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User’s Manual 79
B.4.2.4 A/D Converter Calibration
To get the best results from the A/D converter, it is necessary to calibrate each mode (sin-
gle-ended, differential, and current) for each of its gains. It is imperative that you calibrate
each of the A/D converter inputs in the same manner as they are to be used in the applica-
tion. For example, if you will be performing floating differential measurements or differ-
ential measurements using a common analog ground, then calibrate the A/D converter in
the corresponding manner. The calibration must be done with the attenuator reference
selection jumper in the desired position (see Figure B-5). If a calibration is performed and
the jumper is subsequently moved, the corresponding input(s) must be recalibrated. The
calibration table in software only holds calibration constants based on mode, channel, and
gain.
Other factors affecting the calibration must be taken into account by calibrating
using the same mode and gain setup as in the intended use.
Sample programs are provided to illustrate how to read and calibrate the various A/D
inputs for the three operating modes.
These sample programs are found in the Dyiamic C
SAMPLES\RCM3600\ADC
subdirectory.
See Section 3.2.2 for more information on these sample programs and how to use them.
Mode Read Calibrate
Single-Ended, one channel
— AD_CALSE_CH.C
Single-Ended, all channels
AD_RDSE_ALL.C AD_CALSE_ALL.C
Milliamp, one channel AD_RDMA_CH.C AD_CALMA_CH.C
Differential, analog ground
AD_RDDIFF_CH.C AD_CALDIFF_CH.C