pid controller

[Magnu420]

ok ive read on HD forums about power controllers and a lot seem to
mention about pid controller,one or two seemed to get flamed for it
and get told to look for either phase angle controller,triax,ssr and pot
and look in the relevant section for that of contoller,but why cant you use
a pid controller,why has it gotta be the other types,is it it can be controlled
better or is the pid too accurite

[Capt-Cudellez]

It depends what you are using the controller for. You can't control the power going to the still based on temp, as this is constantly changing as the ABV of the wash changes thruought the run.

You can use a PID to work a solonoid on an LM take off, this is called EARC, electronic automatic reflux control, but the power to the boiler should still be constant.

If its a power controller you are after, knowing the watts being pulled is waaay more useful than knowing the temp,

Tell us a little more about what your thinking of using it for.

[Magnu420]

I was asking a mate who is into electronics and that and
asking him if he had any ssr ie ask me what I was making
I told him a power controller he said I be better of with
a pid controller rather then a ssr and pot as I be able to control
it better but I couldn't give him a answer why a pid won't do
although I seen the reason on hd forum and couldn't find it
to show him

[Capt-Cudellez]

A PID would be the ideal choice if you are needing to hold a temperature, so say in an all grain mash, you want to hold at a specific temp for a period of time where the heat is cycled on and off to achieve this.
This is not how you run a still, temp of the boiler will rise as you progress so the PID would effectively kill the power mid run.

Where you could use a PID, would be in a CM condenser control to cycle the cooling, which again is something where you are trying to hold a temperature in a narrow range, but you would still be supplying the boiler with a constant power setting in this scenario, and your boiler temp would be constantly changing (increasing).

PID are great for control, just not for heating control when running a still. Hope that makes sense.

[Magnu420]

I did find the answer on hd by pintoshine I've shown mate
that post he made now mate got a better understanding
of why you can't use a pid controller
Cheers capt