Keithley 2651A Reference Manual page 710

Appendix B: Calibration
6. Turn the output off and change connections as shown in
range and above)
7. Select the DMM volts function.
8. Repeat steps 4 through 6 for the 1 A, 5 A, 10 A, and 20 A ranges; and for the 20 A DC level on
the 50 A range. Calculate the current from the DMM voltage reading and characterized 0.1 Ω
resistance value: I=V/R
9. Verification of a pulsed output (levels greater than 20 A on the 50 A range) is accomplished with
the same techniques and characterized 0.1 Ω resistor (shunt) as used for other 1 A and above
ranges. However, there is an additional requirement that the external DMM must be capable of
synchronizing to and measuring the short duration shunt voltage pulse with the required
precision.
10. The -45 A high speed ADC pulse verification script
setting up a single 1 ms pulse on the 50 A range and measuring the last 500 μs of the pulse using
the Model 2651A instrument's fast ADC. The script also sets up a trigger signal that will appear
on the rear panel digital I/O connector and be synchronized to the start of the fast ADC
measurement (500 μs after the start of the pulse). The external DMM must be able to complete its
measurement of the shunt voltage within 500 μs of receiving this trigger signal.
B-10
Model 2651A High Power System SourceMeter® Instrument Reference Manual
(on page B-8).
Connections for current verification (1 A
(on page B-11) provides an example for
2651A-901-01 Rev. A / March 2011