Stevevliet

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I have been borrowing a friends equipment for a nice AG setup (propane) and I'm ready to get my own system. I'm thinking the best route is an ebrew system.

I have been doing a lot of research about an electric brewery since I have a 240V/50A setup in my garage that is not in use. There are some awesome builds on this forum and so much information that I think I'm ready to take the dive into this project.

I was wondering if anyone has ever built one of these systems using 1 pid shared between 2 elements (4500W?) using a selector switch. I'd like to see a wiring diagram for this system and any suggestions or pitfalls with this setup. Thanks guys!

iijakii

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There's been a lot of threads recently on the subject, but the general consensus is generally it's not possible. PID differences, etc etc.

edit: apparently I have no idea what I'm talking about and shouldn't post. Heh.

wubears71

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The proportional, integral and derivative tuning parameters will be different for each temperature you are trying to control. With temperature control, derivative is used which leads to poor control if not tuned properly. So basically what you end up with in your proposed setup is one loop that controls well and another one that is out of control. Unless you had a way to pass tuning parameters into the PID loop based on what is being controlled you won't have much luck with the proposed setup.

passedpawn

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I built what you suggest. I've used it at least 50 times. One of the elements is for the HLT, the other is in the boil kettle. I only had 30A available, so it didn't really make much sense to have 2 PIDs when they could never both be active.

See here for more info. If you have questions about the schematic, which is attached in PDF form, just ask.

http://www.homebrewtalk.com/f170/240vac-toolbox-control-panel-pics-184296/

__________________
Now there's some take delight in the carriages a rolling
and others take delight in the hurling and the bowling
but I take delight in the juice of the barley
and courting pretty fair maids in the morning bright and early

wubears71

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Sweet setup. You are just using the PID controller in auto for 1 temperature, correct?

P-J

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Stevevliet,

Welcome to the forum. I hope you enjoy participating here.

What you are trying to achieve can be easily done. A single PID set up to control the temperature in a HLT and then switched to control the rate of the boil in your BOIL kettle is all you need. You will need a pump (or 2) as well.

Here is a diagram that might interest you as a starting point:

As always - click on the image to see a full scale diagram that is printable on Tabloid paper (11" x 17"):

dan6310

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Stevevilet,
I am near completion on the exact system. You run the PID in auto mode for the HLT and when time to boil, switch to manual mode and set the element on/off time as a percentage once you reach a boil.
I used PJ’s diagram he posted with minor additions of lights for the pump switch and I added a cooling fan.
Dan

shortyjacobs

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And to add to others, tune the PID on the element that you most care about accurate temp control on. Typically this means you autotune it on the HLT, since that's where exact temps matter. It might run a bit rampant with the BK, but who cares, typically you are in manual mode and cranking power into it anyway.

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(As of 10-24-2011)
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Aging - None :-(
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My invisible AG sculpture, with no actual sculpture and a tiny footprint.
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passedpawn

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Correct.

I could use in auto for both kettles, but you're right, the BK doesn't need auto mode. I tuned the PID for the HLT, and also calibrated the offset for the temp sensor for that one too.

I think the BK is within a degree or two of being correct though. I like to see that temp when I'm chilling.

__________________
Now there's some take delight in the carriages a rolling
and others take delight in the hurling and the bowling
but I take delight in the juice of the barley
and courting pretty fair maids in the morning bright and early

wubears71

Recipes 

Cool.