I am looking for advice/recommendations on what IC's are good for analog to digital signal conversion. In a nutshell, I'm lost amidst the wide array of choices. I need to get signals from up to 20 thermocouples that measure steam pipe temperature. I also need to be able to do the same with some Rosemount pressure transmitters. I have to be able to record this data and display it (real-time) in graphical form. Anyway, probabaly a 16-bit situation. I'm going to build the A/D board, plainly and as simply as possible. Anybody ever monkey with anything like this???

Thanks!!

Curtis

 

Hi,

As you suggest, the number of A to D converters as as the number of pills Carter's used to crank out. Very few suggestions can be made, though, until you give some more data about the computer or microprocessor that will get the data.
Sure you need 16 bits? That's a lot of precision for temperature and pressure in steam pipes.

You say you're going to make the A to D board - does that also include all the signal conditioning circuitry, too? If it's a desktop computer, consider a card from computerspecialists.com - save yourself the trouble of reinventing the wheel. If it's going to feed data to a port, look up the external boxes from Dataq. Their software for live display is some of the best. Omega Engineering has lots of material and sensors for your applications as well.

 

I probably don't need 16-bit. I have looked at some of the available "off the shelf" products, and will probably go that way............however, being the anal retentive, excessive compulsive, gotta figure it out, kind of person I am, I'd still like to do some dabbling and prototyping. In the long run, I can forsee needing to be able to monitor, flow, pH, conductivity, and control some 2"-6" valves as well. I guess what I'm actually seeing as the end of the line is a sort of "mini-DCS". I'm always seeing things in the field that I could automate or make more user friendly for our guys that have to be out in the field (we go from jobsite to jobsite all the time....mostly new power plants).

I could go with an 8-bit single channel basis just to get the basic circuitry and logic concepts down. I will need signal conditioning I'm sure. I need to be able to utilize a Pentium/Windows based PC or a laptop, or both, with simplicity.

This will be an ongoing, long-term project. I figure the knowledge gained in exchange for the price of components is one the few good deals still available today. I've been hitting the Nat'l SemiConductor and Analog Devices websites with a fury!

Thanks,

Curtis