error event NOTE...

Страница 262: ...ame Blanks spaces within the command name For example SYST ERR Incorrect space between SYST and ERR SYST ERR Correct 410 Query INTERRUPTED This error occurs when you have sent a valid query to the ins...

Страница 263: ...nerates an error 113 Undefined header and then addressing the instrument to talk will generate an error 420 Query UNTERMI NATED as well Valid query following an invalid command This situation can occu...

Страница 264: ...C DDCEmulationCommands...

Страница 265: ...d cannot be used Be sure to refer to the notes at the end of the table for information on command restrictions rqflk The DDC language is intended to be used only over the IEEE 488 bus Using front pane...

Страница 266: ...3456E 02 SCPI not available See FORMat subsystem X G1 ASCII readings without prefix 1 23456E 02 G2 ASCII readings with prefix and buffer suffix if in B1 or B2 NDCA 1 23456E 02 012 G3 ASCII readings wi...

Страница 267: ...RCE down key H17 Hit MENU key H18 Hit COMM key H19 Hit DISP key H20 Hit TRIG key H21 Hit LIMIT key H22 Hit DIGITS key H23 Hit RATE key H24 Hit cursor left key H26 Hit SAVE key H27 Hit SETUP key H28 Hi...

Страница 268: ...lt conditions SAV 0 L2 Return to saved defaults RCL 0 L3 L6 Calibration commands not supported G SRQ SRQ Mask Bits H M0 Clears SRQ mask SRQ disabled SRE 0 None X M1 Reading Overflow STATus MEASurement...

Страница 269: ...d analog filters K X Interval Q0 175msec TRIGger DELay 0 175 X Q1 Set to n seconds n 0 01msec to 999 999sec TRIGger DELay NRf L Range R0 Enable autorange SENSe 1 RANGe AUTO ON X R1 2nA range SENSe 1 R...

Страница 270: ...IMMediate T3 One shot triggered by GET ARM SEQuence 1 SOURce BUS ARM SEQuence 1 COUNt INF TRIGger SEQuence 1 COUNt 1 INIT IMMediate T4 Continuous triggered by X SCPI Not Available T5 One shot triggere...

Страница 271: ...rce value SOURce 1 VOLtage U9 Send voltage source status word See Figure C 3 Voltage Source Vn r l Voltage source value range current limit n 505 to 505 SOURce 1 VOLTage NRf r 0 50V range 1 500V range...

Страница 272: ...Correct value after going to the desired range Also unlike the 487 Zero Correct values are not saved across power cycles and must be re acquired after power cycling the unit C G6 and G7 are not suppor...

Страница 273: ...set in the status byte serial poll J Buffer operating notes a The 6487 does not support a continuous wrap around buffer Therefore the N0 command will simply stop storage and clear the buffer b Nx x 1...

Страница 274: ...A V ohms in DDC mode Sweeps or A V ohms are not allowed in the DDC mode A SCPI ONLY message will be displayed if you attempt to use sweeps or A V ohms from the front panel Status words The U0 U2 and...

Страница 275: ...PLAY INTENSITY 0 Normal 1 Dim Characters 2 Off ZERO CHECK 0 Disabled 1 Enabled V I OHMS 0 Disabled 1 Enabled DATA FORMAT 0 Rdg with prefix ASCII 1 Rdg without prefix ASCII 2 Rdg buffer location with p...

Страница 276: ...read when no SRQ was generated by the Model 6487 bit 6 is clear the current status of the instrument will be read For example if a reading was done bit 3 would be set SRQ is enabled by setting the cor...

Страница 277: ...ming data store Reading Done B3 Set when the instrument has completed the present conversion and is ready to take another reading Cleared when the reading has been sent Ready B4 Set when the instrumen...

Страница 278: ...ead to clear the SRQ line Otherwise the instrument will continuously assert SRQ Figure C 4 Status byte format Table C 2 Status byte and SRQ mask interpretation Bit Decimal Weighting Description 0 LSB...

Страница 279: ...r Bus lines This section describes the operation of data lines bus management lines and handshake lines Bus commands This section describes the purpose of bus commands lists the three catagories of bu...

Страница 280: ...ntroller Each listener is then referred to as an active listener Devices that do not need to listen are instructed to unlisten The reason for the unlisten instruction is to optimize the speed of bus i...

Страница 281: ...is limited to 15 devices including the controller Thus any number of talkers and listeners up to that limit may be present on the bus at one time Although sev eral devices may be commanded to listen s...

Страница 282: ...e that proper data transfer and operation takes place Each bus line is active low with approximately zero volts represent ing a logic 1 true The following paragraphs describe the operation of these li...

Страница 283: ...ensures reliable data transmission regardless of the transfer rate Generally data transfer will occur at a rate determined by the slowest active device on the bus One of the three handshake lines is c...

Страница 284: ...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 paragraphs Figure D 2 IEEE 488 hand...

Страница 285: ...Selective Device Clear GTL Go To Local UNL Unlisten UNT Untalk X X X Low X Low Low Low Low Low Low Low Low High High Set up devices for remote operation Marks end of transmission Clears interface Defi...

Страница 286: ...HT LF VT FF CR SO SI GTL SDC PPC GET TCT DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US LLO DCL PPU SPE SPD SP 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 16 17 18 19 20 21...

Страница 287: ...erface Clear IFC is used to clear the interface and return all devices to the talker and listener idle states ATN Attention The controller sends ATN while transmitting addresses or multiline commands...

Страница 288: ...ion for example take a reading Although GET is an addressed command many devices respond to GET without addressing Address commands Addressed commands include two primary command groups and a secondar...

Страница 289: ...re based on the instrument model defined by the Standard Commands for Programmable Instruments SCPI Consor tium s SCPI standard Generally these commands are sent as one or more ASCII characters that t...

Страница 290: ...eners are present Note that ATN is true for both the listen command and the SDC command byte itself Table D 5 gives a typical common command sequence In this instance ATN is true while the instrument...

Страница 291: ...A VALID UNIVERSAL COMMAND GROUP ATN ATTENTION DCL DEVICE CLEAR IFC INTERFACE CLEAR REN REMOTE ENABLE SPD SERIAL POLL DISABLE SPE SERIAL POLL ENABLE ADDRESS COMMAND GROUP LISTEN TALK LAG LISTEN ADDRESS...

Страница 292: ...T5 exist only after the instrument has been addressed to talk L Listener Function The ability for the instrument to receive device dependent data over the bus from other devices is provided by the L...

Страница 293: ...5 E Bus Driver Type The instrument has open collector bus drivers E1 TE Extended Talker Function The instrument does not have extended talker capa bilities TE0 LE Extended Listener Function The instru...

Страница 294: ...1 Protocol This section introduces the GPIB 488 1 protocol Selecting the 488 1 protocol This section describes how to select the 488 1 protocol Protocol differences This section covers the differences...

Страница 295: ...when valid address is entered Power On Setup Conditions Message Exchange Options Input buffer size Queries that return more than one response message unit Queries that generate a response when parsed...

Страница 296: ...ed in this appendix 15 16 17 18 19 20 21 22 23 Macro information Response to IDN identification Storage area for PUD and PUD Resource description for RDT and RDT Effects of RST RCL and SAV TST informa...

Страница 297: ...s the right cursor key to place the cursor on the currently selected language either DDC SCPI or 488 1 will be flashing 5 Scroll using a RANGE key until 488 1 is displayed To change back to 488 2 scro...

Страница 298: ...wing command strings are invalid CURR RANG 020 OPC CURR RANG READ READ READ The following strings are valid curr nplc 1 0 curr rang min CURR RANG MAX READ When a query is sent either the data must be...

Страница 299: ...acquired This immediate release of bus hold off is done to support GET SDC IFC TRG RCL RST SYSTem PRESet and ABORt during data acquisition NDAC hold off NDAC hold off is included with the GPIB 488 1...

Страница 300: ...byte will be set when the query is fin ished being processed not when there is data available in the output buffer as with the SCPI protocol For the 488 1 protocol output data will not be formatted u...

Страница 301: ...cle status Clear buffer CALL send addr trig coun 200 status 200 trigger count CALL send addr trac poin 200 status Set buffer size to 200 CALL send addr trac feed cont next status Enable buffer CALL s...

Страница 302: ...ration Calibration commands Summarizes those commands necessary to calibrate the Model 6487 by remote Remote calibration overview Gives an overview of the basic procedure for calibrating the Model 648...

Страница 303: ...Ource Voltage source calibration commands NFSCale Turn on source set it to negative full scale for present source range NFSValue NRf Calibrate negative full scale using DMM reading ZERO Set source out...

Страница 304: ...libration point for the selected function and range For exam ple send the following commands for the 20mA range CAL PROT SENS 0 CAL PROT SENS 2e 2 CAL PROT SENS 2e 2 5 Repeat steps 3 and 4 for each ra...

Страница 305: ...e 6 CAL PROT SENS 0 CAL PROT SENS 2e 6 CAL PROT SENS 2e 6 20 A SENS CURR RANG 2e 5 CAL PROT SENS 0 CAL PROT SENS 2e 5 CAL PROT SENS 2e 5 200 A SENS CURR RANG 2e 4 CAL PROT SENS 0 CAL PROT SENS 2e 4 CA...

Страница 306: ...V SOUR1 VOLT RANG 50 CAL PROT VSO NFSC CAL PROT VSO NFSV DMM_Reading CAL PROT VSO ZERO CAL PROT VSO ZVAL DMM_Reading CAL PROT VSO PFSC CAL PROT VSO PFSV DMM_Reading 500V SOUR1 VOLT RANG 500 CAL PROT V...

Страница 307: ...urce impedance Electrostatic interference and shield ing and Making connections Applications Covers applications to measure Diode leakage current Capacitor leakage current Measuring high resistance Ca...

Страница 308: ...ments circuit and nearby sources These currents can considerably degrade the accuracy of low current measurements Some ways to reduce leakage currents are to use good quality insulators maintain clean...

Страница 309: ...as the bottom The voltage difference is equal to the voltage burden of the picoammeter Since the top and the bottom of the insulator are at nearly the same poten tial no significant current will flow...

Страница 310: ...pecifications Voltage burden may be reduced by performing the voltage offset correction procedure Voltage offset correction procedure klqb To maintain specified operation any time there is a substanti...

Страница 311: ...se voltage Finally RF and CF are the feedback resistance and capacitance respectively The source noise gain of the circuit can be given by the following equation Note that as RS decreases in value the...

Страница 312: ...the simplified picoam meter model in Figure G 3 The elements of interest for this discussion are the source capacitance CS and the feedback capacitance CF Taking into account the capacitive reactance...

Страница 313: ...ling or interference occurs when an electrically charged object is brought near an uncharged object At low impedance levels the effect of the interference are not noticeable because the charge dissipa...

Страница 314: ...of 0 01pF second a 10 fluctuation a current of 1pA will be generated To reduce the effects of the fields a shield can be built to enclose the circuit being mea sured The easiest type of shield to mak...

Страница 315: ...l shield Figure G 6 With this shield in place the noise current generated by the electrostatic voltage source and the coupling capaci tance flows through the shield to ground rather than through the s...

Страница 316: ...an added low impedance conductor maintained at the same potential as the high impedance circuit which will intercept any interfering voltage or current A guard does not necessarily pro vide shielding...

Страница 317: ...urrent source This circuit is con nected properly so this current does not flow through the picoammeter and therefore does not cause any measurement errors Figure G 8 Proper connection However when th...

Страница 318: ...ctors to use when making picoammeter measurements Typical range change transients During a range change a picoammeter cannot perfectly maintain its voltage burden speci fication When a range change oc...

Страница 319: ...n internal resistance This internal resistance varies as the range is changed For example manually up ranging from 2 A to the 20 A range can never deliver more than 10V 50k 200 A to the DUT This curre...

Страница 320: ...ltage are reduced for lower current ranges The current limit imposed by the RF is also greatly reduced The polarity depends on the polar ity of the input current Figure G 11 was measured with a positi...

Страница 321: ...nge from 20 A to 2 A with a 2 A input current The vast difference from the previous figures in voltage scale and time scale should be noted Note also that the current limiting resistor will be that of...

Страница 322: ...e range change transients can be reduced significantly compared to up ranging transients Using protection circuitry Using protection circuitry can greatly reduce currents and voltages presented to dev...

Страница 323: ...e is not as large but similar in duration As with range change transients the zero check tran sient is presented through an internal impedance which will limit the resulting current through the DUT Ta...

Страница 324: ...ample program the voltage source to sweep voltage from 1 to 10V in 1V steps The Model 6487 performs a current measurement on each voltage step To ensure that the voltage is settled before each current...

Страница 325: ...can be significantly smaller Also damping may help to reduce noise see Damping page 4 8 For this test a fixed bias voltage is to be applied to the capacitor for a specified time to allow the capacitor...

Страница 326: ...sistance The LO terminal of the picoammeter is connected to the LO terminal of the voltage source Both LO terminals are also connected to earth ground This should be done via the ground link on the re...

Страница 327: ...tance to the picoammeter For this test a fixed bias voltage is applied across the insulator for a specified time to allow the charging effects of cable capacitance to stabilize The current is then mea...

Страница 328: ...est pattern for a specified time typically one second to polarize the test pattern The test voltage typically 100V is then applied and after a specified time typically one second the Model 6487 measur...

Страница 329: ...ide leakage current readings forced by the bias voltage source As an alternative one or more Model 6487s could be switched through a switching mainframe and matrix switch card arrangement to take curr...

Страница 330: ...l darkness Avalanche diodes respond as shown by the solid line in Figure G 21 Notice the small irregularity of the curve while sweeping around 10 12V This irregularity is made larger under additional...

Страница 331: ...ic sputtering or milling The magnitude of the beam current determines what type of operation is per formed A low beam current results in very little material being sputtered and is therefore ideal for...

Страница 332: ...Model 6487 is ideal for this application because it offers a wide selection of range set tings spanning from 20mA to 2nA This will result in 5 1 2 digit resolution ranging from 100nA to 10fA Numerous...

Страница 333: ...librator 15 4 16 4 Calibrator voltage calculations 15 5 Capacitor leakage current G 19 Case sensitivity 9 12 Category 8 8 8 9 Changing the calibration code 16 14 cleaning test fixtures 2 10 tips 2 10...

Страница 334: ...g 2 12 Floating measurements 2 12 Flow control RS 232 signal handshaking 9 17 Focused ion beam applications G 25 Focused Ion Beam signal connections G 26 FORMat command summary 14 7 FORMat subsystem 1...

Страница 335: ...nce Using the 6487 G 20 Measuring high resistance with external bias source G 19 Median filter 4 9 Menu 1 12 16 5 Model 6487 interface function codes D 14 Multiple command messages 9 14 Multiple respo...

Страница 336: ...15 SCPI commands D 11 amps function 3 10 3 14 autozero 3 4 buffer 6 5 6 13 reset registers and clear queues 10 4 system 13 9 triggering 7 10 SCPI errors eliminating B 7 SCPI language 9 2 SCPI programm...

Страница 337: ...17 Triax 2 2 Trigger 7 5 TRIGger command summary 14 18 Trigger delay 7 6 Trigger Mode C 7 Trigger model configuration 7 8 menu structure 7 8 Triggering 7 1 Typical addressed command sequence D 12 Typ...

Страница 338: ...ll other trademarks and trade names are the property of their respective companies 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 Keithley Instruments Inc Corporate Headquarters 28775 Aurora Ro...

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