I did already ask this question on the "data converter" forum but from advice there I'm asking again here, see:
For a PLC like application I have to design a module that measures temperature (PT1000, 2-wire), pH and EC (2 electrode kind).
I'm using CN0398, CN0411 and CN0359 as reference material.
The pH and temperature conditioning circuits are known to me but an EC measurement is new.
Due to the tight space requirements I would like to use the AD7779.
As I see it this would negate the need for the additional S&H amplifiers as used in CN0359 and CN0411 due to the AD7779' simultaneous sampling.
I'm planning on measuring voltage and current simultaneous so no precision gain resistor are required as used in CN0411 .
I'm I correct in this assumption? Do you see some issues with this approach?
The additional 50/ 60Hz filtering can be done in software.
We have a two EC designs that use discrete ADC's and might be able to get you jump started on your work. CN0357 uses the AD7790 and the CN0396 uses the AD7798. Both designs have hardware and software available that you can use to quickly prototype with to realize the concepts you are trying to accomplish. All the software for these designs are available up on the Analog Devices GitHub repository.