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Messages - Pneuman

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Technical support / MASTER-SLAVE Communication
« on: October 02, 2006, 02:27:48 PM »
I have decided to use the READMODBUS & WRITEMODBUS commandS. The example works fine and the commands worked fine when I installed them on the master PLC. I am able to input on one PLC and output to the other PLC.  I am still not able to read my ADC channels from the slave to the master though.  I programmed in the slave DM[1]=ADC(1)and checked the on line monitor to make sure I had a changing value when I adjusted the analog input. That worked fine. Then I programmed into the master PLC:    DM[1]=READMODBUS(3,1,1001). I also tried using 1000, 1002 none of which gave me my #value for the ADC(1) when I monitored the master PLC program and changed the analog input on the slave.  I also tried to have the READMODBUS command = an alphanumeric variable directly with no luck. I am not a programmer but this seems straightforward enough. Can you help?

It works now. I used the README2 command and I am able to read all 8 ADC into the master plc starting address 1000 worked  for DM[1-8] ? offset 1000-1

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Technical support / PLC-PLC Communication
« on: September 30, 2006, 02:41:04 PM »
I need help. I Have two T100MD series PLC hooked together RS485 connections. I ran the sample program: Remote IO series M, and the PLC talk to each other, so I know that works.

I have tried to adapt the program to read the A/D channels from the Slave PLC and can't make it work. As an alternative I also tried to transfer the interger variables representing the A/d channels to the Master PLC without success. Could you give me a sample program. I used command line RVIK* to read the variable but does it need to be converted back from a hexadecimal digit? I also tried RVSOB01* to read the a/d channel 1 directly but I don't know if it came back and I don't know how to convert it back to a Variable represented by A-D. I think my problem might be that I don't know how to convert the string reply back into a numerical variable that I can manipulate. Any suggestions?

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