Raspberry Pi Control Box
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I don't see any mechanical switches. Solid state relays do not remove voltage from the element outlets. They only restrict max current to a few milliamps. SSR's can also fail in the on mode, in which case having a contactor in series with the SSR gives you a way to galvanticly isolate the incoming power from the element outlets.
Something else to think about: what are your SSR's going to be doing while the RPi is booting up?
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Something else to think about: what are your SSR's going to be doing while the RPi is booting up?
Brew on
(first.. sorry, I know its a mess. I hope its at least a little followable) ok, so now.. the power comes directly into a relay and the coil is actuated by a key switch. then I put a relay in for each 240v element, and switched the coils independently so I can turn the off manually if I wanted. I would also probably switch each side of the 110v outlet independently as well.
I am not understanding your question though as to what the SSR will be doing when the RPI is booting up. I'm guessing your saying that the PI will send voltage to the GPIO header? I wouldn't think they would, but I'm not an expert. i guess, as long as the manual switches are off for the elements then nothing would happen.
I am not understanding your question though as to what the SSR will be doing when the RPI is booting up. I'm guessing your saying that the PI will send voltage to the GPIO header? I wouldn't think they would, but I'm not an expert. i guess, as long as the manual switches are off for the elements then nothing would happen.
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craigmw
Well-Known Member
I strongly suggest adding fuses to the 110V (120V?) sockets. Without fuses, those wires could potentially attempt to carry a load of the breaker (50A?) connected to the power in on the box. A short or overload on the 110V line would very likely melt the 110V and possibly cause a fire. You can purchase in-line fuse holders with 10A (or so) fuses in them, though I think the panel mount fuse holders from Buss are a better and safer bet.
good call.. ill implement that as well
Second version looks much better.
You can leave out the "main power" relay, and just connect the output of the key switch to the 12V power supply, the 120V outlets, and in series with the element relay/contactor control switches. This only works if you expect a total 120V load of less than 10A. A typical Chugger pump draws about 1.4A.
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You can leave out the "main power" relay, and just connect the output of the key switch to the 12V power supply, the 120V outlets, and in series with the element relay/contactor control switches. This only works if you expect a total 120V load of less than 10A. A typical Chugger pump draws about 1.4A.
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craigmw
Well-Known Member
Indicator LED lamps wired between the two "hots" after the relays/contactors feeding the 240V elements are also suggested. This way, you will know when the elements are active and could help to prevent dry firing and other mishaps.
craigmw
Well-Known Member
You might want to move the element indicators to after the relays and SSRs to show they are active only when the relays are on. Otherwise, this is looking very nice. Also, the fan may be unnecessary if you use the proper heat sink. I purchased an Auber panel with an associated heat sink and on my panel, I've never noticed the heatsink getting beyond warm. It's one less item to worry about and then you could just use a USB 5V power supply to power the RPi. My panel is only a single element/30A panel, but they sell panels with heatsinks rated for 50A/240V as well.
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craigmw
Well-Known Member
You will want to run your indicator lamps in parallel with the output sockets rather than in series. So, for the 240V outlets for the heating elements, connect each LED indicator to the black and red wires that lead to each socket. For the 120V outlets, connect the LED to the black hot wire and the neutral bus. If you wire it as pictured, you will quickly fry your indicator bulbs when a load is connected.
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like this?
Here is the Amazon pick list.
Amazon.com - Idea Lists
Amazon.com - Idea Lists
craigmw
Well-Known Member
This looks good. Just make sure that your red and black wires between the relay/contactor and 240V outlet connects to the led indicator in parallel. One way to do so is to connect wires from the outlet side of the contactor directly to the LED. Most 240V contactors have multiple connectors for each output pole. You also might put the 120V LEDs on the other side of the fuse so that the failure to see an indicator when switched on would tell you that a fuse was blown.
craigmw
Well-Known Member
I'd suggest getting an Auber box. They are really nicely designed and will make building this much easier than a PVC box as listed. This one looks like it might work:
https://www.auberins.com/index.php?main_page=product_info&cPath=34&products_id=384
Order this with the 60A or 72A heat sink so you can mount two 40A SSRs (assuming load less that 60 or 72A total load, respectively)
Ideally the fuses are placed where the wire size drops from the incoming power source. If you place a single 10A fuse on the unswitched side of the main power switch, you are covered.
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Ok. Good to knowIdeally the fuses are placed where the wire size drops from the incoming power source. If you place a single 10A fuse on the unswitched side of the main power switch, you are covered.
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The way you have wired the "element firing" lights, they will come on when the RPi is telling the SSR's to send power to the elements even if the switches controlling the element contactors are off. And, there is a good chance that due to the off state leakage current of the SSR's, that they will be on all the time (although brightness may vary.) Those lamps should be moved to the switched side of the element relays/contactors.
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hmm.. i had that configuration above (picture with the amber LED's and was suggested to move to other side of relay in order to tell if the contact was actually closed and firing the element. i guess you could still have power across the coil and the contactor be shorted open and the lamp would be on but no power to the element. What's the best side to error on?The way you have wired the "element firing" lights, they will come on when the RPi is telling the SSR's to send power to the elements even if the switches controlling the element contactors are off. And, there is a good chance that due to the off state leakage current of the SSR's, that they will be on all the time (although brightness may vary.) Those lamps should be moved to the switched side of the element relays/contactors.
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joelbear5
Member
I built something similar. The element rocker switches control the 3.3V DC signal from the RPI (which I have custom NodeJS web server with PID running on the Raspberry Pi).
I don't have any fuses, but it is attached to a GFCI 60A breaker. Maybe I should add fuses. I ran the 120V line to the contactor through both the key switch and the main power switch on the front power - but I think hindsight that it's overkill.
Mistakes:
- Original SSRs would NOT TURN OFF after they got hot! Very scary on the kettle getting a boil-over. I eventually found ones that I haven't had any trouble. https://www.amazon.com/gp/product/B00E1LC1VK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 I recommend a pull-down resistor ~10K for each 3.3V DC signal from the RPi.
- I put the 30A 240V plugs too close together. The large diameter plug on the cord interfered and I had to re-drill the hole location.
- OneWire temperature sensors (DS18B20) needed a real-time clock, so I had to make custom ATTiny85 microcontrollers with I2C communicating back to the RPi (calculate pull-up resistors as the ATTiny85 has too-high resistance build-in pull-up resistor).
- Attaching btween 1-3 OneWire temp sensors required lower pull-up resistor or I got erroneous readings. I think I settled around 2K instead of 4.7K. I don't recommend using OneWire temperature sensors for the only benefit that you can plug any temp sensor into any RJ45 connector.
- I connected a 7ft 6/3 power cord to my box. Very annoying to move the box around with a 10lb cord attached. I recommend putting a 240V 50A plug on the box itself.
- Use 3.5mm Audio cables/connectors for the temperature sensors at both ends - I try to walk off with a hot/heavy mashtun and only to realize it's still attached (RJ45s do not pull out!)
- I use 5500 watt ULWD elements. For a 14 gallon batch a 50-60% duty on 240V will keep a rolling boil indoors. I hard-coded a separate boil power setting when kettle temp is over 205°F to prevent boil-overs. Defaults to 50% and does not use PID over 205°F, but is configurable via my web interface touchscreen.
- Get a screw terminal hat for the RPi - super convenient!
- I used a dual port USB power for the dual fans (one in, one out) and the RPi. The 1/4" female spade crimp connectors fit over the 120V prongs very nicely.
- As mentioned in previous comments, the SSRs need the two terminals shorted (as in with elements) because they bleed a small amount of voltage and will dimly light your signal lamp when the power cords are not connected to the elements. I don't mind it as it's super dim and not confusing with "ON". Also tells me that the 30A 240V cords are not plugged into the kettles.
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joelbear5
Member
After studying your latest drawing update a bit more, it looks great! Adding the relay after the SSR is a great improvement. If you have auxiliary 120V available, such as a power strip on your brew bench, I wouldn't even bother adding it to your box. Then you could even get away with 6/2 wire since the neutral isn't necessary for anything. USB "wall warts" will take 240V just fine. FWIW, I have my two pumps mounted under my bench to a dual light switch box instead of taking room up in my control box.
-Joel
-Joel
hmm, that does pose a situation now doesn't it.. what is the current Raspberry PI solution for brew controller then?
The same hardware will work with many projects, which is a benefit of using an RPi.
CBPi still works as it is, so you can still use it. You might run into some minor bugs or disgruntled users, but it's fine.
If you want something actively developed you could use Node-Red (see Facebook Groups). Pretty popular for home automation/hobby process control, and has a large user and developer base (see Node-RED Forum). Customizable to the point that it's inaccessible to some, but I would say that it's learnable by anyone. It's not programming so much as stringing predefined functions together (e.g. trigger a temperature reading, do a moving average of that temperature reading, then display it as 3 separate functions/nodes wired together in a sequence. Or take the temperature reading and feed it into a PID algorithm in the same way.)
brewblox (Brewblox) looks really nice, but would require another module to use with it.
May be look to those
https://dev.azure.com/garageinnovation/_git/BrewCtrl?path=/BrewCtrl or BernhardSchlegel/BierBot
https://dev.azure.com/garageinnovation/_git/BrewCtrl?path=/BrewCtrl or BernhardSchlegel/BierBot
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augiedoggy
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You might want to look into Brucontrol as well if you havent already just as another option that might fit the bill better for growth and support down the road....
Its arduino based and not free but it has a huge amount of people including myself using it. and its reliable, enough so that I use it to control my 3bbl brewhouse at my brewpub and have been for 2 years now. It also has tons of flexibility with being able to control multiple controls and control panels on the same network. I use it to control my chiller and fermenters as well as my show tilt info. it also works with any type of temp probe hardware and multiple relay boards which is nice
I use rasberry pi s for my beer list displays and even with that duty Ive had the SD cards crash twice and need reformatting and one pi unit fail and need a full replacement in the last 2 years.
Its arduino based and not free but it has a huge amount of people including myself using it. and its reliable, enough so that I use it to control my 3bbl brewhouse at my brewpub and have been for 2 years now. It also has tons of flexibility with being able to control multiple controls and control panels on the same network. I use it to control my chiller and fermenters as well as my show tilt info. it also works with any type of temp probe hardware and multiple relay boards which is nice
I use rasberry pi s for my beer list displays and even with that duty Ive had the SD cards crash twice and need reformatting and one pi unit fail and need a full replacement in the last 2 years.
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StrongArmBrewing
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augiedoggy
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Some things never change. You know when I made my last post with my recommendation based on what I use I figured you would chime in again with your incorrect assumptions that I have some affiliation with Brucontrol. Why is it ok for you to make recommendations based on what you have experience with but when I do the same you accuse me of advertising? I mentioned it because he might not be aware it exists or how it works and it always helps to be aware of your options before starting down any path. arduino setups are very similiar to the raspberry pi setups so its worth mentioning, especially when the OP just learned that CBPi is a discontinued piece of software. I have no motivations here other than sharing my experiences with the different setups Ive built and used.
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Hi guys,
I realize that a commercial solution will draw ire when proposed in a freeware thread. I respect that and avoid providing advice on such threads when someone asks for potential solutions. I sincerely appreciate @augiedoggy's endorsement, and I'll affirm that he is not formally affiliated with BruControl. He is a user who I think has had a good experience - hopefully because we provided technical support for his build and help ensure his success.
That said, since you called him out for an inappropriate recommendation @golfindia, I will do likewise and state your continual highlight of a plastic toolbox as an acceptable enclosure for a high voltage/current control system is misguided. Many homebrewers stray from electrical codes or industrial standards due to funds, knowledge, and time, and that is understandable. However, actively demonstrating a dangerous design (flimsy, hole in top, fire hazard, etc.) which others may look to emulate may put them in harm's way should they follow your path as an experienced builder. Homebrewing is awesome that people are always willing to share and help out - but we need to be mindful of the risks that someone could get hurt with unsafe advice.
I realize that a commercial solution will draw ire when proposed in a freeware thread. I respect that and avoid providing advice on such threads when someone asks for potential solutions. I sincerely appreciate @augiedoggy's endorsement, and I'll affirm that he is not formally affiliated with BruControl. He is a user who I think has had a good experience - hopefully because we provided technical support for his build and help ensure his success.
That said, since you called him out for an inappropriate recommendation @golfindia, I will do likewise and state your continual highlight of a plastic toolbox as an acceptable enclosure for a high voltage/current control system is misguided. Many homebrewers stray from electrical codes or industrial standards due to funds, knowledge, and time, and that is understandable. However, actively demonstrating a dangerous design (flimsy, hole in top, fire hazard, etc.) which others may look to emulate may put them in harm's way should they follow your path as an experienced builder. Homebrewing is awesome that people are always willing to share and help out - but we need to be mindful of the risks that someone could get hurt with unsafe advice.
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That looks amazing! I love that RPi touchscreen, what is the software that you are using for it?
craigmw
Well-Known Member
I like this implementation because it incorporates design features of industrial control panels with a GUI front end. I built my 1V/240 volt panel around a DSPR320, but at some point would like to upgrade it to RPi control. In my case, I'll probably adapt my CellarWarden software to allow for control of the brewing process. It also uses a Node.js-based server that links to a javascript front end, so it could be presented on a touchscreen on the front of the panel (or controlled remotely via any browser). I just need to find some time
I appreciate the alternative points of view, and feel that all commentary is beneficial. i also dislike when people get their panties in a twist and start calling people out. if it isn't what they are looking for they just need to hold their tongues.
currently finalizing construction of the brew space, and will then start putting the kettles, pumps, steam hood in place, and will then concentrate on the electronics. ill post pictures soon
so I realized the power cord I am using is not 4 wire, its three wire L5 plug(stupid oversight). To your point then, I am going to have to take the 120v accessory circuit out of the box. I do have 120 on the wall already, so i can plug the pump into that. The problem i see now is that my relays require a neutral to switch the 120v coil. Should i pull the wire from the circuit panel and replace with a 4 wire L14 plug? or should i rework my control box to include 240v switched relays?
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Just to touch on one thing of your wiring. If I see it right your pumps are both pulling power off of the same buss bar in your panel... its almost not even worth mentioning in this small scale but its best practice to balance your loads across both sides of your incoming 220 both going back to neutral but both pulling from a different leg of power!
This is such an issue in my eyes. i was a CBPI user for three years. and just made the switch to BrewBlox With Brewpi.com... The community is amazing an issues that you have or find with the software will be fixed and updated within a few weeks sometimes even hours if it is a bad enough bug, but that's so rare...
Brewblox is lightyears ahead of everything that is out there in my eyes for the average homebrewer. Just the ability to automatically control the temp of your grain bed by itself, by using a pid to drive another pid in eiter your herms,rims, or kettle in BIAB... and the ability to automatically balance two elements on one 30amp circuit!!! I run both my kettle and rims tube at the exact same time and it balances the load and never fires either at the same time, just switches fast maintaining what ever % of duty that it needs to do its job that you are asking of it!!!
like above said. best to keep this to the point. but i would hate to see you go doen the CBPI road and then have to rewire. dont waste your time. its a dea project and the community is drifting!!
This is such an issue in my eyes. i was a CBPI user for three years. and just made the switch to BrewBlox With Brewpi.com... The community is amazing an issues that you have or find with the software will be fixed and updated within a few weeks sometimes even hours if it is a bad enough bug, but that's so rare...
Brewblox is lightyears ahead of everything that is out there in my eyes for the average homebrewer. Just the ability to automatically control the temp of your grain bed by itself, by using a pid to drive another pid in eiter your herms,rims, or kettle in BIAB... and the ability to automatically balance two elements on one 30amp circuit!!! I run both my kettle and rims tube at the exact same time and it balances the load and never fires either at the same time, just switches fast maintaining what ever % of duty that it needs to do its job that you are asking of it!!!
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There are some reasons in small panels where it makes sense to run both pumps from the same hot leg:
- You can protect the wiring for two pumps with a single 10A fuse, and use 16AWG wire for the pump circuits
- If you use an ammeter to measure the total current draw in your panel (not just the element), this becomes way more complex if you don't power all the 120V loads from the same hot leg
