HP 3457A Service Manual page 127

Calibration
d. Repeat steps
"
c l
"
through
"
c4
"
for each of the remaining ranges.
e. Remove the shorting wires from the Front Panel
Source and Input terminals.
5-33. Four-Wire Ohms Gain Calibration
-
Front Terminals
5-34. Equipment Required. Resistance Standards capable of providing 30 Ohms (f.2%), 300 Ohms (+.02%),
3 Kohm
(f
.003°/0' / o), 30 Kohms (f.OOlO/o), 300 Kohms (f .OOln/o), 3 Mohms (f.002°/0) and 30 Mohms (f.009%) are
required t o calibiate the 4 - ~ i ; e Ohms Function.
RESISTANCE
STANDARD
I
Figure 5-2. Input Connections for 4-Wire Ohms Gain Calibration
a. Run the Ohms Auto-Calibration routine.
(Press the AUTO C A L configuration key, enter the number 3 unil
press the ENT key).
b. Set the Resistance Standard t o 30 MOhms and connect it to the HP 3457A front panel HI and LO
Input terminals and ! 2 Sense HI and LO terminals as shown in Figure 5-2.
c. Use the following procedure t o calibrate the Gain on the 30 Mohm, 3 Mohm, 300 Kohm, 30 Kohm,
3 Kohm, 300 Ohm and 30 Ohm ranges beginning with the 30 Mohm range.
1. Set the 3457A to the appropriate Resistance range.
(Use the
7
or scroll key t o select the propcJr
range).
2. Set the resistance standard t o the full-scale resistance of HP 3457A range selected.
3.
Access the Calibration Command.
(Press the Blue S H I F T key, then the OFFSET C O M P
/
C configuru-
tion key).
The display will show CAL.
4. Enter the value of the input resistance (in ohms).
(NOTE: If the security feuture hus not Been disuBIecl
(set t o 0), it will be necessary t o enter the input value, the delimiter
(
,
) and the security code).
5. Press the ENT key. The display will show CALIBRATING while the calibration routine is
running.