Appendix Service Information
Constant Current (CC) Verifications
174
Constant Current (CC) Verifications
Constant Current Test Setup
Follow the general setup instructions in the General Measurement Techniques‚
on page 168, and the specific instructions will be given in the following
paragraphs.
Current Programming and Readback Accuracy
This test verifies that the current programming and GPIB or RS-232 readback
functions are within specifications. Note that the readback values over the
remote interface should be identical to those displayed on the front panel. The
accuracy of the current monitoring resistor must be 0.01% or better.
You should program the power supply over the remote interface for this test
to avoid round off errors.
1Turn off the power supply and connect a 0.01 9 current monitoring resistor
(RM1) across the output to be tested and a digital voltmeter across the current
monitoring resistor (RM1) as shown in Figure A-1.
2Turn on the power supply. Select the low voltage range (8V/3A)† and enable
the output by sending the commands:
VOLT:RANG P8V (E3640A model)
OUTP ON
3Program the output voltage to full scale rated voltage (8.0 V)† and output
current to zero amps by sending the commands:
VOLT 8 (E3640A model)
CURR 0
4Divide the voltage drop (DVM reading) across the current monitoring resistor
(RM) by its resistance to convert to amps and record this value (IO). This value
should be within the limit of (0 A ± 10 mA). Also, note that the CC, Adrs, Limit,
and Rmt annunciators are on.
5Readback the output current over the remote interface by sending the
command:
MEAS:CURR?
†For E3640A model, and see Table A-3 for other models