Refer to Diagnostic class (standard): 3
This diagnostic message is reported if a TM5 or TM7 reports a detected error in its status byte (ModuleOK).
DiagExtMsg: Contains the name of the module that is reporting a detected module error. If the name is longer than 14 characters, then the module name starts with ".." followed by the last 12 characters.
If no name could be detected, then the slot number of the module is displayed.