Selecting PID for chest freezer/kegerator

[terrazza]

I am needing help picking a PID to use for my chest freezer converted into a kegerator....

I want one that will flip an SSR that turns on the freezer's condensing unit. I would like to be able to control its cycle on and off time. On for a minimum of 10 minutes. Off for a minimum of 10 minutes. This to preserve the compressors life.

Glanced at auberins and saw only 199 second cycling....

Anyone know the best PID for this?

THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU

 

[day_trippr]

Why do you think a minimum compressor-on time is important wrt compressor life?

If you can get past that concern there are a number of controllers that will do just fine...

Cheers!

 

[HumulusHead]

Stc 1000 of course would be the answer. But it does only min off time.

I agree, I don't think it has to do with min run time


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[sandyeggoxj]

Minimum on doesn't seem like a big concern. Minimum off however... If your off time is long enough, 10+ minutes, then the temp will swing enough that the compressor will stay on for several minutes. I don't think that you want a PID algorithm controller your keezer. A few degree temp swing in the air temp is fine. As long as the beer stays fairly steady you'll be fine!

 

[day_trippr]

[...]A few degree temp swing in the air temp is fine. As long as the beer stays fairly steady you'll be fine!

Exactly.

For illustration of that point I'll offer up a plot of the temperatures in and around my keezer over the last twelve hours to show you can hold kegs of beer within +/- .75°F of target (while observing rather wild swings in the interior air temperature) and still have a lengthy cycle time (peak to peak it's running around 2:35 right now - and it's only that short because six of the seven kegs are around a quarter full).

This is managed by a $12 single-stage MH1210 controller available from numerous sources. I don't think there's reason to get any more exotic than that...

Cheers!

 

[sandyeggoxj]

Is the $12 controller also a sophisticated data logger with excel output?

 

[HumulusHead]

Ya I was wondering. How the heck do you get that output???? With 5 freaking loggers too????

Btw totally jell


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[day_trippr]

Is the $12 controller also a sophisticated data logger with excel output?

Not only is the $12 controller not capable of logging, my home-brewed temperature logger isn't sophisticated...

Cheers!