I have Visual Studio Pro, but do not know much about it. So, assuming I can use this to do all of my programming, that is what I would use.
dp is delta pressure or pressure drop across each of the filters. This will tell me when the filters are starting to get clogged, as the drop goes too high. ex: 2psi may be normal when the filter is new at a certain flow rate, but 10psi would indicate it is clogging up at the same flow rate.
I would have 3 pressure readings. p1 (incoming pressure to first filter), p2 (between filter 1 and filter 2) and p3 (downstream of filter 2). The difference between p1 and p2 would be dp1 (pressure drop for filter 1) and the difference between p2 and p3 would be dp2 (pressure drop for filter 2).
In instrumentation, a common practice is to convert loop power 4-20ma signals to voltage by placing a high-tolerance 250 ohm resistor in line withe the return (-) wire of the loop from the sensor. Sense the signal is in current, you can use V=IR to convert to a voltage signal. This is what I am doing here.
So 100psi/1024 = 0.098psi/count which is OK for my purposes given that I am only concerned drops in the whole number magnitude.
So my app would need to read the counts, do a little subtracting, and then convert to psi as I (the non-programmer) see it.
I apologize for not being more clear about what I need. I think my main deficiency is the absolute lack of knowledge on how the arduino and the shields work, especially over ethernet. I am assuming I will assign a fixed IP for the ethernet shield and my read commands will address the ip each time I call it. That's about where I stop with regard to how to make this thing happen.
I was hoping there may be some bits of code that I could piece together and with a little learning curve, I could get it to work and learn something at the same time.
Thanks for any help you can offer.
Arlian