Agilent Technologies 6622A Service Manual page 33

* An output channel cannot be programmed to 0 amps. If the output channel receives a command to go to 0 amps (or any positive
current below the minimum programmable value), it will set itself to the minimum programmable value.
3-13 CV Load Effect. This test measures the change in
output voltage resulting from a change in output current
from full to no load.
a. Turn off the supply and connect the output to be tested
as shown in Figure 3-3 with the DVM
between the +S and -S terminals, the Load switch
closed, and the Short switch opened.
b. Turn on the supply and select the output to be tested
(OUTPUT SELECT key on front panel).
c. Program the current of the selected channel to the Low
Range Maximum Programmable current value and the
output voltage to the Low Range Full Scale voltage
value (see Table 3-2) by sending the following strings:
ISET < ch >, < 5.15, 2.06, 10.3, or 4.12 >
VSET < ch >, < 7 or 20 >
d. Adjust the load for the Low Range Full Scale Current
value (see Table 3-2) as indicated on the front panel
display. The CV annunciator on the front panel must be
on. If it is not, adjust the load down slightly.
e. Record the output voltage reading on the DVM
connected to + S and - S.
f. Open the Load switch and again record the DVM
voltage reading. The difference between the DVM
readings in steps e and f is the load effect voltage and
should not exceed 2 mV.
g. Repeat steps a through f for each output in your
supply.
4 CV Source Effect. This test measures the change in
output voltage that results from a change in ac line voltage
from the minimum to maximum value within the line
voltage specifications.
a. Turn off the supply and connect the ac power line
through a variable voltage transformer.
b. Connect the output to be tested as shown in Figure 3-3
with the DVM connected between the + S and - S
terminals, the Load switch closed, and the Short switch
opened.
c. Adjust the transformer to 13% below the nominal line
voltage.
d. Turn on the supply and select the output to be tested
(OUTPUT SELECT key on the front panel).
e. Program the current of the selected output to the High
Range Maximum Programmable Current value and the
output voltage to the High Range Full Scale Voltage
connected value (see Table 3-3) by sending the following strings:
f. Adjust the load for the High Range Full Scale Current
value (see Table 3-3) as indicated on the front panel
display. The CV annunciator on the front panel must be
on. If it is not, adjust the load down slightly.
g. Record the output voltage reading on the DVM.
h. Adjust the transformer to 6% above the nominal line
voltage.
i. Record the output voltage reading on the DVM. The
difference between the DVM readings in steps g and i is
the source effect voltage and should not exceed 3 mV
(40WLV and 80WLV outputs) or 6 mV (40WHV and
80WHV outputs).
j. Repeat steps b through i for each output in your supply.
Be sure to turn off supply before performing step b.
3-5
ISET < ch >, < 2.06, 0.824, or 4.12 >
VSET < ch >, < 20 or 50 >