Agilent Technologies 6622A Service Manual page 39

d. Multiply the voltage
monitoring resistor by 10 to convert to amps and record
this value (Io). Note also the current reading on the
front panel display. The readings should be within the
limits specified below for the particular output type
being tested.
Prog. Accuracy
Output (DVM Reading X10)
40WLV 80 mA ± 50 mA
80WLV 130 mA ± 100 mA
40WHV 50 mA ± 20 mA
80WHV 70 mA ± 40 mA
e. Read back the output current from the selected channel
over the GPIB to the controller by running the
following program:
10 OUTPUT 705; "IOUT? < ch > "
20 ENTER 705; A
30 DISP A
40 END
f. Record the value displayed on the controller. This value
should be within the limits specified below using the Io
reading noted in step d.
Readback Accuracy
Output (Controller Display)
40WLV Io ± 10 mA
80WLV Io ± 20 mA
40WHV Io ± 4 mA
80WHV Io ± 8 mA
g. Program the selected outputs voltage to 5 V and the
current to the Low Range Full Scale Current value (see
Table 3-2) by sending the strings:
VSET < ch >, 5
ISET < ch >, <5, 2, 10, or 4 >
h. Multiply the voltage
monitoring resistor by 10 to convert to amps. Record
this value (Io). Note also the current reading on the
front panel display. The readings should be within the
limits specified below for the particular output type
being tested.
Prog. Accuracy
Output (lo = DVM Reading X 10) (Front Panel LCD)
40WLV 5 A ± 58 mA
80WLV 10 A± 116 mA
40WHV 2 A ± 23 mA
80WHV 4 A± 46 mA
i. Run the program listed in step e. Record the value
displayed by the controller. This value should be within
the limits specified below using the Io reading noted in
step h.
Readback Accuracy
Output (Controller Display)
40WLV lo ± 15 mA
80WLV Io ± 30 mA
40WHV lo ± 6mA
80WHV Io ± 12 mA
j. Repeat steps a through i for each output in your supply.
3-24 Negative Constant Current (- CC) Operation. This test
verifies the readback and display accuracies when the
drop across the current
Display Accuracy
(Front Panel LCD)
Io ± 15 mA
lo ± 25 mA
Io ± 4.5 mA
Io ± 8.5 mA
drop across the current
Display Accuracy
lo ± 20 mA
lo ± 35 mA
Io ± 6.5 mA
lo ± 12.5 mA
output is in negative current limit operation. It also checks
that the negative current limit has two different values
depending upon the output voltage.
a. Turn off the supply and connect the output to be tested
as shown in Figure 3-12.
b. Set the external power supply to 5V and its current
limit to 1.5 times (approximately) the Low Range Full
Scale current value (see Table 3-2) of the output under
test. For example, if the Low Range Full Scale current
value is 2 A, set the external supply's current limit to
about 3 A.
c. Turn on the supply and select the output to be tested
(OUTPUT SELECT key on the front panel).
d. Program the selected output channel to 0V by sending
the string:
VSET < ch >, 0
e. Multiply the voltage drop across the current monitoring
resistor by 10 to obtain the current sink value (Is) in
amps and record the value. Record also the current
reading on the display. The readings should be within
the limits specified below for the particular output type
being tested. Note that the CC annunciator must be on.
Neg. Current Limit
Low Range Output V
Output (Is= DVM Reading X 10)
40WLV
80WLV
40WHV
80WHV
f. Read back the sink current from the selected channel
over the GPIB by entering and running the program
listed in step e of paragraph 3-23.
g. Record the value displayed on the controller. This value
should be within the reading (Is) noted in step e and the
limits specified below.
Output
40WLV
80WLV
40WHV
80WHV
h. Raise the voltage of the external supply up to
approximately 12 V (40WLV or 80WLV outputs) or to
26 V (40WHV or 80WHV outputs) as indicated on your
supply's front panel and note that the sink current (Is)
changes from the previous value to a value within the
range indicated below.
Output
40WLV
80WLV
40WHV
80WHV
i. Repeat this test (steps a through h) for each output in
your supply.
3-11
Display Accuracy
(Front Panel LCD)
5.35 to 5.85 A Is ± 42 mA
10.7 to 11.7 A Is ± 78 mA
2.15 to 2.35 A Is ± 13.5 mA
4.3 to 4.7 A Is ± 30 mA
Readback Accuracy
(Controller Display)
Is ± 37 mA
Is ± 73 mA
Is ± 13 rnA
Is ± 29.5 mA
Neg. Current Limit
High Range Output V
(DVM Reading X 10)
2.25 to 2.55 A
4.5 to 5.1 A
0.9 to 1.02 A
2.1 to 2.5 A