Calibration (Cont'd) - HP 3457A Service Manual

3457A Calibration
e. Enter the value of the input voltage (in volts), including the polarity.
(NOTE: I f the security feature has
not been disabled, (set to 0 ) it will be necessary to enter tlre input value, tlre delimiter (
,
)
and the security code).
f. Press the ENT key. The display will show CALIBRATING while the calibration routine is running.
g.
Set the output of the Voltage Source t o 0 V and disconnect it from the HP 3457A input terminals.
5-27. Two-Wire Ohms Offset Calibration
-
Front Terminals
5-28. Equipment Required. A low thermal short (copper wire) is required for this procedure.
a. Select the 2-Wire Ohms Function.
(Press the O H M function key).
b. Connect a short between the Front Panel HI and LO input terminals.
c. Use the following procedure to calibrate the front terminal offset on the 30 ohm, 300 ohm,
3 Kohm, 30 Kohm, 300 Kohm, 3 Mohm and 30 Mohm ranges beginning with the 30 Mohm range.
I. Set the 3457A to the appropriate resistance range.
(Use the
t
or
1
scroll key t o select the proper
range).
2. Access the Calibration Command.
(Press the Blue 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 resistance
-
in this case 0.
(NOTE: If the security feature has not been
disabled, (set t o 0 ) it will be necessary t o cnter the input value, the delimiter
(
,
) and the security code).
4. Press the
ENT
key. The display will show
CALIBRATINQ
while the calibration routine is
running.
d. Repeat steps
"
c l " through " c4 " for each of the remaining ranges.
e. Remove the short from the Front Panel HI and LO Input Terminals.
5-29. Two-Wire Ohms Gain Calibration
-
Front Terminals
5-30. Equipment Required. Resistance Standards of 30 Ohms (+.2O/o), 300 Ohms (f.02%), 3 Kohms (f .OO3O/o),
30 Kohms (+.001%), 300 Kohms (*.001%), 3 Mohms (2.002%) and 30 Mohms (2.009%) are required t o
calibrate the 2-Wire Ohms Function.
a. Run the Ohms Auto-Calibration routine.
(Press the AUTO C A L configuration key, enter the number 3 and
press the ENT key).
b. Set the Resistance Standard to 30 MOhms and connect it to the HP 3457A front panel HI and LO
input terminals.
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.
I. Set the 3457A t o the appropriate Resistance range.
(Use the or scroll key t o select t k ~ proper.
range).
2. Set the resistance standard t o the full-scale resistance of HP 3457A range selected.