HP 3457A Service Manual page 88

3457A
Operational Verification Tests
Rear Input Operational Verification Tests (Standard Instrument) Cont'd
4-93. DC Current Function - Rear Terminal Offset Test
4-94. Equipment Required. This procedure does not require any test equipment.
1. Set the HP 3457A to the DC Current function (DCI), 3 mA range, and the number of digits dis-
played (DIGITS DISP) to six.
2. Use the Test Record to record the current offset readings on the 3 mA and | A ranges.
3. If any of the offset readings are beyond the limits specified in Table 4-30 and on the Test Record,
the instrument should be calibrated. Refer to Section V of this manual for calibration procedures.
3457A | 3457A | 34570 90 day limits 1 year limits
Input |Range | Set up High | Low High | Low
Open | 3 ma| cl +0.000104 ma -0.000104 mA +0.000104 ma =0.000104 mA
open | 30 ma} oc1 +00.00104 ma -00.00104 ma +00.00104 ma -00.00104 mA
Table 4-30. DC Current Offset Test Limits (Rear Terminals)
4-95. 2-Wire Ohms Function - Rear Terminal Offset Test
4-96. Equipment Required. A low thermal short (copper wire) is required for this procedure.
1, Set the HP 3457A to the 2-Wire Ohms Function, 3 Kohm range and the number of digits displayed
(DIGITS DISP) to six.
2. Use the Test Record to record the offset readings for the 3 Kohm, 30 Kohm and 300 Kohm ranges.
3. If any of the offset readings are beyond the limits specified in Table 4-31 and on the Test Record,
the instrument should be calibrated. Refer to Section V of this manual for calibration procedures.
34578 3457A |3457A | 90 day limits | 1 year limits
Input Range | Set Up
Short 3 Kohm | OHM 0.000207 Kohm | 0.000207 Kohm
Short 30 Kohm | OHM 00.00027 Kohm | 00.00027 Kohm
Short |300 Kohm | OHM 000.0010 Kohm | 000.0010 kKohm
Table 4-31. 2-Wire Ohms Offset Test Limits (Rear Terminals)
4-97. 4-Wire Ohms Function - Offset Test
4-98. Equipment Required. A low thermal short (copper wire) is required for this procedure.
4-33