User's Manual

Verification and Calibration Appendix B
Series N5700 User’s Guide 99
Constant Current Tests
NOTE
Refer to the appropriate test record form for the instrument settings of the
model you are checking.
Current Programming and Readback Accuracy
Test category = performance, calibration
This test verifies that the current programming and measurement
functions are within specifications.
1 Turn off the power supply and connect the current shunt directly
across the output. Connect the DVM across the current shunt.
2 Turn on the power supply and program the output voltage to its
full-scale value and the output current to zero. The CC
annunciator should be on and the output voltage reading should
be approximately zero.
3 Divide the voltage drop (DVM reading) across the current shunt
by its resistance to convert to amps and record this value (Iout).
Also record the current reading on the front panel display. The
readings should be within the limits specified in the test record
card for the appropriate model under Current Programming and
Readback, Minimum Current Iout.
4 Program the output current to its full-scale rating.
5 Divide the voltage drop (DVM reading) across the current shunt
by its resistance to convert to amps and record this value (Iout).
Also record the current reading on the front panel display. The
readings should be within the limits specified in the test record
card for the appropriate model under Current Programming and
Readback, High Current Iout.
CC Load Effect
Test category = performance
This test measures the change in output current resulting from a
change in output voltage from full scale to short circuit.
1 Turn off the power supply and connect the current shunt, DVM,
and electronic load as shown in figure B. Connect the DVM
directly across the current shunt.
2 To ensure that the values read during this test are not the
instantaneous measurement of the AC peaks of the output
current ripple, several DC measurements should be made and
averaged. If you are using an Agilent 3458A, you can set up the
voltmeter to do this automatically. From the instrument’s front
panel, program 100 power line cycles per measurement. Press
NPLC 100 ENTER.
3 Turn on the power supply and program the output current to its
full-scale value and the output voltage to its maximum
programmable value (Vmax).