User`s guide

Chapter 3 Calibration Procedures
Constant Current (CC) Verifications
57
3
7 Program the output current to the full rated value (20.0 A)* or (7.0 A)** by sending
the command:
CURR 20.0 (E3633A)
CURR 7.0 (E3634A)
8 Divide the voltage drop (DVM reading) across the current monitoring resistor (R
M
)
by its resistance to convert to amps and record this value (I
O
). This value should be
within the limit of (20 A ± 50 mA)* or (7A ± 24 mA)**.
9 Readback 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
(I
O
± 35 mA)* or (I
O
± 15.5 mA)**.
CC Load Effect (Load Regulation)
This test measures the immediate change in output current resulting from a change in
the load from full rated output voltage to short circuit.
1 Turn off the power supply and connect the output to be tested as shown in
Figure 3-1 with the digital voltmeter connected across the 0.01 Ω current monitoring
resistor (R
M
).
2 Turn on the power supply. Select the 8V/20A* or 25V/7A** range, 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 maximum programmable value and the output current to the
full rated value (20.0 A)* or (7.0 A)**.
3 Set the voltage of the electronic load to (6.0 V)* or (23.0 V)** to operate it in constant
voltage mode since a voltage drop occurs on the load wires when
(20.0 A)* or (7.0 A)** flows 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.
4 Operate the electronic load in short (input short) mode. Record the current reading
immediately by dividing the voltage reading on the digital voltmeter by the resistance
of the current monitoring resistor. The difference between the current readings in step
(3) and (4) is the load regulation current. The difference of the readings during the
immediate change should be within the limit of (2.25 mA)* or (0.95 mA)**.
*For Agilent E3633A Model **For Agilent E3634A Model