Help with Arduino DAQ

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Steven Sesselmann
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Help with Arduino DAQ

Post by Steven Sesselmann » Sun Apr 29, 2012 3:44 am

Hi Guys,

I am trying to put together a 4 channel DAQ, to measure PSU voltage, Cathode voltage, vacuum pressure and neutron counts.

I bought a USB Arduino board called http://www.freetronics.com/products/eleven it has six analog inputs.

My objective is to have one screen with four charts, each plotting one parameter in real time.

Before I throw myself up against a steep learning curve, I thought I would ask if any of you guys have already done this, and were willing to share some knowledge.

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

Tyler Christensen
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Re: Help with Arduino DAQ

Post by Tyler Christensen » Sun Apr 29, 2012 5:52 am

I have done what you describe, along with feedback controlling valves allowing the computer to run my fusor hands-free indefinitely at a target setting, be it voltage, current, pressure, etc.

Filtering will be your biggest enemy. You need to very, very thoroughly filter your voltage and current feedback from the fusor. I actually never got voltage reading to work through the arduino and ended up using a dedicated computer-connected DMM for that reading. Although I believe it is possible, and could probably design a filter to make it work at this point. With insufficient filtering, I just got ridiculously noisy and meaningless readings on the analog pins.

To filter the current feedback I just put a big film cap in parallel with the sense-resistor and that did fine for that. It was not, however, enough to filter the voltage and that would probably need an inductive network. It might be alright if you have an extremely clean and stable fusor where there is just pure clean voltage on it with no real fluctuations. This is not the case for mine though.


You will need to invert the signals for voltage and current since you will be getting negative signals and the arduino can only read positive voltages with respect to ground. This is trivial to do with an op-amp.


I don't have access to any of my code which is on my lab computer back at home, but I just send data packets over serial to my computer and plot them in real-time in a program I put together in VB.

Chris Trent
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Re: Help with Arduino DAQ

Post by Chris Trent » Sun Apr 29, 2012 5:52 am

I've got an arduino that I've been using for pump control. It works pretty well but I haven't done any graphing. Its a fairly simple matter to output analog pin readings to a serial port. In the arduino development environment they even have sample code for it.

Enjoy the learning curve. It's half the fun.

Jeroen Vriesman
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Re: Help with Arduino DAQ

Post by Jeroen Vriesman » Sun Apr 29, 2012 8:42 pm

I know someone using openscada with arduino.

I plan on doing the same.

Jerry Biehler
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Re: Help with Arduino DAQ

Post by Jerry Biehler » Mon Apr 30, 2012 1:07 am

Look at the data acquisiion kits from DataQ, they will do what you want for very cheap and you don't have to roll your own.

http://www.dataq.com/data-acquisition-s ... r-kits.htm

AllenWallace
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Re: Help with Arduino DAQ

Post by AllenWallace » Tue May 01, 2012 1:46 am

I rather like the TI launchpad. For under $5 you get a USB emulated COM port serial interface with a handful of i/o including 10 bit A/D. You have to be willing to program in C.

Dustin
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Re: Help with Arduino DAQ

Post by Dustin » Tue May 01, 2012 5:54 pm

Or you could use one of these
http://labjack.com/u3

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