Agilent Technologies Agilent 34980A, Руководство по обслуживанию

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Calibration Procedures
3
34980A Service Guide 63
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 52 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.
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