Brew Controller: Finishing touches

I got the panel completely wired and partially tested. I had to figure a way to turn on the SSRs for the pumps without using the SSR output (Can’t write to the modbus register while in operational mode). I decided to just run through one of the alarm relays and run that way. It works great and turns on my drill, lights, etc without issue. Didn’t want to test with dry pumps.

I spent some of last Sunday getting the finished panel mounted to my brew cart. Just had to adjust the shelves and create a mounting plate and bolt right up. I still need to mount the pumps. Also mounted my Touchscreen computer to the wall close to an outlet. I didn’t want it on the cart itself, but in the shade just inside the garage. I realized the power supply also has a 2.5A USB power port on it, so that’s handy.

The new twistlock plugs were wired to the heating elements I had. They were hardwired to a dryer plug before when I was doing extract brews, so just needed to wire in the new cable and plug. I haven’t tested them yet, as I finished late, but it’s close. The temperature sensors still need thermal compound put inside them, but are otherwise working and measuring temperature.

Also embedded a nice little countdown timer (preset for 1 hour, but changable). Its just an embedded website, so I’ll likely update it later. It works for now though.

So all that is left is mounting the pumps and filling the HLT and BK with water and running the autotune on the PID’s.

Here’s some recent pictures:

Brew Controller: Panel Wiring

Another little update. I’ve been working on the interface some more, as well as getting the panel wired up. I still need to get the low voltage stuff wired to the PID controllers, get the modbus wired and install the wifi dongle/antenna cable.

I’m using some of the unused outputs (alarm ouputs) on the PID controllers to drive the SSR’s for the two pumps. I’ve also wired the E-Stop to the coils on the two 2-pole contactors for the heating elements in case I need to shut down. This will let me keep control power live.

The PID’s have a nice feature on them where you wire in a Current Transformer. This will let you see how much current is going through each SSR. This allows me to ensure that I can tell if a heating element is open circuit if the SSR is on and I see no current, or that the SSR is shorted if the SSR is commanded off and I see current.

Also, since then, I got a medical grade Touchscreen computer and a mounting arm off eBay. This will be my new interface for the brew panel, and will also allow me to check on the temp chambers. Here’s a video of the interfaces of both:

Here’s some pictures of the LCD touchscreen computer:

And some pictures of the panel:

Brew Controller: Assembly

I made some more progress on my electric brew control panel this past weekend. I got everything mounted and ready for wiring. Just some small tweaks and a few more parts and I can mount it to the wall and take it for a spin and brew some beer.

This week I’ve been working some on the HMI that I’ll be running on the Raspberry Pi. I’m not changing a ton of the layout, just getting more of the Modbus Registers added and configured. I’m going to use the spare outputs on the PID controllers to drive the SSRs for the pump motors. These Eurotherm PIDs have a Current transformer input that can monitor the current going through the heating elements. This will help show if the SSR is shorted and also I can guesstimate instantaneous power.


Brew Controller: Update

This last year has been busy. I married my longtime girlfriend and we bought a house together. As with all things home-owner, there are projects, so my home-brewing has taken a back-seat while we made some improvements. We had some plumbing redone that required us to do a little remodeling in our bathroom. That is nearing completion and I’ve started focusing back on my brew controller.

I got the Receptacles and inlets all mounted and screwed down, but I’ve had difficulty in fitting everything I want into my controller. The Watlow MicroDIN PID controllers I originally got are pretty large, and so is the power meter. The rest is pretty small and fits easily. I don’t want things on top of each-other and wires running everywhere like a rats nest. I started looking at some options for alternate PID controllers and found some Eurotherm PID controllers for $22 or best offer on Ebay. I made the guy an offer on 8 (4 for this and 4 extra for other projects). They’re about half the width of my Watlow MicroDIN controllers.

The great thing about these, is that I can bypass the controller and toggle on and off the 3 alarm outputs, which allows me to turn on and off my pump SSRs. Another cool thing, is that they have a bus that connects all of the power and communication. The really handy part, is they have an input for a current sensor. This allows me to look at the current while the SSR for the boil coil is on, and alarm if it gets out of range (shorted coil, or open circuit), and when the SSR is off, it will detect leakage current, which means a failed SSR. I can read the value and at least tell roughly how much current is flowing.

I also worked more on the HMI and think this version is fairly clean and gives me most of what I’ll need to see while brewing. There’s an Aux temperature readout, but I haven’t figured where I want that to be.

I also need to do some electrical work in our garage. Since we moved, I no longer have a 30A 240V receptacle. Since I’m going to have 2 fermentation chambers and my brewing equipment possibly running at the same time, I’m going to run a 50-60A service over across the garage from my main panel to a panel that is meant for temporary power for RV’s. It has a 50A GFCI/50A outlet and 20A breaker/GFCI duplex. I’ve ordered it and should be able to install in the next few weeks, and finish my control panel.

Brew Controller

With the jump to All-Grain brewing with an electric HERMS system, I need some way to control it. I’m a controls engineer and work with a ton of Modbus devices for work and decided that I’d like to control/monitor over Modbus. This eliminates a lot of the buttons/switches/indicators, etc. I’d seen some people using PLC’s on the forum and started talking to one of them (Brad) from HomeBrewTalk, who has been awesome.

The main part of electric brewing, is that you need something to control the elements. Most people use PID controllers, or a PLC running PID control loops. In talking to Brad about his advice, he mentioned he had 4 DIN-rail mounted PID controllers. No display, just Modbus RTU control. They’re Watlow MicroDIN controllers and do everything I need and work with RTD or Thermocouple inputs and dr4ive SSRs directly. I bought them from him and started building the panel.

As a means to talk to these, I use an Ethernet gateway from the company I work with, an Obvius Acquisuite. It translates Modbus TCP (Ethernet) to Modbus RTU (RS485). I also started researching ways to visualize the data using some sort of HMI software. After evaluating many solutions, I stumbled across MyScada. It can run on a computer, on an android device, or as a webserver on a Raspberry Pi. I chose to run on the Pi, so I can use any web-enabled device on my network to access the control screens.

So far, the panel will house the 4 controllers, The gateway, the Raspberry Pi, 4 SSRs, a main contactor, E-stop, Keyswitch, fuses and power supplies. An Android tablet will serve as the interface.

I got the PID controllers a couple weeks back and got them working and talking to the MyScada software. It’s really easy to design clean HMI screens. The free version is limited, so I went ahead and bought the license (very reasonable prices). It does full alarming, it logs data (useful for recipe re-creation), can SMS, email on alarm, has user levels and can graph trends/history.

I experimented with a few screens and the first one below is the latest iteration as of today. Also below are some pictures of the panel: