hello friends
i am trying to communicate ML-1400 SERIES-A with arduino(ATMEGA328) serially
so i have made arduino as a modbus master and PLC as a modbus rtu slave
i have downloaded the MODBUS MASTER library for arduino from github
so now i have following hardware
ml-1400 series a PLC
arduino freeduino(ATMEGA328)
RS232-TTL CONVERTER(as PLC have RS232 PORT)
i have set channel-2 of my PLC as a modbus rtu slave
AND THE NODE ADDRESS IS 1
do i need to change anything in the library???
when i connect both device serially on the com port of ARDUINO it is showing some unexpected characters
i want to implement the function no-1 and no-2 of modbus specification
i.e read the status of the coils and read the status of the inputs
and for that i have written a simple programm in RS LOGIX(programming software for PLC)
i have uploaded the screen shot of that
i have also uploaded the library for arduino for the reference as well as my program for arduino
please tell me how to fix this
thanks in advance
arduino programm.zip (976 Bytes)
Modbus library.zip (203 KB)