Dc Current Function - HP 3457A Service Manual

Operational Verification Tests
Rear lnput Operational Verification Tests
(44491 A General Purpose Relay Assy)
2. Close channel 10. (Press the CHAN configuration key, enter the number 10 and press the ENT key).
3. Use the Test Record t o record the offset reading of the 3 ICohm range.
4. If any of the offset reading is beyond
*
0.000010 ICOhm, the instrument should be calibrated or
repaired. Refer t o Section V for calibration procedures.
4-106. DC Current Function
-
44491A Offset Test Limits
4-1 07. Equipment Required. This procedure does not require any test equipment.
1. Set the HP 3457A t o the DC Current function (DCI), 3 mA range, and the number of digits dis-
played (DIGITS DISP) to six.
2.
Use the Test Record t o record the current offset readings on the 3
mA
and 1
A
ranges.
3. If either of the offset readings are beyond the limits specified in Table 4-34 and on the Test
Record, the instrument should be calibrated or repaired. Refer t o Section V for calibration
procedures.
W A
Input
Rear lnput Operational Verification Tests
(44492A 10 Channel Multiplex Assy)
Open
Open
-
4 4 4 9 2 A RELAY
\
3457A
Range
\
SHORTING WIRE
Table 4-34. DC Current Offset Test Limits (44491A)
3 m A l D C I
3 0 m A
D C I
Figure 4-22. HP 44492A Terminal Block Assembly Connections
3457A
S e t Up
+0.000104 m A
+00.00104 m A
T e s t L i m i t s
- 0 . 0 0 0 1 0 4 m A
- 0 0 . 0 0 1 0 4 m A
H i g h Low
I