Preliminary Steps - HP 3457A Service Manual

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Performance Tests
3457A
Rear Input Performance Tests (44492A 10 Channel Multiplex Assy)
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44492A RELAY
SHORTING WIRES
4-58.
4-59.
4-60.
4-20
Figure 4-11. HP 44492A Terminal Block Assembly Connections
Preliminary Steps
1. Connect shorting wires to the inputs of the Terminal Block assembly as shown in Figure 4-11.
2. Select the Scanner Input. (Press the TERM configuration key, enter the number 2 and press the ENT
key).
The 44492A Multiplexer 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.
DC Voltage Function - 44492A Offset Test
Equipment Required. A low thermal (copper) shorting wire is required for this procedure.
1. Set the HP 3457A to the DC Voltage function (DCV) and the number of digits displayed (DIGITS
DISP) to six.
2. Close channel 0. (Press the CHAN configuration key, enter the number 0 and press the ENT key).
3. Test the HP 3457A input offset on the 300 V, 30 V, 3 V, and 300 mV ranges and record the reading
of each range on the Test Record provided at the end of this section. Begin with the 300 V range to
allow any thermal voltages which might affect the readings on the lower ranges to dissipate.
4. Test the HP 3457A input offset on channels 0 through 9 with the instrument set to the 30 mV
range. Record the reading of each channel on the Test Record provided at the end of this section.
5. If any of the offset readings are beyond the limits specified in Table 4-19 and on the Test Record,
the instrument should be calibrated or repaired. Refer to Section V of this manual for calibration
procedures.