Pid Controller (rex-c100) Vs Stc-1000

[mkstalen]

So I was looking into building a DIY Sous Vide and a few of the guides mention using a PID controller like this:
http://www.ebay.com.au/itm/110834647581?ss...984.m1423.l2649

What I'd like to know is what's the difference between using one of these and using an STC-1000 like I have on my fermenting fridge.

Why would I use one over the other?

 

[iralosavic]

A PID uses algorythms to predict target temperatures based on rise/fall rates, so basically you are much less likely to overshoot the target temperature with a PID than an STC1000. Even while the STC allows a .3c within target setting, it is unable to compensate for the residual heat or cold that continues heating/cooling after the target is met. However, a PID is a bit more challenging to wire up and will require additional parts, such as a solid state relay.

 

[mkstalen]

Ah. Awesome.

Thanks.

 

[mjadeb1984]

where is the best place to get these said PID controllers, eBay?

 

[QldKev]

Thats where I ordered mine from.

If you are going the PID route,
You need a PID designed to run a SSR
You need a SSR
You need a SSR heat sink
You need a temp probe.
Then all the standard wiring and mounting


The PID as iralosavic mentioned is the smarter controller. The more thermal mass in the Heat Exchanger VS the volume of wort VS the flow of wort the more important this becomes.

My internal RIMS even with the stc-1000 has minimal overshoot, so I will be leaving it on the STC-1000
My Grpyhon HERMS (small amount of water, so small thermal mass) has a small overshoot, I will be changing it for a PID, but could be ok to leave
A larger say 5L or more HERMS would have a lot more overshoot, so I would highly recommend a PID

edit: This is the PID I ordered


QldKev

 

[Fourstar]

Put simply.

If you want precision and being able to hold at that temperature consistently I'd go fro the PID. STC while they can do the job are not built for this purpose, hence the reason why majority of us use them as fridge controllers and not mash control. They will work but wont be as accurate and have the drawbacks of overshooting as noted above.

 

[seamad]

Got mine from auber instruments in US. Also sell SSR heatsinks etc

 

[kymba]

consider making your pid portable so you can use it to cook your food and control your mash (not at the same time though). a ramp / soak PID will automagically control your mash steps...you do need to step mash meat though, right

i have a similar model to the one you linked to, it has the 12v relay output rather than the internal 240v 3A relay - you would only be able to control a 720W element / load, rather than trigger one externally

i also swapped the k-type thermocouple to a PT100 probe and changed the resolution to measure / display to 0.1 degree increments - make sure you keep the instructions that come with it to get into the proper menu (even though they'll be in chinese)

 

[kjparker]

edit: This is the PID I ordered


QldKev

I looked at those kits, but when I worked it out, it was cheaper (slightly) for me to buy the parts separately, same pid, same ssr, but order a pt100 instead of the ktype probe.

In my application I want to put a plug on the end of the probe for ease of removal for cleaning of vessels, and with a k type that can be chellenging, a pt100 should not be a problem.

 

[Yob]

edit: This is the PID I ordered


QldKev

In the middle of thinking about ******* with something that aint broke -_-

Thinking of putting in a PID for the HERMS, the STC has been doing stunningly for the bit of kit that it is with minimal over/undershoot ( ± 0.4'c at the beginning, less naturally as it gets up to temps)

Question is what does the "5. accuracy ±0.2%FS" relate to as I note that above it "4. Indication and control accuracy 0.1℃, high measurement "

​If it can be controlled to 0.1'c I'm sold, as a 0.2'c swing is just that much nicer than a ±0.4'c variation...

Not unhappy with the beer the system currently produces it's just a bit hands on which until now I liked about it, would just be nice to be able to flick it on and go out to do things with the bub and come back to a brew thats mashed out.

 

[billygoat]

That means that it has an accuracy of + or - .2% of full scale.
IE - if full scale measurement is 200C, the accuracy of the measurement will be + or - .2% of the 200.
Thats assuming that the temp probe you are using is accurate, they do vary a bit.
By the way, you can still get overshoot with a PID controller. It depends how they are tuned, they have an auto tune function that works well but don't expect miracles.
The thing about a PID controller is, it may overshoot once or twice approaching its set point, but then it will hold that set point spot on for the rest of the time without undershoot or overshoot.

 

[Camo6]

I went from a .3 - .4C swing with my stc1000 to a .2C swing using a PID. Not much of a difference (although I haven't ran another autotune since changing my sparge arm and flow rates so suspect I could reduce it further).
For me the kicker is definitely having the ramp/soak function and 30 programmable steps. To be able to step mash a dry ale or a weizen at the press of a button and walk away for 90 odd minutes really helps for a less demanding brewday. Add the end of the mash it will hold at mashout temps till I start the sparge. Love it.

 

[vr4king]

Another thing to seriously consider is the current switching abilitys of both......I feel way more comfortable switching high current drawing elements with a SSR as opposed to a STC-1000 I'd hate to have STC relay fuse shut and melt down on me.......I deal with a lot of temp control instruments at work and always use PID's to control high current heater elements.

I run PIDs on my brew rig and STC's on my fermtent and keg controllers

 

[QldKev]

In the middle of thinking about ******* with something that aint broke -_-

Thinking of putting in a PID for the HERMS, the STC has been doing stunningly for the bit of kit that it is with minimal over/undershoot ( ± 0.4'c at the beginning, less naturally as it gets up to temps)

Question is what does the "5. accuracy ±0.2%FS" relate to as I note that above it "4. Indication and control accuracy 0.1℃, high measurement "

​If it can be controlled to 0.1'c I'm sold, as a 0.2'c swing is just that much nicer than a ±0.4'c variation...

Not unhappy with the beer the system currently produces it's just a bit hands on which until now I liked about it, would just be nice to be able to flick it on and go out to do things with the bub and come back to a brew thats mashed out.

I think the details about the accuracy has been answered. The topic about being able to do multiple steps has not. The Sestos in the link wont allow that. You need to look at one of the programmable options; Auber programable pid, matho's controller, of one of the awesome web based solutions we can get.

 

[Yob]

It's those small degrees of precision that I'm after, that and the ability to step mash from 10km away

 

[Mardoo]

Is it time to say the B word Yob?

 

[Yob]

B word? Not the one you're thinking of mate.. Not yet but I wanna get in first

 

[Cocko]

In the middle of thinking about ******* with something that aint broke -_-

Be positive mate, it is because you can!!

I am with Cam, the ability of the ramp/soak - set and forget is a great asset to have on brew day. If you know your recirc is not gonna block, which I am sure it has never before so why now? You can walk away and spend some time with kids or in your case weigh hops

That said, I never ran an STC as a controller but I know it would **** me manually changing, timing and being there the whole mash for something I could have spent a little extra on to run the show.

Do it = 2c.

 

[Yob]

Be positive mate, it is because you can!!

I am with Cam, the ability of the ramp/soak - set and forget is a great asset to have on brew day. If you know your recirc is not gonna block, which I am sure it has never before so why now? You can walk away and spend some time with kids or in your case weigh hops

That said, I never ran an STC as a controller but I know it would **** me manually changing, timing and being there the whole mash for something I could have spent a little extra on to run the show.

Do it = 0.2'c.

FTFY

 

[Eagleburger]

incase you havent seen it.

http://www.homebrewtalk.com/f51/stc-1000-pi-mash-control-firmware-487104/