Dual Digital F/C PID Temperature Controller ??

Xringer · 09-20-11, 04:14 PM

Anyone here ever work with these PID gizmos?

They don't cost too much..
eBay -

And, they sound very interesting..
PID controller - Wikipedia, the free encyclopedia

I've seen were people are using these for fancy coffee makers, to keep their temperature at +/- 1deg..
I think they were using a digital pulse output to an SSR..

I've been looking at PIDs, wondering if they could be used to control the water temp,
in my boiler, by switching a ASHP off and on, (No digital pulses).

My first impression is, these PIDs are smart and learn when to shut down
early, before over-shoot comes into play.. Anyone up on these things?

Thanks,
Rich

Xringer · 09-22-11, 02:14 PM

I found some "Settings" info at this link,
DIN Digital PID Temperature Control Controller 100-240V 12VDC&Relay with Sensor | eBay

That gives me an idea of what these things do..

Here's a Plain Jane temp controller..
eBay Temp control

silverinsight2 · 09-24-11, 01:19 PM

I calibrate these things all the time at work, I've never had to replace one.

abogart · 02-02-12, 08:38 AM

I have been looking at these lately too. They are SOOOOO cheap (like $25) and have so many functions and applications. I just can't seem to find at way to integrate one of them into any of my systems. They seem to work great for on-off pulsing applications, like electric resistance heaters. At the foundry they used them to control core box temperature on the core machines. In this system the PID controlled a servo gas/air valve that had two positions: high-fire and low-fire, controlling the flame of natural gas burners. The servo valves would have been perfectly capable of any setting in between, but the PID only pulsed between the high and low settings. They did, however, seem to do a nice job of maintaining temperature.

I would like to figure out how to get a PID to control damper position. This could be a good retrofit for my woodstove, having the PID control a combustion air damper to maintain a set flue stack temperature. However, open-closed - or even high-fire, low-fire for that matter - doesn't fare too well with woodstoves. They like a consistent air supply. I have thought about finding a way to tune one to pulse a damper motor open or closed at a wide interval. I'm not sure if that would work very well, but it might be worth a shot.

These little gizmos are just too appealing not to use for SOMETHING.

Xringer · 02-02-12, 09:00 AM

If there isn't a way to program the PID so it doesn't pulse, a 555 timer could be used to stretch the pulses out..
I did that with my current (amps) controller..
http://ecorenovator.org/forum/applia...limiter-4.html

I wonder if a damper controller could be made using a model airplane RC servo?
If you can vary a pulse width, you can set a damper to a LOT of different positions..

R/C Servo Timing Waveforms - YouTube

abogart · 02-02-12, 11:31 AM

I think the real challenge lies in converting the PID's "duty cycle" into a damper position. In other words, 10% duty cycle from the PID results in 10% damper opening, and so forth. I think the easy way to do this would be to use two PIDs, One for determining how much the damper needs to be open, and the other for reading the position of the damper and determining how long and which direction the motor needs to run. I'm not sure how one would go about transmitting the duty cycle from the first PID to be ready as an input on the second PID. Unless there's another type of controller for something like that.

I think we need someone that has experience with these industrial process controls to chime in here...

Either way, it seems like the high-fire/low-fire idea might be worth playing around with. Adjusting the limits (or whatever they use) on the damper between two intermediate positions - say 25% to 75%. There is still a chance that the PID could auto-tune itself or be tuned to adjust variably. It would still probably be more efficient than leaving the damper at a single setting throughout the entire burn.

Xringer · 03-29-12, 08:56 AM

I've decided to go with a simpler device..
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

Posted about this one before..
http://ecorenovator.org/forum/sale-t...ontroller.html

It has firmware that can be used to control heat pumps. (or fish tanks)

09-20-11, 04:14 PM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Dual Digital F/C PID Temperature Controller ?? Anyone here ever work with these PID gizmos? They don't cost too much.. eBay - And, they sound very interesting.. PID controller - Wikipedia, the free encyclopedia I've seen were people are using these for fancy coffee makers, to keep their temperature at +/- 1deg.. I think they were using a digital pulse output to an SSR.. I've been looking at PIDs, wondering if they could be used to control the water temp, in my boiler, by switching a ASHP off and on, (No digital pulses). My first impression is, these PIDs are smart and learn when to shut down early, before over-shoot comes into play.. Anyone up on these things? Thanks, Rich

09-22-11, 02:14 PM	#2
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I found some "Settings" info at this link, DIN Digital PID Temperature Control Controller 100-240V 12VDC&Relay with Sensor \| eBay That gives me an idea of what these things do.. Here's a Plain Jane temp controller.. eBay Temp control Last edited by Xringer; 09-22-11 at 02:22 PM.. Reason: One more link..

02-02-12, 09:00 AM	#5
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	If there isn't a way to program the PID so it doesn't pulse, a 555 timer could be used to stretch the pulses out.. I did that with my current (amps) controller.. http://ecorenovator.org/forum/applia...limiter-4.html I wonder if a damper controller could be made using a model airplane RC servo? If you can vary a pulse width, you can set a damper to a LOT of different positions.. R/C Servo Timing Waveforms - YouTube __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

03-29-12, 08:56 AM	#7
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I've decided to go with a simpler device.. eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices Posted about this one before.. http://ecorenovator.org/forum/sale-t...ontroller.html It has firmware that can be used to control heat pumps. (or fish tanks) __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

09-24-11, 01:19 PM	#3
silverinsight2 Lurking Renovator Join Date: Sep 2010 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	I calibrate these things all the time at work, I've never had to replace one.

02-02-12, 08:38 AM	#4
abogart Efficiency Afficionado Join Date: Jan 2012 Location: Michigan, US Posts: 68 Thanks: 21 Thanked 6 Times in 4 Posts	I have been looking at these lately too. They are SOOOOO cheap (like $25) and have so many functions and applications. I just can't seem to find at way to integrate one of them into any of my systems. They seem to work great for on-off pulsing applications, like electric resistance heaters. At the foundry they used them to control core box temperature on the core machines. In this system the PID controlled a servo gas/air valve that had two positions: high-fire and low-fire, controlling the flame of natural gas burners. The servo valves would have been perfectly capable of any setting in between, but the PID only pulsed between the high and low settings. They did, however, seem to do a nice job of maintaining temperature. I would like to figure out how to get a PID to control damper position. This could be a good retrofit for my woodstove, having the PID control a combustion air damper to maintain a set flue stack temperature. However, open-closed - or even high-fire, low-fire for that matter - doesn't fare too well with woodstoves. They like a consistent air supply. I have thought about finding a way to tune one to pulse a damper motor open or closed at a wide interval. I'm not sure if that would work very well, but it might be worth a shot. These little gizmos are just too appealing not to use for SOMETHING.

02-02-12, 11:31 AM	#6
abogart Efficiency Afficionado Join Date: Jan 2012 Location: Michigan, US Posts: 68 Thanks: 21 Thanked 6 Times in 4 Posts	I think the real challenge lies in converting the PID's "duty cycle" into a damper position. In other words, 10% duty cycle from the PID results in 10% damper opening, and so forth. I think the easy way to do this would be to use two PIDs, One for determining how much the damper needs to be open, and the other for reading the position of the damper and determining how long and which direction the motor needs to run. I'm not sure how one would go about transmitting the duty cycle from the first PID to be ready as an input on the second PID. Unless there's another type of controller for something like that. I think we need someone that has experience with these industrial process controls to chime in here... Either way, it seems like the high-fire/low-fire idea might be worth playing around with. Adjusting the limits (or whatever they use) on the damper between two intermediate positions - say 25% to 75%. There is still a chance that the PID could auto-tune itself or be tuned to adjust variably. It would still probably be more efficient than leaving the damper at a single setting throughout the entire burn.