HI friends

        I have some problem while communicating  modbus with microcontroller

i am using tia portal v12 sp1 and my modbus communication board is CB1241 ,,,,where i configured  MB commn load and MB master  and  i used pointer address P#M300 word 16

                                         while communicating   problem 1>>>> i couldnt identify data  when i looking at  the watch table it is some vale in 8 bit and it is alternatively changing ,please help me how i read this into a real value

problem 2>>>>>when i communicating other device  i am taking address eg MD350   ,,,when i take this address to scada  while i switch off my sensor device  it will not get reset last value will be show and i tried timer but it couldnt do please help me

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Split from Modbus configuration and programing in Step7 with S7-300 PLC as master.

Hello jhon;

Con you tell us if you have tried to communicate with your microcontroller (as a Modbus slave) using a test master, such as Modscan32?

First, establish that it is working properly on Modbus. Then we can start examining problems with your addressing or programming

Hope this helps,

Daniel Chartier