I have a T100MD888 PLC and with a Motorola 68HC12 microprocessor connected to it through the RS232 connection.
I would like to recieve an 8 bit value from the microprocessor but after looking at the help file I don't think this PLC has the capabilites to do it.
Therefore I would like to set the PLC up to recieve an ASCII character just to demonstaete that communication is possible, this is for the final part of my uni degree project as I have to prove that the PLC will read information from the microcontroller.
I've asked this question before and this was the answer you gave me:
You can use the ?
A$ = INPUT$(1) ?
command to receive ASCII string inputs that are terminated with CR (ASCII 13, carriage return). This function returns an empty string if there isn't a completed string in the buffer. You need to execute this command periodically until you don't see a empty string.
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I tried this but nothing happens. I'm telling the microprocessor to send ASCII character $35 (decimal 5) then to send ASCII 13. I tried to program the PLC to read the value. I set up one line of ladder logic saying if switch one is on run dCusF. The custom function said "A$ = INPUT$(1)". I am assuming this means read input and store in variable A.
I don't have the hardware on my PC to use the RS485 connection on the PLC so I'm having to swap the RS232 cable between the PC and the microcontroller. Will this be affecting it?
I quick response would be grateful because my project is due to be finished by Thursday. ?:-/
Thank you
Scott