Keithley 6430 Instruction Manual page 470

19-20 Calibration
9.
10.
11.
12.
13.
14.
Table 19-5
Standard resistance values for 1pA-100nA gain calibration
Range
100nA
010nA
001nA
100pA
010pA
001pA
1
Nominal Model 5156 values. Use actual value when calculating current.
2
Nominal values. Use actual DMM reading and resistance to calculate current: I = V/R
Step 4: Offset calibration
1.
2.
3.
4.
Press ENTER. The unit will prompt you for the calculated current:
DMM RDG: +085.0000nA
Use , ▲, ▼, , ENTER or EXIT.
Calculate the current from the DMM voltage reading and resistance value, then adjust
the Model 6430 display to agree with the calculated current, and press ENTER.
The unit will once again prompt you as follows:
I-CAL
Press ENTER to Output +085.00nA
Press ENTER. The unit will prompt you for the calculated current:
DMM RDG: +085.0000nA
Use , ▲, ▼, , ENTER or EXIT.
Calculate the current, then adjust the Model 6430 display to agree with that value, and
press ENTER.
Repeat steps 4 through 13 for the 10nA - 1pA ranges using the standard resistance val-
ues summarized in Table 19-5.
Standard resistance
100MΩ
001GΩ
010GΩ
100GΩ
100GΩ
100GΩ
Disconnect all cables and test leads connected to the Remote PreAmp or mainframe.
However, leave the Remote PreAmp connected to the mainframe REMOTE PreAmp
connector.
Place the triax shielding cap on the Remote PreAmp FORCE jack.
Select OFFSET in the calibration menu, then press ENTER. The unit will display the
following:
PREAMP OFFSET CAL
ALL BYPASS 10uA 1uA 100nA
Select ALL, then press ENTER to calibrate all ranges and the bypass mode. During this
process, the instrument will display the range being calibration. For example:
PREAMP OFFSET CAL
Now calibrating 1 pA Range....
1 2
DMM reading
008.5V
008.5V
008.5V
008.5V
850mV
008.5mV
2
Calibration current
85nA
08.5nA
00.85nA
85pA
08.5pA
00.85pA