Pagey
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Joined: Sun Jul 21, 2019 2:29 am

I am establishing a craft brewery and using PID temperature controllers

Sun Jul 21, 2019 2:51 am

G'day all.

So I have never used a Pi in the past but I find myself in a circumstance where I may have a genuine use for one. I am establishing a craft brewery and using PID temperature controllers. These controllers have alarm points that I actually wish to use if possible.

Physically, the temperature controller has 3 contacts, call them A, B and C. A & B are connected electrically while no alarm is sounding. When the alarm sounds the contacts change to A & C.

So could I use a break in circuit or a connection in circuit between pins on the PI to trigger an action in the PI? Say sending a simple - predefined email via a wifi module? I only need to listen for alarms on 5 controllers so I am assuming I would need 10 pins on the PI and I think there are enough for that?

Now I would have of course used the forum's search function but I honestly have no idea what to search for I am that much of a noob. So apologies in advance!

Andyroo
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Location: Lincs U.K.

Re: I am establishing a craft brewery and using PID temperature controllers

Sun Jul 21, 2019 2:45 pm

Welcome to the forum.

Do these alarm point have any voltage on them or are they basically a switch?

I would look to use opto-isolators for anything connected to commercial equipment as it save argument with maintenance companies who refuse service as ‘it’s your equipment at fault not ours’ - not that I have ever had that discussion :roll:

If it’s just acting as a switch then you could use the Pi 3v3 line (NOT 5V) to the ‘A’ point and just route the ‘C’ point back to the Pi with one pin per alarm. I would be tempted to route the ‘B’ back so you know there is no alarm as well but that could be second phase when you put a nice web server up to show status :lol:

The Foundation have published a book (free PDF or print copy available) at https://www.raspberrypi.org/magpi/issue ... o-zero-v1/ that shows you how to wire up switches / push buttons as a starting point.

Sending email is straightforward if you have an email account with a company (or your own email server) or you can use a free Google account. A recent thread here covered getting mail running on Buster (the latest version of the Pi operating system).
Need Pi spray - these things are breeding in my house...

PhatFil
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Location: Oxford UK

Re: I am establishing a craft brewery and using PID temperature controllers

Sun Jul 21, 2019 7:44 pm

sounds like the 'alarm' is simply the output of a standard relay offering you COM, NC and NO terminals.
(sestos, inkbird or auber pid perhaps?)
in which case you can simply wire the COM terminal to either 3.3v or gnd and the NO terminal to a suitable gpio for your pi s/w to monitor, a pull up or pull down resistor to pull the gpio pin to the known OFF position may help avoid false positives..

Some pids will push out a 12v alarm signal which if connected to your pi would fry it in an instant.
So check manuals and docs for your model diligently first.


However a pi is a bit overkill for such a job, personally i would use something like an esp8266 dev board like a wemos d1 to raise an email alarm on a given input..

I cant imagine you leaving anything on the hot side unattended so if its for fermentation control perhaps brewpi- or brewpi-less could be worth checking out too..
https://github.com/vitotai/BrewPiLess

And then at the top of the range there is also the smartpid ;) http://smartpid.com/

Pagey
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Joined: Sun Jul 21, 2019 2:29 am

Re: I am establishing a craft brewery and using PID temperature controllers

Mon Jul 22, 2019 5:20 am

Great info thank you guys. And yes it's all cold side.

Inkbird PID and have been through the destruction manual and it certainly seems as if it's designed to make or break a circuit rather than put out a signal. The idea of feeding it a +V is a great one!

I did not even realise there were lesser versions of the Pi that could be obtained but absolutely if they are cheaper and still do the same job then why not!

I have some good reading to do and there will undoubtedly be more questions in the near future once I have a little understanding of what's going on here.

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Gavinmc42
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Re: I am establishing a craft brewery and using PID temperature controllers

Mon Jul 22, 2019 5:41 am

I use B+ and Zero's for temperature controllers, down to < 0.5C controlling.
They have way too much processing power for that, but Zero's are cheap ;)

Depends it you want Ethernet system or WiFi .
Plenty of left over CPU grunt to add a web page server for monitoring.

Software wise lots of choices, probably too many.
Others have done beer brewing with Pi's, start there?
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

Andyroo
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Joined: Sat Jun 16, 2018 12:49 am
Location: Lincs U.K.

Re: I am establishing a craft brewery and using PID temperature controllers

Mon Jul 22, 2019 6:27 pm

Gavinmc42 wrote:
Mon Jul 22, 2019 5:41 am
...
Others have done beer brewing with Pi's, start there?
I know the new 4s run hot - but this hot?

Not allowed to drink with my tablets - could murder a nice ice cold larger about now :cry:
Need Pi spray - these things are breeding in my house...

PhatFil
Posts: 1309
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: I am establishing a craft brewery and using PID temperature controllers

Mon Jul 22, 2019 7:17 pm

For cold side control/monitoring may i suggest you check out these proven projects.

#1 the stc1000+ a multi stage ramping FV temp control firmware upgrade for the ubiquitos stc1000 controller.

https://github.com/matsstaff/stc1000p

No wifi/net capacity but that can be added (see the 433mhz enhancement) but is redundant if used with:-

#2) The ispindel a wifi real time hydrometer to publish temp and abv metrics for a brew live.
https://github.com/universam1/iSpindel

having followed both projects through to completion i can assure you they are both complete projects,
even tho the stc1000+ github page has not been updated for over a year the hack has been live for probably a decade..

Use stc1000+ modules to control your fv temps and ispindels to monitor conditions and publish the data for consumption by your Pi via mqtt ;) then you can raise any alarm email message you like..


the pita component for the ispindel build is the PET geo-caching bottle used as the foodsafe container/float. these i had to import from germany with a postage cost higher than the bottle cost!
the 3d printed sled is an optional aspect. but would

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