PID Controller for. Mash Tun

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charliemartin
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PID Controller for. Mash Tun

Post by charliemartin » Thu Apr 19, 2018 5:01 pm

Hi,
Looking for some help from the electrical experts on here. I currently have a self-built re-circulating mash tun. The temperature is controlled by a 30 amp STC 1000 connected to an NTC temperature probe with 3 connections. (only 2 connected on STC).
The STC doesn't do as good a job of controlling the mash temp as I would like and the LED display is starting to fail, so I was thinking of replacing it with a PID.
However, I have no idea what PID to get. I believe I will need an SSR as well and maybe a heatsink.
Can anyone point me in the right direction, please?

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Fil
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Re: PID Controller for. Mash Tun

Post by Fil » Thu Apr 19, 2018 5:22 pm

If looking at the cheaper end of the market, the sestos brand conform fairly closely to the auber brand which means you can read the well written manual for the auber pids and since the sestos firmware copies it (different values for settings can apply and the sestos is a Celsius using unit only)
you can gain understanding from the auber manual and then check settings in the taables on the sestos sheet (yes a single largish sheet of paper!!)
https://www.auberins.com/images/Manual/ ... %201.0.pdf
fwiw i opted for a sestos brand pid. when looking the rex brand got a lot of bad press, tho that could have been something to do with folk buying non ssr models intended for use with mechanical relays??

Inkbird were not around so much when i was looking, since they are active in some brew forums (thbf if your allowed back hehe) providing regular give aways and offering some support if needed. So the inkbird pids may be worth looking at too, afaik they too bear similarity to auber firmware?

SSR s folk tend to use SSRS rated at least 2x the draw expected.. Using a 3kw element (upto 13a) im using a 25a SSR ..
I have taken readings of the temperature of the heatsink (centre) when heating up 60l in the hlt and it was circa 60C and got hotter so Yes a heatsink will be needed and if inside a case fans too probably at least good ventelation holes.. so perhaps think externally mounted heatsinks??

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Re: PID Controller for. Mash Tun

Post by jaroporter » Thu Apr 19, 2018 6:16 pm

fil probs knows.. which pid allows charlie to keep the same ntc probe? I know the inkbird (sestos rebrand?) doesn't allow for them so a new pt100 probe would be needed. may or may not be a consideration depending on if it's a badass footlong SS NTC probe or not.. :p
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charliemartin
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Re: PID Controller for. Mash Tun

Post by charliemartin » Thu Apr 19, 2018 7:10 pm

jaroporter wrote:fil probs knows.. which pid allows charlie to keep the same ntc probe? I know the inkbird (sestos rebrand?) doesn't allow for them so a new pt100 probe would be needed. may or may not be a consideration depending on if it's a badass footlong SS NTC probe or not.. :p
It's a 300mm NTC from Brewbuilder.

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Re: PID Controller for. Mash Tun

Post by charliemartin » Thu Apr 19, 2018 7:17 pm

Inkbird were not around so much when i was looking, since they are active in some brew forums (thbf if your allowed back hehe) providing regular give aways and offering some support if needed. So the inkbird pids may be worth looking at too, afaik they too bear similarity to auber firmware?


Hi Fil,
Thanks for the info. I was looking at Inkbird PIDs, but no idea which to go for. Would like to retain my NTC temp probe if possible.
Curious about your comment re. THBF though?


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Re: PID Controller for. Mash Tun

Post by jaroporter » Thu Apr 19, 2018 7:18 pm

yup that's the one I was thinking of!

just outta interest which variable(s) are you controlling and how?
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charliemartin
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Re: PID Controller for. Mash Tun

Post by charliemartin » Thu Apr 19, 2018 7:23 pm

jaroporter wrote:yup that's the one I was thinking of!

just outta interest which variable(s) are you controlling and how?
The STC 1000 is heat only, so I set it to the required mash temp and it switches the element on or off in my Cygnet boiler (mash tun). It has worked reasonably well up to now, but it tends to overshoot the temp so I would like a bit more control which I believe a PID would give.

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Re: PID Controller for. Mash Tun

Post by PeeBee » Sat Apr 21, 2018 10:17 am

charliemartin wrote:
Thu Apr 19, 2018 7:17 pm
... Curious about your comment re. THBF though?
Fil seems to have missed this? I'll sort of answer it...

The comment isn't so relevant on this forum. Register on this forum: http://forum.craftbrewing.org.uk/index.php. Post a message saying "I'm a keen supporter of THBF. Can any of you help me with a brewing problem?". You should get an answer? Make sure you are wearing your chainmail underpants before doing this.

And do remember what curiosity did for a cat.

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Re: PID Controller for. Mash Tun

Post by chefgage » Sat Apr 21, 2018 11:21 am

Edited

This is the type i have used coupled with a SSR and heat sink. If you get one make sure it has a SSR output. The same model number is used for both relay and SSR output

Image
Last edited by chefgage on Sat Apr 21, 2018 4:25 pm, edited 1 time in total.

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Re: PID Controller for. Mash Tun

Post by PeeBee » Sat Apr 21, 2018 1:45 pm

chefgage wrote:
Sat Apr 21, 2018 11:21 am
This is the type i have used coupled with a SSR and heat sink. If you get one make sure it has a relay output. The same model number is used for both relay and non relay output ...
Whoops. Bit of contradiction with preceding posts.

But does show people can be happy with thier "Rex" PIDs. I don't, or ever have, owned one so make no further comment on 'em.

The comments about "make sure it has a relay output" are confusing. Surely PIDs have relay output or (low powered) SSR output? But you are using SSRs.

If you use relay output you should have the PID configured to be fairly slow - rapid switching a mechanical relay will quickly knacker it. If the PID is configured to switch rapidly you use SSRs (solid-state relays). You also use SSRs for switching fairly heavy loads (like electric elements) which are rated too high for a mechanical relay (in the UK we have something called a "contactor" which is effectively a heavy switching relay which reduces sparking and the radio interference that causes, and perhaps reduces potential for fires, and probable other reasons that haven't crossed my radar). Generally we (home-brewers) use fast-switching SSRs, but could easily get away with slow switching relays if we really wanted (our systems are relatively slow; we just don't like to believe that). PIDs can often be configured to use mechanical relays with an "on/off" mode to reduce the stress on a relay.

SSRs are not designed to "fail safe". So you often see the power to the element switched on with a "contactor" and fine-tuned with a PID controlled SSR.

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Re: PID Controller for. Mash Tun

Post by chefgage » Sat Apr 21, 2018 4:14 pm

PeeBee wrote:
Sat Apr 21, 2018 1:45 pm
chefgage wrote:
Sat Apr 21, 2018 11:21 am
This is the type i have used coupled with a SSR and heat sink. If you get one make sure it has a relay output. The same model number is used for both relay and non relay output ...
Whoops. Bit of contradiction with preceding posts.

But does show people can be happy with thier "Rex" PIDs. I don't, or ever have, owned one so make no further comment on 'em.

The comments about "make sure it has a relay output" are confusing. Surely PIDs have relay output or (low powered) SSR output? But you are using SSRs.

If you use relay output you should have the PID configured to be fairly slow - rapid switching a mechanical relay will quickly knacker it. If the PID is configured to switch rapidly you use SSRs (solid-state relays). You also use SSRs for switching fairly heavy loads (like electric elements) which are rated too high for a mechanical relay (in the UK we have something called a "contactor" which is effectively a heavy switching relay which reduces sparking and the radio interference that causes, and perhaps reduces potential for fires, and probable other reasons that haven't crossed my radar). Generally we (home-brewers) use fast-switching SSRs, but could easily get away with slow switching relays if we really wanted (our systems are relatively slow; we just don't like to believe that). PIDs can often be configured to use mechanical relays with an "on/off" mode to reduce the stress on a relay.

SSRs are not designed to "fail safe". So you often see the power to the element switched on with a "contactor" and fine-tuned with a PID controlled SSR.
Not really a contradiction but more of me talking nonsense :)

I meant to say some of the rex type pid controllers marked as c100 only have a relay output but some have an output suitable for an SSR. So depending on your application you need to get one to suit. I did read people having problem with the rex type but i have always found them to be reliable.

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Re: PID Controller for. Mash Tun

Post by chefgage » Sat Apr 21, 2018 4:23 pm

chefgage wrote:
Sat Apr 21, 2018 4:14 pm
PeeBee wrote:
Sat Apr 21, 2018 1:45 pm
chefgage wrote:
Sat Apr 21, 2018 11:21 am
This is the type i have used coupled with a SSR and heat sink. If you get one make sure it has a relay output. The same model number is used for both relay and non relay output ...
Whoops. Bit of contradiction with preceding posts.

But does show people can be happy with thier "Rex" PIDs. I don't, or ever have, owned one so make no further comment on 'em.

The comments about "make sure it has a relay output" are confusing. Surely PIDs have relay output or (low powered) SSR output? But you are using SSRs.

If you use relay output you should have the PID configured to be fairly slow - rapid switching a mechanical relay will quickly knacker it. If the PID is configured to switch rapidly you use SSRs (solid-state relays). You also use SSRs for switching fairly heavy loads (like electric elements) which are rated too high for a mechanical relay (in the UK we have something called a "contactor" which is effectively a heavy switching relay which reduces sparking and the radio interference that causes, and perhaps reduces potential for fires, and probable other reasons that haven't crossed my radar). Generally we (home-brewers) use fast-switching SSRs, but could easily get away with slow switching relays if we really wanted (our systems are relatively slow; we just don't like to believe that). PIDs can often be configured to use mechanical relays with an "on/off" mode to reduce the stress on a relay.

SSRs are not designed to "fail safe". So you often see the power to the element switched on with a "contactor" and fine-tuned with a PID controlled SSR.
Not really a contradiction but more of me talking nonsense :)

I meant to say some of the rex type pid controllers marked as c100 only have a relay output but some have an output suitable for an SSR. So depending on your application you need to get one to suit. I did read people having problem with the rex type but i have always found them to be reliable.
For the occasional home brew session these i have found to be ok to use. If i was designing a electrical system at work i would of course not be using a £12 rex pid :) with regards contactors and reduced sparking you have just reminded me about many years ago entering a substation to work on a system. This was before the more modern closed contactors were used. There was a wall full of open type contactors all clacking and arcing away like something out of frankensteins laboratory :)

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Re: PID Controller for. Mash Tun

Post by PeeBee » Sat Apr 21, 2018 7:43 pm

chefgage wrote:
Sat Apr 21, 2018 4:23 pm
... If i was designing a electrical system at work i would of course not be using a £12 rex pid :) with regards contactors and reduced sparking you have just reminded me about many years ago entering a substation to work on a system. This was before the more modern closed contactors were used. There was a wall full of open type contactors all clacking and arcing away like something out of frankensteins laboratory :)
Yikes! I've never had to experience why we use modern contactors, but I am reassured by the enormous "clunk" they make when operated.

What does worry me is the willingness of home-brewers to knock up an "Electric Brewery" design based on the popular published build instructions from the States. You often come across people trying to build these looking for "32 amp relays".

Eek! :wall

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Re: PID Controller for. Mash Tun

Post by charliemartin » Sat Apr 21, 2018 9:49 pm

chefgage wrote:Edited

This is the type i have used coupled with a SSR and heat sink. If you get one make sure it has a SSR output. The same model number is used for both relay and SSR output

Image
Hi chefgage,
Do you know offhand if I can use my existing NTC probe with this PID?
Also would like to know best place to purchase.

Cheers,
Charliemartin

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Re: PID Controller for. Mash Tun

Post by chefgage » Sun Apr 22, 2018 2:39 pm

charliemartin wrote:
Sat Apr 21, 2018 9:49 pm
chefgage wrote:Edited

This is the type i have used coupled with a SSR and heat sink. If you get one make sure it has a SSR output. The same model number is used for both relay and SSR output

Image
Hi chefgage,
Do you know offhand if I can use my existing NTC probe with this PID?
Also would like to know best place to purchase.

Cheers,
Charliemartin

Sent from my LG-H870DS using Tapatalk
Unfortunatly the rex type (certainly the ones i have used - rexc100) do not accept NTC inputs. They have a thermocouple and RTD input. I use RTD's to measure temperature which of course use resistance to measure temperature the same as your NTC probes. The problem with the NTC probe is a decrease in resistance gives you an increase in measured temperature. The RTD is the opposite i.e. an increase in resistance gives you an increase in measures temperature.

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