Connect plc to arduino shield ethernet w5100

hi, with my arduino shield ethernet w5100 I would like to acquire a datum from a PLC, which would be the program that the machine is using at that moment, The program in use is written in a word of the PLC. There are about 20 programs.
With Arduino then, I will do different actions depending on the program acquired.
I tried with the modbus library, but it doesn't work for me. Do I need to use other hardware?

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.