Technical data

62 34980A Service Guide
3 Calibration Procedures
Gain Adjustment
The Internal DMM stores a single new gain correction constant each time
this procedure is followed. The gain constant is computed from the
calibration value entered for the calibration command and from
measurements made automatically during the adjustment procedure.
Most measuring functions and ranges have gain adjustment procedures.
Only the 100 M
 range does not have gain calibration procedures.
Adjustments for each function should be performed ONLY in the order
shown in the performance verification table. See “Performance Verification
Tests" on page 50 for the tables used for gain adjustments.
Gain Adjustment Considerations
• The zero adjustment procedure must have been recently performed
prior to beginning any gain adjustment procedures.
• The optional –10 Vdc adjustment should be performed only after
servicing the Internal DMM’s a- to- d converter.
• When performing a 4- wire ohms gain adjustment, a new gain correction
constant is also stored for the corresponding 2- wire ohms measurement
range. If desired, the 2- wire gain can be adjusted separately after the
4- wire ohms gain calibration is completed. If the 2- wire Ohms gain is
adjusted separately, the 2- wire Ohms function will not meet
specifications when offset compensated Ohms is used.
• During the ac voltage gain adjustments, some of the dc voltage gain
constants are used. Perform the dc voltage gain calibration before the
ac voltage gain calibration.
NOTE
Never turn off the instrument during a Gain Adjustment. This may cause
calibration memory for the present function to be lost.