Appendix Service Information
Constant Current (CC) Verifications
175
Service
Information
6Record the value displayed on the controller. This value should be within the
limit of (IO ± 5 mA).
7Program the output current to the full scale rated value (3 A)† by sending the
command:
CURR 3.0 (E3640A model)
8Divide 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:
9Readback the output current over the remote interface by sending the
command:
MEAS:CURR?
10 Record the value displayed on the controller. This value should be within the
limit of:
CC Load Effect (Load Regulation)
This test measures the change in output current resulting from a change in the
load from full rated output voltage to short circuit.
1Turn off the power supply and connect the output to tested as shown in
Figure A-1 with the digital voltmeter connected across the 0.01 9 current
monitoring resistor (RM1).
2Turn on the power supply. Select the low voltage range (8V/3A)†, enable the
output, and set the display to the limit mode. When the display is in the limit
mode, program the output voltage to the full scale rated value (8.0 V)† and the
output current to the full rated value (3 A)†.
3Set the voltage of the electronic load to (8.0 V)† to operate it in constant voltage
mode since a voltage drop occurs on the load wires. Check that the CC
annunciator is on. If it is not, adjust the load so that the output voltage drops
slightly. Record the current reading by dividing the voltage reading on the
digital voltmeter by the resistance of the current monitoring resistor.
E3640A E3641A E3642A E3643A E3644A E3644A
3 A ± 16 mA 0.8 A ± 11.6 mA 5 A ± 20 mA 5 A ± 20 mA 8 A ± 26 mA 8 A ± 26 mA
E3640A E3641A E3642A E3643A E3644A E3642A
(IO ± 9.5 mA) (IO ± 6.2 mA) (IO ± 12.5 mA) (IO ± 7.1 mA) (IO ± 17 mA) (IO ± 8.3 mA)
†For E3640A model, and see Table A-3 for other models