Get a PID temperature controller for your Cave

[ArnaudForestier]

Off topic, but does anyone happen to know of a pid that can be used to control a stand-alone humidifier?  At least until my cave is "normalized" and stuffed with cheese, I've an issue with staying in the high '80's RH; a second humidifier squeezes it to 92%, but I'd love to control the one I have to 95-98%.  The integral humidistat controls to only 90%RH.  I'd rather buy a pid and learn to program it, than even consider, at this juncture, one of the dedicated environmental controllers that cost a couple hundred $ U.S. or more.

[bmckee561]

Sorry for the untimely delay in responding to your question.  I have been busy with so many new things.

I found this controller on-line at the following link:  http://www.omega.com/ppt/pptsc.asp?ref=RHCN-7000_Series&Nav=temhu06

It is fairly inexpensive and can be used for ON/OFF type control.  You will need to purchase the Humidity Sensor also, but it should work well in controlling to a user specified setpoint.

Good Luck.

Salute!   

[ArnaudForestier]

Wow!  Fantastic, thanks so much.  Sorry for a newb question - but not familiar with "VDC," and not sure if this sensor would work with one of these controllers (PDF).  (Thanks again Francois).

Also, the sensor from the link I provided indicates "do not expose to condensing environments."  Does this mean it wouldn't work inside my cave, which has a ton of condensate everywhere?  (don't laugh if this is an electrical term....my fragile ego just can't take the scorn. ).  If this sensor wouldn't work, if I was driving a simple cool mist humidifier, would RHCN-7006 controller (this is correct, yes - household current?) and RHCN 7000-RP work well, for controlling a humidifier (or ag misting system, if I get to that point)?  Unless I'm driving a pump/ag misting system, I wouldn't need anything other than a PID and sensor, yes (e.g., no solenoid).

Secondly - another newb question - but how do you wire the probe to the PID?

Finally, assuming I can get a working marriage of controller and sensor, is it easy to program - how different from temp programming, if any?

Really grateful, bmckee.  Cheese to you, wish I could give a bundle at a time, as I'm sure this is helpful to a lot of people.   

[mrsick44]

Yes you have to be carefull with which type of PID you use for a fridge.  You can not turn a compressor on and off like a heater, it will damage the compressor.  You have to make sure the PID has a latched output, which will stay on until the temp is reached, then turn off and stay off until the upper temp is reached.  It has to have some differential in the temp settings.

Mike

I know this post is a bit old, but does this mean that a PID is not ideal for a chest freezer? I cant find any information on wether or not the compressor can tolerate the strain. This sounds like a better solution than the analog Freezer Temperature Controller types sold by home brew houses. Any input would be a blessing!
Thanks

[bmckee561]

Yes you have to be carefull with which type of PID you use for a fridge.  You can not turn a compressor on and off like a heater, it will damage the compressor.  You have to make sure the PID has a latched output, which will stay on until the temp is reached, then turn off and stay off until the upper temp is reached.  It has to have some differential in the temp settings.  MOST IF NOT ALL PID CONTROLLERS HAVE A BUILT IN AND ADJUSTABLE DELTA TEMPERATURE CONTROL SETUP.  THIS ENSURES THAT THE UNIT DOES NOT CYCLE ON/OFF TOO QUICKLY.

Mike

I know this post is a bit old, but does this mean that a PID is not ideal for a chest freezer? I cant find any information on wether or not the compressor can tolerate the strain. This sounds like a better solution than the analog Freezer Temperature Controller types sold by home brew houses. Any input would be a blessing!
Thanks

Mike:  The PID controller will work for most small refrigerators (like mine) but the addition of a interposing relay may be necessary to properly turn a larger unit on and off.  You essentially use the PID controller to control the interposing relay on and off and that in turn controls the unit .

I am installing one on my stand up freezer soon for better temperature control. 

Once I find a second stand up freezer, I intend on using my current unit as a cheese cave to replace the fabricated one I currently use.

Check out the website listed for the PID controller, they have operating manuals and detailed instructions for all of their products.

Good luck.

Salute!