HP 3457A Service Manual page 126

Cali bration 3457A
3.
Access the Calibration Command.
(Press the Blue S H I F T key, then the OFFSBI' C O M P
/
c
configuration key).
The display will show CAL.
4. Enter the value of the input resistance (in ohms).
( N O T E : I f the security feature has not been disabled
(set t o 0),
it
will be necessary t o enter the i n p n t value, the delinriter (
,
)
and the security code).
5. Press the ENT
key. The display will show CALIBRATING while the calibration routine is running.
d. Repeat steps
"
c l
"
through
"
c5
"
for each of the remaining ranges.
e. Disconnect the resistance standard from the 3457A input terminals.
5-31. Four-Wire Ohms Offset Calibration
-
Front Terminals
5-32. Equipment Required.
A low thermal short (copper wire) is required f o r this procedure. (Refer t o
Figure 5-1).
(
dB STAT
LAST
L
Figure 5-1. lnput Connections for Four-Wire Ohms Offset Calibration
a. Select the 4-Wire Ohms Function.
(Press the Blue S H I F T key, then the O H M
/
O H M F key).
b. Connect the short across the Front Panel HI and LO lnput Terminals and the f 2 Sense HI and LO
terminals as shown in Figure 5-1.
c.
Use the following procedure t o calibrate the front terminal offset on the 30 Mohrn, 3 Mohrn,
300 Kohm, 30 Kohm, 3 Kohm, 300 Ohm and 30 Ohm ranges beginning with the 30 Mohm range.
1. Set the 3457A t o the appropriate resistance range.
(Use the
or scroll keys t o select the proper
range).
2.
Access the Calibration Command.
(Press the
Blne
S H I F T key, then the OFFSET C O M P
/
C configura-
tion key).
The display will show CAL.
3. Enter the value of the input
-
in this case 0.
( N O T E : I f the secnrity feature has not been disabled (set t o
0), it will be necessary t o enter the input value, the delimiter
(
,
)
and the security code).
4. Press the ENT key. The display will show CALIBRATING while the calibration routine is
running.