Pre-planning stages of BCS based homebrewery

Suggestions, Problems, Availability, etc. Everything is up for discussion.
pngaudioguy
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Re: Pre-planning stages of BCS based homebrewery

Post by pngaudioguy »

Coincidentally, our offer just got accepted on a house today. It has 875 square feet of unfinished basement that's 7.5 feet tall. Brew space confirmed.
pngaudioguy
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Re: Pre-planning stages of BCS based homebrewery

Post by pngaudioguy »

Ok, JonW - you're right. Extra physical PID's is crazy. I do like the idea of having something as a backup, though. I also like the idea of all the switching being done on the 5V side, so it occurred to me to use a 5V PWM "motor controller" that has a variable duty cycle as my backup. WAY cheaper for something that will hopefully never get used, while still providing more than just on/off control. http://www.amazon.com/Voltage-Motor-Spe ... B00OMWW7FS

That will need a 5V power supply, as will the manual mode pump switch and the power for the proximity sensors for element safety. I'm thinking something along this line should be appropriate: http://www.amazon.com/dp/B008DFCOW6/. I'd originally thought about wiring the fluid level proximity sensors into DINS of the BCS, but I think I like the idea of them controlling a relay instead. That way, the only way for voltage to exist on the element is if the SSR fails - which now that I mention it I'll probably adjust for V2. Put the safety relay in the contactor trigger circuit instead of the SSR control circuit... That way if the liquid level isn't high enough, the element can't possibly get power at all, even if the SSR fails.

I picked up a copy of Visio and got to sketching my wiring diagram. Version 1 follows. I'm sure I'm missing something. The BCS, network device, and possibly a touch screen TW700 or similar will live in a separate enclosure. The low voltage stuff is all separated from the high voltage, and in addition to paying attention to my grounding scheme, the connection between the temp sensors and DB25 connector will have a physical metal barrier separating it from the rest of the high voltage enclosure.

Because the BCS lives in a separate enclosure, I've put the E-Stop button in the loop with the key that enables/disables power to the entire circuit. Also, it makes sense to toss the "power is live" Pilot in that same circuit to me.

Proposed circuit wiring (pictoral elements stolen from ebrewsupply since everyone is familiar with their diagrams):
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Proposed panel layout:
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pngaudioguy
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Re: Pre-planning stages of BCS based homebrewery

Post by pngaudioguy »

Here's how the plugs will fit on a 16"x12"x8" enclosure. Definitely the minimum size to go with when using these enormous power connectors!
Image
clearwaterbrewer
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Re: Pre-planning stages of BCS based homebrewery

Post by clearwaterbrewer »

pngaudioguy wrote: I do like the idea of having something as a backup, though.
you you want a backup, just go super simple and build a box with a potentiometer driven SSR (stilldragon DIY controller, for example) for your element and a couple outlets driven by household light switches... basically a starter e-brew system ;-)
pngaudioguy
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Re: Pre-planning stages of BCS based homebrewery

Post by pngaudioguy »

That's basically what my backup is when you flip the switches to manual mode. Except instead of building a second box with another copy of all the expensive bits (SSR's, 63A disconnects, etc), I'm just planning to have a 3 way switch and a PWM with a knob that live in the same box.
BrunDog
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Re: Pre-planning stages of BCS based homebrewery

Post by BrunDog »

I didn't do an exhaustive look, but extra PWMs doesn't make sense to me... how mission critical is making beer anyway? I think you will introduce more failure opportunities with all the extra switches and contactors... but that's just my personal opinion. Also, you had better check the pulse with of the PWM and the switching speed of the SSR. It is possible the PWM controller is too fast for the SSR. I think a key switch and E-stop on the same line are superfluous. And BTW, that power pilot light is not wired correctly - It likely won't work series with the switches (won't light and the contactor won't close). I would tie it in parallel with the to terminal legs. Also, make sure the single pole relay coils can be driven directly by the BCS outputs. They would need to be 5V and <300mA and should have dump diodes.

-BD
BrunDog
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Re: Pre-planning stages of BCS based homebrewery

Post by BrunDog »

clearwaterbrewer wrote: you you want a backup, just go super simple and build a box with a potentiometer driven SSR (stilldragon DIY controller, for example) for your element and a couple outlets driven by household light switches... basically a starter e-brew system ;-)
+1

-BD
pngaudioguy
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Re: Pre-planning stages of BCS based homebrewery

Post by pngaudioguy »

Good catches, BD.

I wasn't thinking clearly when I thought, "Hey I can throw the Power indication in here and simplify the wiring..." uh, not so much. The key and E-Stop are on the same circuit for different reasons. The key switch is to prevent my kiddos from firing up the brew rig without me around when they get a couple years older and possibly damaging something / electrocuting someone. The E-Stop is for me if I'm brewing and something goes haywire - quick slap, the whole thing goes dead. Since the BCS will live in a separate enclosure, and the sensors will continue to pass data with the box off, I don't lose my "control circuit" just the output end of the system by killing this enclosure.

Also, good point on the switching speed of the SSR. I need to check that, since I don't know the answer. If not, I'll just wire my own up using a 555 chip, but figured that for ~$6, the lazy route sure is easy... Beer making is "mission critical" enough to me that if something craps out in the software, I don't want to spend 30-45 minutes messing around with it figuring out how to get reconnected to move to the next stage. I'd rather just flip to manual mode and maintain or adjust to the next temperature. If I have time at that point of the brew process to fool around with resetting devices, finding them on the network, finding and/or reloading my process and recipe variables if necessary, and loading the next stage, then I'll do that and flip back to "Auto" to let the precision kick in.

Whether or not I use switches, I'm putting 3 contactors in there. A main, and one for each heating circuit (because they're cheaper than relays for the same amperage.) If I don't use a switch, then I'll need to use extra outputs off the BCS to trigger the relays to open those contactors. (2 extra channels of BCS out, 2 extra channels of relays.) One area I refuse to compromise is electrical safety. I only want electrical power present at the plugs when I specify for it to be there, and I'm not a fan of the this circuit is always active unless the other one takes over approach, which would be how to get by with just one BCS output to accomplish that.

The relays, despite being drawn scattered all over the schematic will be on one of those Electronics-Salon eBay seller relay boards that draw .35mA at 5V by using Darlington transistors, etc. As drawn, needing 5 would mean get the 8 channel board.
BrunDog
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Re: Pre-planning stages of BCS based homebrewery

Post by BrunDog »

That's a nice board. Should I need more outputs I might consider same - thanks!

-BD
pngaudioguy
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Re: Pre-planning stages of BCS based homebrewery

Post by pngaudioguy »

Yeah, the specs on those boards seem pretty reasonable, and several of the regular contributors here have spoken highly of stuff from that vendor. I like the price of the 4 channel a lot better, but need that fifth relay for the way I want to set it up... Never hurts to have extras floating around for possible later additions :)

Played with Sketchup and Visio a bit more today. Fun stuff. Really chomping at the bit to get started building, but that has to wait until after the house move.

Schematic v2:
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Interior 3D v1:
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