There are other conditions, not necessarily initiated by an operator or the control system, that will cause a Stop Command to be interpreted by a given Stop Group
Missing Connection
If any single device (ERSC or ConveyNet I/P) is missing from a configured Stop Group due to for example unplugged or damaged cable; a Stop Command will be issued to all modules in the Stop Group
Missing PLC
If a PLC establishes a structured instance connection to any single device (ERSC or ConveyNet I/P) within a Stop Group and that connection is subsequently lost to the PLC, a Stop Command will be issued to all modules in the Stop Group
Power Loss
If any individual or multiple modules within a Stop Group has its power disconnected; all remaining powered modules within that Stop Group will recognize this as a Stop Command