HP 3457A Service Manual page 90

3457A Operational Verification Tests
Rear Input Operational Verification Tests
eS (44491A General Purpose Relay Assy)
4-100. DC Voltage Function - 44491A Offset Test
4-101. 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 HP 3457A input offset on the 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 30 V range to allow
any thermal voltages which might affect the readings on the lower ranges to dissipate.
4. If any of the offset readings are beyond the limits specified in Table 4-33 and on the Test Record,
the instrument should be calibrated or repaired. Refer to Section V for calibration procedures.
3457A |3457A | 3457A Test Limits
Input |Range | Set Up High Low
Short 30 Vv DcVv + 00.00020 v - 00.00020 v
Short 3.v | pev + 0.000010 v - 0.000010 v
TY short |300 mv] pcv +000.0070 mv -000.0070 mv
Table 4-33. DC Voltage Offset Test Limits (44491A)
4-102. 2-Wire Ohms Function - 44491A Offset Test Limits
4-103, Equipment Required. Low thermal (copper) shorting wires are required for this procedure.
1. Set the HP 3457A to the 2-Wire Ohms Function, 3 Kohm range. Set the offset compensation
(OFFSET COMP) on, 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. Use the Test Record to record the offset reading for the 3 Kohm range.
4. Test the ohms offset on channels 0 through 7 with the instrument set to the 3 Kohm 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 + 0.002207 KOhms, the instrument should be calibrated or
repaired. Refer to Section V for calibration procedures.
4-104. 4-Wire Ohms Function - 44491A Offset Test Limits
4-105. Equipment Required. Low thermal (copper) shorting wires are required for this procedure.
I. Set the HP 3457A to the 4-Wire Ohms Function (OHMF). Set the offset compensation (OFFSET
COMP) on, and the number of digits displayed (DIGITS DISP) to six.