DAQ question
 

Ok this is actually a work-related question but here goes:

I need to measure and log different parameters (temperature, pH, Eh, {Ca2+}, etc in a bioreactor we are building. It looks to me like the easiest way to do this is to just buy a NI DAQ card and use their free software to continuously log the data. But I am not turning up much information on using DAQ cards to capture readings from electrodes. Is this going to work ok? They output a mV reading over a pretty big range (pH 4 to 10 is a 350 mV range) so I would think that this would work fine. But is there a lot of additional smoothing/conditioning circuitry on a pH meter that I don't know about? Anyone have any reasons why trying this is a bad idea? The electrodes are all BNC so I am assuming it's relatively easy to mate them to the DAQ card's analog inputs...

beware of noise on those low amplitudes.

Depends on the noise you get on the lines.
Depends on the scale of the DAQ -> trying to read mV on a 0 to 5V analog DAQ, no good -> instrumentation amplifiers from mV to V.

decent noise reduction, lots of products floating around (google :) ) ,
several IC's from Maxim , Analog.

http://www.analog.com/en/subCat/0,28...0%255F,00.html