Control Panel Design

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fluxgame

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I'm working on putting together a single-vessel electric BIAB/RIMS brew system. Of course, here I am thinking I'm all original with this idea and come to find that there are already several people using systems similar to this. I've got a Bayou Classic 62qt stock pot (with steamer basket) and am hoping to eventually get it all outfitted with tri-clamp fittings. That's a topic for another post though. For now, I'm just working on getting a control panel designed and built. I'm definitely not breaking any new ground here, but I thought I'd post up my control panel mockup, schematic and parts list for comment and critique.

control panel schematic.png

Parts:
1/16 DIN PID Temperature Controller (SSR control output) (http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=3)
40A SSR w/ Heatsink (http://cgi.ebay.com/Solid-State-Relay-SSR-24-480V-AC-40A-Heat-Sink-/370412367790)
30A Ground Fault Interrupt with Male Plug GFI Cord (http://www.friesenelectric.com/productdetails.aspx?ID=2943)
Enclosure-8X8X6 (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=ENC-8X8X6)
NEMA L6-30 Male Plug for Element (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=L6-30P)
NEMA L6-30 Female Receptacle for Element (http://www.mcmaster.com/#7162k39/)
NEMA L5-15 Male Plug for Pump (http://www.mcmaster.com/#7162K29/)
NEMA L5-15 Female Receptacle for Pump (http://www.mcmaster.com/#7162K77/)
Panel mount connector for RTD sensor (http://www.auberins.com/index.php?main_page=product_info&cPath=7&products_id=118)
Flashing Buzzer, 110 or 240V AC. 22 mm (http://www.auberins.com/index.php?main_page=product_info&cPath=7&products_id=215)
2 Position Maintained Selector Switch for Alarm (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22PMA-2)
Green Illuminated Selector Switch for Main Power (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22PMA-I2G-120V)
White Illuminated Selector Switch for Pump (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22XPMA-I2W-120V)
Red Illuminated Selector Switch for Element (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=PBC-SS22XPMA-I2R-120V)
Contactor, 2 pole, 30A, 120V Coil (http://www.pioneerbreaker.com/ProductDetails.asp?ProductCode=CN-PBC302-120V)
5-circuit Terminal Block 30A (http://www.mcmaster.com/#7527K85/)
3-circuit Terminal Block 30A x3 (http://www.mcmaster.com/#7527K83/)
Terminal Block Jumpers (Pack of 25) (http://www.mcmaster.com/#7527K99/)
1/4" Diameter Glass-Tube Fuse 3AG, Fast Acting, 250 VAC, 7 Amp (http://www.mcmaster.com/#7085K45/)
1/4" Diameter Glass-Tube Fuse 3AG, Fast Acting, 250 VAC, 1/2 Amp (http://www.mcmaster.com/#7085K42/)
1/4" Diameter Glass-Tube Fuse 3AG, Fast Acting, 250 VAC, 3 Amp (http://www.mcmaster.com/#7085K39/)
1/4" Diameter Glass-Tube Fuse 3AG, Time Delay, 250 VAC, 2 Amp (http://www.mcmaster.com/#7085K89/)
Fuse Block for 1/4" Diameter X 1-1/4" L Fuse 2 Poles x2 (http://www.mcmaster.com/#7687K14/)

brewery control panel design.png
 
It looks fine, although two things you may want to consider:

E-Stop button, a simple circuit would be a a NO pushbutton that connects a small fuse and resistor to ground causing the GFCI to trip (assuming you have gfci :))

You also may want a contactor in between the element and switch, I dont think you want 23A running through that switch...
 
It looks fine, although two things you may want to consider:

E-Stop button, a simple circuit would be a a NO pushbutton that connects a small fuse and resistor to ground causing the GFCI to trip (assuming you have gfci :))

You also may want a contactor in between the element and switch, I dont think you want 23A running through that switch...

Good call on the element switch. I missed that one. I've updated the schematic. I split the 2-pole contactor into 2 1-poles, each controlling a hot leg. The first contactor controls the SSR/Pump Leg and it switched on/off by the main power switch, the second contactor gets it's supply before the main power switch, but the coil is in series with both the main power and element switches. I also moved my 1A fuse further back to protect all of the control logic. Is 1A sufficient for the draw of 3 Illuminated switches, alarm buzzer, 2 contactors, SSR and PID? Also, is it necessary to isolate Neutral with a contactor, or is it safe to leave it connected?

As to the E-stop button, I think my first instinct in the event of something horrible would be to yank the power cord, not go for a button on the control panel. And I can see myself bumping it and shutting everything down by mistake. I think I'm going to leave it out. I definitely have GFCI though. I've got one of those 30A copy machine cables in my parts list. Thanks for the input!
 
Your alarms connections are not wired up right. The alarm connections are switches and not power outlets.

The one you have labeled as "AL-N" should be connected to the same thing as your "AC-HOT". When an alarm triggers, AL-N will be connected to AL-1 or AL-2, depending on which alarm fired. This will send 120V to your buzzer and then the buzzer needs a connection to neutral to complete the circuit.

A better way to think of the alarm pins as you are using then is:

AL-N is really an "alarm power in" pin
AL-2 and AL-1 are two "alarm power out" pins

Like this:
alarms.jpg
 
Is 1A sufficient for the draw of 3 Illuminated switches, alarm buzzer, 2 contactors, SSR and PID?

It depends on your contactors. The ones I use pull 0.5A each. If yours is like mine, then the two contactors alone are likely to blow your fuse.

Also, is it necessary to isolate Neutral with a contactor, or is it safe to leave it connected?

It's not necessary to switch the neutral. In fact, it's generally suggested to specifically NOT switch the neutral.


One thing I don't like about this design is that the only way for you to 100% kill the voltage to your element is to shut the whole system down. Your "element" contactor will ensure that there is no heating, but it only shuts off one of the hot lines going to the element,. The other hot line (the one that feeds through the "system power" contactor) can still be live even when your "element" switch is OFF.
 
I also noticed that your parts list only contains a single 2-pole contactor, but your schematic contains two separate single-pole contactors.
 
Your alarms connections are not wired up right.

Thanks for that. There wasn't a very clear explanation of the wiring for the alarms in the Auber documentation. That makes much more sense.

Walker said:
One thing I don't like about this design is that the only way for you to 100% kill the voltage to your element is to shut the whole system down. Your "element" contactor will ensure that there is no heating, but it only shuts off one of the hot lines going to the element,. The other hot line (the one that feeds through the "system power" contactor) can still be live even when your "element" switch is OFF.

I was thinking that the PID/SSR would act as the shutoff for that second leg, but I see your point. If the element switch is off, it really ought to be completely off. Any reason I can't wire things up like this?

control panel schematic b.png


None of the 120v electronics are particularly power hungry, so it should be fine to run them directly off of the switch, right? And I've got a fuse to further protect things should they go awry.

Walker said:
I also noticed that your parts list only contains a single 2-pole contactor, but your schematic contains two separate single-pole contactors.

The schematic and parts list just got a bit out of sync. I'll update the list when I get the schematic more finalized.

Thanks again for all the input! Much better to hash things out now than once I've already purchased everything...
 
That seems fine. The [System Power] switch turns on the PID and passes power through to all of the secondary switches to individually turn on the other items.

Personally, I'd suggest putting in a secondary fuse to protect the PID better than it is in the diagram. The PID requires less than 0.5A. Fuses are cheap insurance for expensive components. My system uses something like a 0.333A fuse to protect my PID and a 2A slow-blow fuse to protect the pump.
 
Alright, cleaned up the schematic above and added some fuses for protection of various components. Unless anyone has further suggestions or critique, I'm going to start ordering components!
 
That E Stop idea I think was PJ's. Pretty simple and I had the same concerns about bumping into it, but I put it in anyway. If you are being lit up by 30a/240 and that yellow button is nearby, it's a heck of a lot easier to hit that then pulling out a plug. If it is just some equipment malfunction then pulling the plug is ok. In my case the plug is in a different room so couldn't do that anyway.
 
That E Stop idea I think was PJ's. Pretty simple and I had the same concerns about bumping into it, but I put it in anyway. If you are being lit up by 30a/240 and that yellow button is nearby, it's a heck of a lot easier to hit that then pulling out a plug. If it is just some equipment malfunction then pulling the plug is ok. In my case the plug is in a different room so couldn't do that anyway.

Correct me if I'm wrong, but if current is running through you instead of its intended path, that's going to trip the GFI way faster than you could ever hit an E-Stop button. And that's assuming that you could actually do anything at all with 30A/240V running though you (which I think is unlikely)...
 
Correct me if I'm wrong, but if current is running through you instead of its intended path, that's going to trip the GFI way faster than you could ever hit an E-Stop button. And that's assuming that you could actually do anything at all with 30A/240V running though you (which I think is unlikely)...
You are correct. It'll trip if you get hit with the power.

However, it is an Emergency Stop. It is designed for an emergency kill of the system. You decide (as you already have) if it's worth it. Anyhow, I can think of a few events that actually prompted me to design the circuit in the first place.
 
:off:

Any personal experiences of getting shocked with 240v 30A?

How badly does it hurt? for how long?
 
Anyhow, I can think of a few events that actually prompted me to design the circuit in the first place.

Curious to know what sort of circumstances you find it necessary. I'm not beyond convincing, but nobody has presented a circumstance where it's actually useful to build this in.
 
:off:

Any personal experiences of getting shocked with 240v 30A?

How badly does it hurt? for how long?

no personal experience here, but depending on how good of a contact you make with that voltage, it may not hurt for very long.
 
Curious to know what sort of circumstances you find it necessary. I'm not beyond convincing, but nobody has presented a circumstance where it's actually useful to build this in.

How bout if your being electrocuted and swmbo walks into the garage. You cant press the button because your being shocked.. but she sure as heck can
 
How bout if your being electrocuted and swmbo walks into the garage. You cant press the button because your being shocked.. but she sure as heck can

I don't mean to sound cantankerous, but this circuit does not do any good in the case of electrocution. The GFI will trip within milliseconds of such an event. And, assuming the GFI had somehow failed, the circuit would not function as expected anyway, since it relies on the GFI to break the circuit.
 
I don't mean to sound cantankerous
...
Hey. Just drop it and do it your way. It does not matter to me in any way shape or form. At this point there is not one thing that anyone can say to enlighten you.

So - after all - It's your rig, your build & your way. Just do it and quit the belligerent arguments.

Thank you.
 
Here you go... two scenarios where I want an e-stop.

1) a hose ruptures and starts spraying wort all over. Press e-stop.

2) I start to smell that tangy electrical fire smell while brewing. Press e-stop.
 
Here you go... two scenarios where I want an e-stop.

1) a hose ruptures and starts spraying wort all over. Press e-stop.

2) I start to smell that tangy electrical fire smell while brewing. Press e-stop.
Excellent.!
There are many more examples.!

I have a few more & that is the reason why I designed my simple circuit for an E-Stop.

Just a word of caution. Do not underestimate the power of an electric circuit and what it can do to you. I have a personal experience with it that will boggle your mind. I'm lucky to be old and alive today.!!! I'm talking about an incident 50 years ago.!
 
After thinking about it over the course of the day and a bit of out of thread discussion with P-J, I realize that I'm being a bit silly asking for examples for when an emergency item is necessary. Of course it's not necessary until there's an instance that was unforeseen. Better to have it there in case you need it than to need it and not have it. I'll incorporate the circuit into my schematic. Hopefully I can manage this bit without screwing it up!
 
Alright, finally found time to update my schematic. I've appropriated the safe start interlock design from Kal's build and put a momentary NC mushroom pushbutton inline with the relay's coil. A slap of that button should shut the whole system down, requiring that the pump and element switches are turned to the off position before it will power back up. Also, here's a link to my current parts list (this is for my entire project, the relevant parts are mostly down at the bottom in the "Control Panel" section):

https://spreadsheets.google.com/spr...OHAxU2hIVGdOLUE&single=true&gid=4&output=html

And the updated schematic:
control panel schematic final.png
 
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