I only know that here is to define the input and output length, doubt is: such as the first set of the module "0 x23 0 x1f" said output 4 bytes input 16 bytes, so PLC from where to get the output of 4 bytes needed? Also, if the return from standing below 16 bytes, so PLC PLC after received this 16 bytes how do you know it is 16 bytes corresponding what does that mean?
PLC is one of the biggest doubts: how do you know the sending it module1 or module2 or module3?