Programming instructions

24 Chapter 3 Adjustment Procedures
Note Take precautions to prevent thermal changes near the 4-wire short. You
should not touch the short after it is installed. If drafts exist, you should
cover the input terminals/short to minimize the thermal changes.
4. Execute the CAL 0 command. The multimeter automatically performs
the front terminal offset adjustment and the display shows each of the
various steps being performed. This adjustment takes about 5 minutes.
When the adjustment is complete, the multimeter returns to displaying
DC voltage measurements.
Rear Terminal Offset Adjustment
This adjustment compensates for internal offset errors for rear terminal
measurements.
1. Connect the 4-terminal short to the rear terminals.
2. Set the front panel Terminals switch to Rear.
3. After connecting the 4-terminal short, allow 5 minutes for thermal
equilibrium.
Note Take precautions to prevent thermal changes near the 4-wire short. You
should not touch the short after it is installed. If drafts exist, you should
cover the input terminals/short to minimize the thermal changes.
4. Execute the CAL 0 command. The multimeter automatically performs
the rear terminal offset adjustment and the display shows each of the
various steps being performed. This adjustment takes about 5 minutes.
When the adjustment is complete, the multimeter returns to displaying
DC voltage measurements.
5. Remove the 4-terminal short from the rear terminals.
DC Gain Adjustment
In this adjustment, the multimeter measures the standard voltage using its
10V range. The multimeter then adjusts its gain so that the measured value
agrees with the standard's exact value (specified using the CAL command).
The multimeter then measures its 7V internal reference voltage using the
10V range and stores both the 10V gain adjustment constant and the value
of the internal 7V reference. This adjustment also automatically performs the
DCV autocalibration with computes DC gain constants.
Equipment required: A DC voltage standard capable of providing 10 VDC
(the resultant accuracy of the 3458A depends on the accuracy of the voltage