Omega CN8592-R1-DC2 PID

[burdbrew]

Happy holidays.

I was lucky enough to have two of the above mentioned controllers given to me. I use an Auber PID to control my RIMS, and I'm extremely happy with that. These guys are bonus. I was thinking I would try to wire this controller up to measure the temperature in my mash (thermowell perhaps).

I've done some reading and searching on how to use this as a glorified thermometer, and my real question comes down to using an RTD sensor. RTD sensors typically have three wires; this PID only has placement for two wires. I can't find a two wire RTD to save my life (all though my search skills probably lack).

Is there a way to make a three wire RTD talk to this PID?

I am work-shopping uses for the second controller. Good problems I think.

 

[processhead]

I think its possible to use a three wire RTD on a 2 wire controller.
Try connecting just two leads to the controller. Some combination should display the room temperature on the controller. That should tell you that you have the right wires connected.
Three wire RTDs are used to compensate for long lead lengths between the RTD and the controller. Really are not important for the average homebrewing setup.

 

[big_len]

^ Exactly what he said, 2 of the wires of a 3 wire probe do exactly the same thing. The 'hobbyist' level 3-wire pt100s generally come with 1 red and 2 blue wires so all you would have to do is wire up the red and one blue to your PID

 

[cank]

I have an OMEGA CN77323 PID and had to email the company for wiring help. They responded within a day and worked with me until I had it resolved. Works great and I can say it is not just a temp probe, just different from Auberins.

Yours looks like it is the model that controls a relay instead of an SSR tho.

 

[ducati]

+2

Only two of the wires are required to measure temperature although at the expense of some accuracy. Somewhat off topic: repeatability will be the same as if you used a controller with 3-wire capability.

The third wire allows the electronics (if so equipped) to measure resistance in the wiring between the RTD and controller input and use that resistance to improve the measurement accuracy.

So keep the wiring as short as possible and use larger wire gauge to keep the wiring resistance lower and therefore any error smaller.

 

[burdbrew]

Thanks for the replies and the knowledge.

I have an OMEGA CN77323 PID and had to email the company for wiring help. They responded within a day and worked with me until I had it resolved. Works great and I can say it is not just a temp probe, just different from Auberins.

Yours looks like it is the model that controls a relay instead of an SSR tho.

I would use one of these units to control the RIMS if I didn't already have the Auber PID set up. I don't see the thermometer solution as being permanent, but I thought it would be interesting to create a project for myself for the time being.

The website says it will work an SSR, so that should be useful should I want to expand. From the site:

Output Options
SPST Relay: 5 Amps @ 120 Vac , 5 Amps @ 240 Vac
dc Pulse: 5 Vdc pulsed
SSR: Solid-State Relay, 120/240 Vac, zero Voltage switched 1 Amp continuous 10 Amp surge @ 25°C.

I would like to be able to put a probe in the mash and remove when I'm done, as opposed to cutting a whole and installing a thermowell. I'm trying to think of a way to create an RTD probe that I can immerse in the mash. I'm probably overthinking this.