- Apr 23, 2000
- 631
- 4
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I am working on an industrial control application, and originally we were going to just use a microcontroller (a 16-bit PIC) but the more we think about it, the more we think a PLC might be the answer. The task is simple: an encoder will likely tick in the 50-100us range, and we need to turn a digital output on every 10ms of ticks or so. We may need a few other operations to happen in parallel, but nothing too complex. Certainly not taxing a PIC by any means.
However, it is an industrial environment and needs to run 24/7/365 for a few years in a somewhat harsh environment, and I know PLCs are qualified for such demanding tasks. This is my first time looking at them, and I want to cry... ladder logic hurts my coding soul. I am looking at the "scan rate" and they seem to execute loops in the ms range, and I am not sure that this will be fast enough. I normally code PICs to be all interrupt driven, and I am not sure I will have enough control/speed over the interrupts on the PLC. Does anyone have experience with them? Are my speed requirements too much for a PLC? Also, I cannot believe you have to pay for the RSLogix software package to program these things...
However, it is an industrial environment and needs to run 24/7/365 for a few years in a somewhat harsh environment, and I know PLCs are qualified for such demanding tasks. This is my first time looking at them, and I want to cry... ladder logic hurts my coding soul. I am looking at the "scan rate" and they seem to execute loops in the ms range, and I am not sure that this will be fast enough. I normally code PICs to be all interrupt driven, and I am not sure I will have enough control/speed over the interrupts on the PLC. Does anyone have experience with them? Are my speed requirements too much for a PLC? Also, I cannot believe you have to pay for the RSLogix software package to program these things...