HP 3457A Service Manual page 70

3457A Performance Tests
Rear Input Performance Tests (Standard Instrument) Cont'd
2. Test the HP 3457A input offset on the 300 V, 30 V, 3 V, 300 mV and 30 mY 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.
3. If any of the offset readings are beyond the limits specified in Table 4-11 and on the Test Record,
the instrument should be calibrated or repaired. Refer to Section V for calibration procedures.
3457A |3457A | 34578 90 day Limits 1 year Limits
Input |Range | Set Up High Low High | Low
short |300 v | ocv +000.0007 v -000.0007 v +000.0007 v -000.0007 v
short | 30 v | vev + 00.00020 v - 00.00020 v + 00.00020 v - 00.00020 v
short | 3 v | ocv + 0.000007 v - 0.000007 v + 0.000007 v - 0.000007 v
Short |300 mv} bev +000.0040 mv -000.0040 mv +000.0040 mv -000.0040 mv
short | 30 mv} pvcv + 00.00385 mv + 00.00385 mv + 00.00385 mv - 00.00385 mv
Table 4-11. DC Voltage Offset Test Limits (Rear Terminals)
4-43. DC Current Function - Rear Terminal Offset Test
4-44, Equipment Required. This procedure does not require any test equipment.
aes 1, Set the HP 3457A to the DC Current function (DCI), 300 uA 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 300 uA, 3 mA, 30 mA, 300 mA
and | A ranges.
3. If any of the offset readings are beyond the limits specified in Table 4-12 and on the Test Record,
the instrument should be calibrated or repaired. Refer to Section V for calibration procedures,
34570 |3457A | 3457A 90 day limits 1 year Limits
Input |Range | Set Up High | Low High Low
Open | 300 ua] ocI +000.0104 uA =000.0104 uA +000.0104 uA -000.0104 uA
Open | 3 mA] 0CcI +0.000104 ma -0.000104 mA +0.000104 mA -0.000104 ma
Open | 30 ma| cI +00.00104 ma =00.00104 mA +00.00104 ma +00.00104 ma
Open | 300 ma} odcI +000.0204 ma 000.0204 mA +000.0204 mA -000.0204 ma
open | 1 | ocI +0.000604 A -0.000606 A +0.000604 A -0.000604 A
Table 4-12. DC Current Offset Test Limits (Rear Terminals)
4-45. 2-Wire Ohms Function - Rear Terminal Offset Test
4-46. Equipment Required. A low thermal short (copper wire) is required for this procedure.
= 1. Set the HP 3457A to the 2-Wire Ohms Function, 30 Ohm range and the number of digits displayed
(DIGITS DISP) to six.