HP 3457A Service Manual page 128

Calibration 3457A
d. Repeat steps "cl " through "c5" for each of the remaining ranges.
e, Disconnect the resistance standard from the 3457A input terminals.
5-35. DC Current Offset Calibration - Front Terminals
5-36. Equipment Required. No equipment is needed for this procedure.
a. Be certain all leads are disconnected from the HP 3457A input terminals.
b. Select the DC Current Function. (Press the DCI function key).
c. Use the following procedure to calibrate the front terminal offset on the 1 A, 300 mA, 30 mA,
3 mA and 300 uA ranges beginning with the 1 A range.
1. Set the 3457A to the appropriate current range. (Use the it or i scroll key to select the proper range),
2. Access the Calibration Command. (Press the Blue SHIFT key, then the OFFSET COMP / C configura-
tion key). The display will show CAL.
3. Enter the value of the input - in this case 0. (NOTE: If the security feature has not been disabled (set to
0), it will be necessary to 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.
d. Repeat steps "cl " through "c4" for each of the remaining ranges.
5-37. DC Current Gain Calibration - Front Terminals
5-38. Equipment Required. A DC Current Source capable of providing 300 uA, 3 mA, 30 mA (+.007%),
300 mA (+,026%) and | A (+,04%) is required to calibrate the DC Current Function.
a. Connect the Current Source to the HP 3457A front panel I and LO input terminals. Set the output
of the Current Source to | A.
b. Use the following procedure to calibrate the front terminal gain on the | A, 300 mA, 30 mA, 3 mA
and 300 uA ranges beginning with the | A range.
1, Set the 3457A to the appropriate current range. (Use the { or | scroll key to select the proper
range).
2. Set the current source to provide a full-scale reading on the HP 3457A range selected.
3. Access the Calibration Command. (Press the Blue SHIFT key, then the OFFSET COMP / C con-
figuration key ). The display will show CAL.
4. Enter the value of the input current (in amps). (NOTE: If the security feature has not been disabled
(set to 0), it will be necessary to 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.
c. Repeat steps " bl " through " b4 " for each of the remaining ranges.
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