Test; Preliminary Steps; Dc Voltage Function; Rear Terminal Offset Test - HP 3457A Service Manual

Operational Verif icrit ion Tests
Rear lnput Operational Verification Tests (Standard Instrument)
r
LtSENSE
I 4 W I R E )
I N P U T
r z
W I R E 1
R E A R T E R M I N A L S 450V pk M A X >
HI
LO
HI L O
I
TO F R O N T T E R M I N A L S O R *
0
A
C U R R E N T
FUSE
0
i
J
Figure 4-20. Standard Instrument Rear Input Test Corineclions
4-90. Preliminary Steps
1. Short the Rear lnput HI and LO terminals and the
IZ
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 f o r this procedure.
I . Set t h e I-TP 3457A t o the
DC
Voltage function (DCV) and the nun?ber of digits displayed (DIGITS
DISP) t o six.
2.
Test the H P 3457A input offset on the 30 V, 3 V and 300 niV ranges and record the reading of
each range o n the Test Record provided at the end of this section. Begin with the 30 V range t o allon
any thermal voltages which might affect the readings o n the lower ranges t o dissipate.
3. If any of the offset readings are beyond the limits specified in Table 4-29 and o n the Test Record,
t h e instrument should be calibrated. Refer t o Section V of this manual f o r calibration procedures.
3457A
I n p u t
S h o r t
S h o r t
S h o r t
3457A
Range
3 0
V
3
v
300
rnV
3457A
Table 4-29. DC Voltage Offset Test Limits (Rear Terminals)
S e t Up
D C V
D C V
D C V
90 day L i m i t s 1 y e a r L i m i t s
H i g h
+ 00.00020
V
+ 0.000007
V
+000.0040
rnV
H i g h
+
00.00020
V
+
0.000007 V
+000.0040 m V
Low
-
00.00020
V
-
0.000007
V
- 0 0 0 . 0 0 4 0
rnV
Low
-
0 0 . 0 0 0 2 0
V
-
0 . 0 0 0 0 0 7 V
- 0 0 0 . 0 0 4 0 rnV