Author Topic: PID question  (Read 1379 times)

Offline Paddlinpaul

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PID question
« on: December 30, 2009, 07:42:44 am »
As I understand it, the PID varies the voltage feeding the heater element to control the temperature. Does the PID plug in between the smoke generator and the cabinet? If the main power cord plugged into the PID would it not fluctuate the speed and temp of the bisquit advancer and burner?
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Offline FLBentRider

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Re: PID question
« Reply #1 on: December 30, 2009, 07:49:59 am »
I don't know if it varies the voltage or simply turns it on or off as it needs to.

I would not plug the SG into the PID.

On an OBS, it plugs in between the SG and the Tower.
I have the cords on my OBS as follows:

Wall ->SG
SG->PID
PID->Tower

On a DBS, I think there are two wall connections:

Wall->SG
Wall->PID
PID->tower
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Offline 3rensho

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Re: PID question
« Reply #2 on: December 30, 2009, 08:15:33 am »
The PID/relay combination acts as an on/off switch.  It does not vary the voltage to the heater.  The smoke generator should never be run by the PID, just the cabinet heating element.
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Offline pensrock

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Re: PID question
« Reply #3 on: December 30, 2009, 10:10:14 am »
Thats correct when talking about the kind of PIDs used here but you can get a small SCR and run it from a PID, in that case the PID would vary the voltage or current if using a current loop to control the output to the SCR. This way instead of having an on/off type of control using an SSR where the heating element is at full power then off and back on, you vary the output to the heating element so it may only be half way on fairly steady at all times. It can increase or decrease a little at a time to hold very tight temperature control. If you were watching an amp meter connected to both controls with the on/off SSR control you would see say 10 amps then zero amps. With a SCR control it would stay where needed to maintain the proper temperature, say 4 amps.

To answer your question, the PID used here by members is on or off, the voltage to the heating element does not vary, just how long it is on or off. I'm not sure about the OBS but the digital has the smoke generator plugged into the wall and the PID plugged into the wall. The tower gets plugged into the PID. The others have you going in the right direction.