Fermentation PID Temp Controller - Cooling AND Heating

[BloaterPaste]

Hello!

I have a PID Temp controlled chest freezer that I use for fermentation. I'm in Southern California, but even with our typically mild weather I'm having a hard time keeping the temp in the 60s where I want it.

So, I want to add a heating element. I have an old aquarium heater that I'm planning on putting in a mason jar of water for the heating element. But I'm not sure how to set up my PID to make that happen.

I have a TA7-SNR that runs my setup.

Here's my copy of the datasheet.

And, it's been working great since last summer. I have the OUT1 tripping the SSR to turn the freezer on/off within 2 degrees of my target temp. But, now I'd like to add in the heater and have it warm the space if the temp is lower that the target.

The controller claims to be dual temp, but I'm not sure if that's what I need. It has a setting to set it to heat/cool but not one to do both. I'm thinking that Alarm1 (relay on posted 3 and 4) feature could be used, but I'm not really sure if that will work.

Have any of you used a temp controller like this for heating and cooling? Can you give me any feedback or tips to get me going in the right direction? Did I forget any important info?

Thanks in advance!

 

[Kraiglight]

I'm after the same thing I have not bought a controller unit yet but I need one that can controll both when I need it

 

[brew_ny]

I'm after the same thing I have not bought a controller unit yet but I need one that can controll both when I need it

STC 1000 off ebay, Amazon, etc. are cheap easy to build and use

they work well but be sure to buy one that does both

all the best

S_M

 

[rcm_rx7]

My new fermentation chamber is going to use a PID for heating and cooling. I like the PID function much better than my old STC-1000, which worked, but had temp swings.

The alarm function will work fine, but you'll probably need another relay. And don't just buy the stc-1000, it doesn't have any PID function, and a relay is half the price. You'll get a better and more accurate fermentation control with a PID (that you already have).

Ok so looking at your PID, the out2/al2 is the output you'll use (looks like pin 5 & 6), you can hook up an ssr to the output, and have the ssr output controlling the heating pad or whatever. You could tune your system to stay within 1 degree I'm sure.


Sent from my iPhone using Home Brew

 

[ChuckO]

Be careful with PID controls on refrigeration. You should make certain to have a method to stop short cycle times to avoid startup compressor loads.

 

[augiedoggy]

Be careful with PID controls on refrigeration. You should make certain to have a method to stop short cycle times to avoid startup compressor loads.

yes this is needed, and caqn also cause temp swings.... pids out of the box without adjustments will constantly be turning the fridge or freezer on and off for very short increments of time...I believe this will cause things to fail quickly

the stc1000 has default setting to allow more of a swing but can be made to operate in a tighter tolerance with adjustment I believe however, again I dont think its wise to go too far with this.

 

[rcm_rx7]

You guys are right about the PID causing issues with the compressor. Although you can easily disable the PID function (and lose some fine tuning advantage). I think the best way to use this particular PID is to put the compressor on the alarm output, which can be set a few degrees away from your target temperature in the settings. Then you can still use the PID function to operate the heat. You can turn off P, I, and D individually of you want, so just set P to zero or turn off and set the hysteresis to a couple of degrees . There is still no need to use an STC-1000 here.

Looking at the data sheets for your PID, it looks like alarm 1 has a built in 5a/120v relay, so depending on your freezer it would probably run it without another relay. So set your alarm 1 temperature difference and hook that up to your freezer. Then have the ssr output go to your heating element. Double check the power draw of your freezer first. I think you can set this up without buying anything else.




Sent from my iPhone using Home Brew

 

[jimmayhugh]

If you're interested in a little more flexibility, expandability and control, as well as remote viewing and control, take a look at my TeensyPi and/or TeensyNet projects.

 

[RadicalEd]

I wouldn't use a submerged aquarium heater...it will raise the humidity, which will then all gather on the sides of the freezer, causing lots of condensation to mop up. I would use either a small electric space heater or a heat pad/fermwrap/heat tape.