HP 3457A Service Manual page 87

Operational Verification Tests
Rear Input Operational Verification Tests (Standard Instrument)
REAR TERMINALS 450V pk MAX
TO FRONT TERMINALS ORS
CUSENSE (4 wiRE) 'INPUT (2 WIRE)
HI LO HI LO
AX
Figure 4-20. Standard Instrument Rear Input Test Connections
4-90. 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
4-91. DC Voltage Function - Rear Terminal Offset Test
4-92. Equipment Required. A low thermal short (copper wire) is required for this procedure,
lL. Set the HP 3457A to the DC Voltage function (DCV) and the number of digits displayed (DIGITS
DISP) to six.
2. 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.
3. If any of the offset readings are beyond the limits specified in Table 4-29 and on the Test Record,
the instrument should be calibrated. Refer to Section V of this manual for calibration procedures.
3457A
3457A 134570 | 34570 90 day limits 1 year Limits
Input |Range | Set Up High Low High Low
Short | 30 v | pcv + 00.00020 v - 00.00020 v + 00.00020 v - 00.00020 v
Short 3v | pev + 0.000007 v 0.000007 v + 0.000007 v 0.000007 v
Short |300 mv| pcv +000.0040 mv -000.0040 mv +000.0040 mv =000.0040 mv
4-32
Table 4-29. DC Voltage Offset Test Limits (Rear Terminals)