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There is a way ... Posted by RS [Email] (#15) [Profile/Gallery] (more from RS) on Wed, 21 Jan 2015 06:11:07 In Reply to: Re: what ^he^ says, Justin VanAbrahams [Profile/Gallery] , Tue, 20 Jan 2015 12:52:48 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I found one unit that will convert a current signal (4-20 mA for those into controls lingo) to a resistance signal.
There are a few manufacturers of loop-powered pressure transducers that can use 12 VDC as the power source instead of the usual 24 VDC. Wika (a company that I occasionally spec) makes some pressure transducers like that.
So ... it's doable once you figure out the ohms to pressure curve.
Here's a link to a PDF for a current-to-resistance signal converter I dug up. It's probably not cheap, but oddball .... er .... um .... non-standard control loops require some special converters.
As you said before, the trick is figuring out the pressure-to-resistance correlation.
It would be a bandaid on what was state-of-the-art 30 years ago. 30 years!! Gees, time flies :-0
There's got to be some bright person out there who can write a program for a cheapia PLC to emulate the APC box using commercial, off the shelf pressure devices. The trick in that will be interpreting the knock sensor. Maybe it won't be such a cheap PLC after all.
http://apcs.com/atr167/atr167.pdf
->Posting last edited on Wed, 21 Jan 2015 09:00:29.
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