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Hello,
I plan to design a simple PLC with the PIC.
I wonder if anyone has an idea for a user interface, and how to realize the logic in the PIC?
PC application will be made in Visual Basic. I probably will use serial communication for settings...
PLC would be to have two analog inputs (4-20 mA), 4 or 5 digital inputs and 4 or 5 digital outputs.
For digital inputs and outputs i'll use optocouplers, for analog inputs HCPL788J.
I have been working on that concept for a while. Think it takes a little system designing such as, timed interrupt loops as a base timing frame-work, serial recieve and send to/from PC for data and instructions, (needs to be rt interrupt) since pic can't just wait around, and some type of simple protocol for sending and recieving different data ?
scratching my head,
don
amgen
This may help you. Always interesting to see what others have done. Not in picbasic, (but it is compatible with PICs) but might give you some ideas. http://cq.cx/ladder.pl
I used to be able to find a PLC made out of a PIC that was a commercial product, with screw terminals and a din-rail case, but I can't seem to find it anymore. If I remember right, this company also produced a ladder logic compiler. The PLC was about $200.
Could it be this The Low Cost Tiny Ladder Logic PLC ?
Almost! Whew, I thought I was having a senior moment. It was the MIAC, made by the company that does FlowCode.
http://www.matrixmultimedia.com/miac.php
http://www.youtube.com/watch?v=NHnWzVoJJN0
It uses a PIC18F4455
Here is one open sourced version
http://www.pudn.com/downloads65/sour...ail232973.html
And another
http://cq.cx/ladder.pl
Thanks... There are good ideas.
I forgot to say that I would put the counter on each input, and several timers.
Ladder is too complicated to be quickly and efficiently done in vb6.
I think I found a good example of what I wanted to do.
These are the moxa controllers with Click & Go logic.
I'll probably use a GPRS connection for monitoring...