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Table 7. A/D Converter Input Voltage Ranges
Amplifier
Gain
1
2
4
5
*
8
10
16
20
* 4–20 mA operation is available with an amplifier gain of 8
When using channels AIN0–AIN3 for current measurements, remember to set the corre-
sponding jumper(s) on header JP6.
The A/D converter inputs are factory-calibrated and the calibration constants are stored in a
separate EEPROM.
3.4.1 A/D Converter Calibration
To get the best results form 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 table in software only holds calibration con-
stants based on mode, channel, and gain.
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.
Mode
Single-Ended, unipolar
Single-Ended, bipolar
Differential, bipolar
Milli-Amp
These sample programs are found in the
Section 4.2.4 for more information on these sample programs and how to use them.
User's Manual
Voltage Range
Single-Ended
Single-Ended
Unipolar
Bipolar
0–20 V
±10 V
0–10 V
±5 V
0–5 V
±2.5 V
0–4 V
±2 V
0–2.5 V
±1.25 V
0–2 V
±1 V
0–1.25 V
±0.625 V
0–1 V
±0.5 V
Other factors affecting the calibration must be taken
Read
AD_RD_SE_UNIPOLAR.C
AD_RD_SE_BIPOLAR.C
AD_RD_DIFF.C
AD_RD_MA.C
ADC
Differential
Bipolar
± 20 V
± 10 V
± 5 V
± 4 V
± 2.5 V
± 2 V
± 1.25 V
± 1 V
ADC_CAL_SE_UNIPOLAR.C
ADC_CAL_SE_BIPOLAR.C
ADC_CAL_DIFF.C
ADC_CAL_MA.C
subdirectory in
SAMPLES\BL2600
mV per Tick
10
5
2.5
2.0
1.25
1.0
0.625
0.500
Calibrate
. See
25
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