PID for smoker

[Sig]

Anyone here use their casting PID for controlling a smoker fan? Just got a smoker for Christmas & I already want to accessorize it.

[bangerjim]

Don't use the same controller for your smoker! They are dirt cheap. Get another one if you wish to mess with a fan. But the fan you have in there is probably a shaded pole motor and will NOT work with variable voltage. All you will do is burn out the fan motor. If an elecric smoker like I have, you can put the controller in charge of the heating element. But I would not wast time. My smoker already has an excellent digital controller on the temp.....(within 2F).

You cannot PID-control the speed of an induction type motor.....only brush type AC/DC motors.

You might be able to use on-off control from the PID controller on a fan like that. Just buy another controller and SSR and try it. Remember the moder PID controllers use fuzzy logic to "learn" the process control. SWappign it out/moving it just confuses it and takes unneeded time re-learning the new process parameters.

Hey anyone can afford $35!

Banger

[Morgan61]

I do use a different probe for my smoker than the one I use in my melting pot - no fan in mine, just the heat control.
Works good.

[Sig]

Thanks for the replies Banger & Morgan 61. I've been looking at what others on the web have been doing. They typically use the PID on/off circuit to control a 12v DC computer fan or such. This is for Kamado style smokers (not electric). I was figuring on using a wall wart plugged into my PID. I have spare probes but I did not think about the learning/relearning process of the PID.

[HATCH]

Banger is correct that most PIDs autotune to the device they are controlling.

PIDs do not vary the voltage to the device they are controlling.
Basically its just a ON/OFF switch.
You use a Solid State Relay (SSR) because the MTBF (mean time before failure) is normally between in excess of 50 million operations
Compared to a standard relay which under load could fail as soon as 100K cycles.

Now you are thinking 100K cycles is a lot but in reality if we say you use your casting pot 1 day a week for 8 hrs every week and we say for discussion that after initial heat, it cycles once per min of use (to maintain heat). Then after 4 years of use your relay will fail.
A SSR will fail in 2000 years.... LOL

Keep in mind that it cycles a lot more then just once per minute.
I worked in the HVAC industry for 15 years supplying SSR to customers and techs.
Unless they got hit by a surge, I have only replaced 1 or 2 in my time because they stopped working.
I have supplied piles of standard relays.

The PID's I use provide a fixed voltage to the SSR (24vdc) even though the SSR can operate normaly between 3vdc and 30 vdc.

[dragon813gt]

I use mine on a smoker but it controls the heating element. I don't bother this time of year because the smoker barely makes temp as it is. I have the P, I and D values written down for the smoker and lead pot. Takes a few seconds to change them manually when switching between the two. It goes w/out saying that they have dedicated thermocouples.

[HATCH]

Sig, if you need a Thermocouple for your project, I got a bunch of wrong temp ones (for my applications) and I can send you one for shipping cost.
Its 4 inch and rated for 752F.
That should be hotter then your smoker will be.

CHARLES