Below are the differentiation between implicit and Explicit messaging :
Implicit Exchange Objects:
These objects are automatically exchanged on each cycle revolution of the task associated with the module
Implicit exchanges concern the inputs/outputs of the module (measurement results, information and commands). These exchanges enable the debugging of the counting modules.
Explicit Exchange Objects:
These objects are exchanged on the application's request, using explicit exchange instructions
Explicit exchanges enable the module to be set and diagnosed.