For our application, we are using AD7264 as input stage.
The AD7264 will be fed with four analogue differential channels:
- 0 Vdc to 100 Vdc - two channels
- 0 Vdc to 10 Vdc - two channels
Datasheet defines two specific values for Vcm range
2 V for PGA = 1
(AVcc / 2) for 2 <= PGA <= 128
1. How to identify the "Vcm" run-time?
2. How to design the incoming differential signal attenuator if no Vcm is specified?
3. If Vcm is specified to be zero, how the ADC would handle -ve signal range as per the equation:
Analogue input range = (Vcm) +- (Vref / (2 x Gain)) and single +5 V supply operation?