# C100 - Fermentation Fridge



## ro_arnold (14/4/14)

Morning All,

After spending several days and a bit of money getting parts (so much that I now realise I could have bought an off the shelf temp controller) I'm not sure what I have will do what I want.

I got given two C100 type PIDs. I've hooked them up (with professional help) with an SSR.

Now I've read two threads across the internet where people mention that you can use them for a fermentation fridge by utilising the alarm feature so that it doesn't kick in your fridge constantly. 

Does anyone use one of these for fridge temp control? If so how have you wired it up?

Cheers and many thanks,

Rohan


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## scottfrompubs (14/4/14)

Hey Rohan,

could you please put up a link to thread you mentioned above? Just want to check that out.


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## ro_arnold (14/4/14)

http://forum.northernbrewer.com/viewtopic.php?f=3&t=20195


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## ro_arnold (14/4/14)

That was one of the links.

Cheers,

Rohan


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## mr_wibble (14/4/14)

So the problem I read is that (according to posts on the linked forum) these type of PID controllers cycle the output too fast for a fridge compressor (via SSR).

From a C100 spec sheet I found, it seems there's a set of under/over temperature alarms.

So I _imagine_ you wire the SSR to the alarm signals (somehow), so the compressor is only activated when the fridge is say ±1° off target, or suchlike. This might give you in practice an error-factor range for the set-point, where the compressor is only turned on/off with high and low alarms.

I'm not trying to be an arse, but I can't really see the point of using a PID controller if this is what you need to do. I could not find a comprehensive manual for the C100, so maybe it already has this functionality built in. But from a quick read, there seems not be a parameter to set for it.

It's not too late to buy an STC1000, save the pid controllers and SSRs for another mash heat exchanger project.
You can get one for $20-30.


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## ro_arnold (15/4/14)

Its a fair call Mr Wibble, I'll see if it works and might order an STC-1000 in the mean time. 

Cheers,

Rohan


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