HP 3457A Service Manual page 89

Operational Verification Tests
Rear Input Operational Verification Tests (Standard Instrument) Cont'd
3457A
2. Use the Test Record to record the offset readings of the 3 Kohm, 30 Kohm and 300 Kohm ranges.
3. If any of the offset readings are beyond the limits specified in Table 4-32 and on the Test Record,
the instrument should be calibrated. Refer to Section V of this manual for calibration procedures.
B457A 3457A |3457A | 90 day limits | 1 year Limits
Input Range | Set Up
Short 3 Kohm | OHMF | 0.000007 Kohm | 0.000007 Kohm
Short 30 Kohm | oHMF | 00.00007 Kohm | 00.00007 kKohm
Short |300 Kohm | OHMF | 000.0008 Kohm | 000.0008 Kohm
Table 4-32. 4-Wire Ohms Offset Test Limits (Rear Terminals)
Rear Input Operational Verification Tests
(44491A General Purpose Relay Assy)
SHORTING WIRES
4 WIREQ
2 WIRE
A
Figure 4-21. HP 44491A Terminal Block Assembly Connections
4-99. Preliminary Steps
4-34
1. Connect shorting wires to the channel 10 inputs of the Terminal Block assembly as shown in
Figure 4-21.
2. Select the Scanner Input. (Press the TERM configuration key, enter the number 2 and press the ENT
key).
The 44491A Relay Assembly and the 3457A Multimeter must have been calibrated
as a unit for these tests to apply. Calibration procedures are provided in Section V
of this manual.