PLC 101

Even though I haven’t shown it here yet, I’m a coaster enthusiast. The interest really grew in 2003, the year this thing opened:
vlcsnap-2012-10-22-16h46m20s177

Sledgehammer at Canada’s Wonderland was a new ride from HUSS Rides of Germany. It’s still the only Jump Squared in the world, and is still going 10 years later. As an obsessive enthusiast of the park, I read the press release for it over and over. I remember it describing its control system as the “most sophisticated computer in the park”. Ending up on the HUSS Rides website, I picked up the acronym “PLC”, Programmable Logic Controller. Fast forward 9 years, I had opportunities to learn a little more about them.

In May 2012, I took the George Brown College Programmable Logic Controllers program. Having learned other programming languages, it wasn’t too hard to pick up compared to what a fresh programmer may feel. After that summer, I had a couple PLC courses in my Seneca College program, though it wasn’t nearly as detailed as what I learned that summer. And even with all of this training, there is still a lot for me to learn. I think I have a good basic foundation, though I definitely need to challenge myself when I practice.

Anyways, finishing the George Brown program early in the summer, I decided to work on my own PLC trainer for the rest of the summer. There were pre-built trainers for sale, but I challenged myself to build one for the experience and to see if I could beat the price. They varied in price and features, most of them at least a couple hundred dollars. Long story short, I went over budget by $100, with a grand total of $300…

I learned how to use a really old version of Autosketch back in high school. It’s what I used to design the layout of the panel to get it drilled and built:

sketch

The next part is a little embarrassing. I bought all of the components from Automation Direct. Once I received them, the next part was wiring it up. I was used to wiring the Arduino, expecting power to flow through the pin to ground. Why weren’t my lights working? Because I didn’t know what I was doing.

After some reading up, I realized what I was doing wrong, so I corrected it. On to problem #2: Broken Output. This is what a failed lamp test looks like:

lamptestbroke

I purchased another CPU (the Click PLC CPUs have some I/O pins on it). That set me back $70. I also had to buy some more wire because:

20120629_151054So that about ends the story for the first generation of my PLC trainer. There’s still some more work I did on it to show off. I also picked up a few more parts today to do a minor upgrade. Fair warning: I still probably don’t know what I’m doing. Thanks for reading.

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