HP 3457A Service Manual page 72

Performance Tests
3457A
Rear Input Performance Tests (44491A General Purpose Relay Assy)
4 WIREO 10 aL iz 13
tT
EAWIRE 44491A RELAY
SHORTING WIRES
Figure 4-10. HP 44491A Terminal Block Assembly Connections
4-49. Preliminary Steps
1. Short the Rear Input HI and LO terminals and the Q Sense HI and LO terminals as shown in
Figure 4-9,
2. Select the Rear Terminal Input. (Press the TERM configuration key, enter the number 2 and press
the ENT key.
NOTE
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.
4-50. DC Voltage Function - 44491A Offset Test
4-51. Equipment Required. Low thermal (copper) shorting wires are 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 input offset on the 300 V, 30 V, 3 V, 300 mV and 30 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 al-
low 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 7 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 4-15 and on the Test Record,
the instrument should be calibrated or repaired. Refer to Section V for calibration procedures.