PLCReturn to CodeReturn to Portfolio While in the last few months of my Robotics course, I took on a challenging task - programming a PLC for Seattle Opera's World Premier of Wagner's "The Ring of the Nibelung." When I told my instructor, his comment was "now the real learning begins". How true. The PLC controlled motors in two separate 16,000 lbs., double sided scenic elements, which had to move in a choreographed motion during a scene change for the opera. What I found to be the biggest programming challenge was to be able to, in rehearsals, start, stop, back-up, and re-start the action in any given part of the motion. The actual move for the show was simpler - push the button and let it go. The other big challenge, perhaps even bigger, was because of the physical size of the scenery, there was no chance to run it completely or debug the program before we set it up onstage. I had proven components of the program in the shop, but not the whole thing, and I had about four hours to make it work before the first rehearsals. It worked, not as well as I had hoped. But it worked. Here are links to a code excerpt from that PLC program, some documentation and memos about the project. As with all of the projects I build, repair and maintenance are an important aspect of the job. To help with that, even if I'm the guy doing it, is documentation and code comments. I've already experienced the "what was he thinking here" with my own code, I wouldn't want to do that to someone else.
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