Pid versus ssvr

[nealm]

Can anyone compare and contrast the use of a PID in manual mode versus a potentiometer controlled solid state variable relay (SSVR) to control the heating element of a BK? As I see it the ssvr's analog control might be easier to tune than the pid's digital feature.
I am in the ruminating stage of a e-brewery since my aging back is protesting lifting heavy container of liquid.

 

[Cevan]

Lots of people use the PID to controll boil so its pretty much tried and true. The SSVR will offer much tighter control but in the end were just boiling wort right. I guess the PID would have the benefit of temp monitoring and alarms, not that it's really necessary in the boil kettle but convenient.

 

[jeffmeh]

With an SSR, you can keep it automatic and set an alarm for just below boiling (say 210F at sea level), leave it, and not worry about boilovers. When the alarm sounds, set to manual and dial in your temperature. You also have the ability to use the device for automated temperature control for mashing, sous vide, and the like, if you wish.

The only advantage to an SSVR in this application is that you have an analog dial, if that is important to you.

 

[kal]

+1 to what jeffmeh said.

I use a PID for my boil but did consider an analog style dial to go from 0-100% boil duty cycle.

At the end of the day I found it would limit what I could do like:

- Boilover alarming: With the PID running in manual at 100%, I set the alarm to 208F to warn Me that I'm approaching boil. I use this all the time as the PID's #1 alarm is set to 208F all the time. All I need to do is turn the boil PID alarm switch from OFF to ON. When it sounds I know that I'm very near boil so I start stirring/paying attention. If you really want good control or are afraid you might be out of the room at the time, set the PID to AUTO mode instead and set the temp to 208F. This way you'll heat up to 208F and stop and the alarm sounds. You then switch to manual 100% and stir, watching the boil carefully.

- Multi-temp Hop Stands: I didn't even know these existed when I designed my setup but they've come in handy like when I brewed by Hop Stand Pale Ale that only has hops after the boil, steeped at different temperatures for 80 minutes. The boil PID is set to whatever temp I want to steep at and it's held.

The analog dial has the advantage that it's quicker to adjust, but other than going from 100% (to get to boil) to 85% (while boiling), I never adjust it. I don't use different amounts of duty cycle, ever.

Kal

 

[MercMan]

With an SSR, you can keep it automatic and set an alarm for just below boiling (say 210F at sea level), leave it, and not worry about boilovers. When the alarm sounds, set to manual and dial in your temperature. You also have the ability to use the device for automated temperature control for mashing, sous vide, and the like, if you wish.

The only advantage to an SSVR in this application is that you have an analog dial, if that is important to you.

Personally, I like the dial. I can turn it full on until I reach boil then watch the boil as I adjust the dial to exactly where I want it to be. There is nothing simpler.

Also, I tried boiling with my PID just to see how it would work and it did not reach boil as fast as my SSVR did. The PID cycled on & off more & more as it got closer to boil. I figure the off time just extended the time to boil. My PID is a CXTG-3000 if this makes a difference & it does a great job with my mash.

 

[alien]

I have decided to go with both. For each element I have a Manual/Off/Auto switch that selects between PID control and a manual power setting controlled by PWM. I just prefer the rotary dials to keying in a %. But if your PID controller has manual power control it's gilding the lily, really.

 

[MercMan]

Since you have both in one setup please let us know which one you like best for boil.

 

[Red Clay]

I have decided to go with both. For each element I have a Manual/Off/Auto switch that selects between PID control and a manual power setting controlled by PWM. I just prefer the rotary dials to keying in a %. But if your PID controller has manual power control it's gilding the lily, really.

I'd also like my "Manual" switch to be set by a rotary dial. Do you mind sharing your solution for setting the duty cycle? Did you use a DIY 555 circuit?

I'd love to find an inexpensive prebuilt rotary pwm controller!

 

[MercMan]

There was one on eBay but I don't know how well they work.

 

[MercMan]

I found the eBay part.
http://www.ebay.com/itm/10000W-220V...736?pt=LH_DefaultDomain_0&hash=item5af4be15b0

 

[alien]

Both the PWM cycle and the PID are controlled by an Arduino-type microcontroller, similar to the brains of a BrewTroller. A 555 would work perfectly well, though.

The closest thing to off the shelf PWM controller would be a cheap LED dimmer, with one of the capacitors replaced to give a slower cycle, governing an SSR. I have done just this and at some point I will get around to posting a tutorial.

In the mean time if anyone out there has $10 and wants a hacked dimmer just PM me and I'll post it anywhere in the USA, satisfaction guaranteed.