Adjust R43
Adjust for 0V at Pin1 of U9
Figure 10-2: Register A Offset Zero Calibration
Register B Voltage Offset Zero Trim
•
Touch the tip of the positive DVM lead to pin 1 of U9.
•
While observing the DVM, adjust R43 for 0V on the DVM. Get as close to
absolutely zero volts as possible.
Range Switch Voltage Calibration
The procedure is very similar to the offset zero calibrations, and is performed only after
the offset zero calibrations have been completed. All measurements are taken from pin 1
of U8. It uses the same setup as the offset zero, with a couple of extra settings.
The goal of the calibration is to adjust the output voltage of one stage for each position of
the rotary Range Switch. The calibration begins with Range Switch position 1 (full anti-
clockwise position) and ends with Range Switch position 8 (full clockwise position). Of
course, if the variable range option is installed, Range Switch Position 8 is not calibrated.
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