HP 3457A Service Manual page 92

Operational Verification Tests
Rear Input Operational Verification Tests
(44492A 10 Channel Multiplex Assy)
4-1 08. Preliminary Steps
1.
Connect a shorting wire t o the channel 0 inputs of the Terminal Block assembly as shown in
Figure 4-22.
2. Select the Scanner Input. (Press the TERM config~~ration key, enter the number 2 and press the ENT
key).
The 44492A Mlrltiplcxer Arscmhly and the 3457A Mllltimctcr rnrlsf have hccn
calibrated as a ~ m i t for these t e ~ t s to apply. Calibration procedlrre.5 are provided irt
Scction V o f thi.5 manilal.
4-109. DC Voltage Function
-
44492A Offset Test
4-1 10. Equipment Required. A low thermal (copper) shorting wire is required for this procedure.
1. Set the HP 3457A t o the DC Voltage function (DCV) and the number of digits displayed (DIGITS
DISP) t o 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 300 mV range and record the reading on the Test Record
provided at the end of this section.
4. If the offset reading is beyond
+
000.0070 mV, the instrument should be calibrated or repaired.
Refer t o Section V for calibration procedures.
4-1 11. 2-Wire Ohms Function
-
44492A Offset Test Limits
4-1 12. Equipment Required. A low thermal (copper) shorting wire is required for this procedure.
1. Set the HP 3457A t o the 2-Wire Ohms Function, 3 Kohm range. Set the offset compensation
(OFFSET COMP) on, and the number of digits displayed (DIGITS DISP) t o six.
2. Close channel
0.
(Press the CHAN configuration key, enter the number 0 and press the ENT key).
3.
Use the Test Record t o record the offset reading for the 3 Kohm range.
4. Test the ohms offset on channels 0 through 9 with the instmment set t o the 3 K o h n ~ 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
f
0.004210 KOhm, the instrument should be calibrated or
repaired. Refer t o Section V for calibration procedures.