Typical methods for an operator or the control system to issue a Stop Command is either via hardwired Stop push-button or via network command from PLC as shown:

Hard-Wired Push-Button

ERSC Module

You can connect Stop Command buttons to either the Left or Right Control Ports on an ERSC in the Stop Group. Stop buttons require 2 sets of contacts and connect to the 2 inputs on the control port. If ANY of these contacts become opened on a given module; it will generate a STOP Command to ALL modules within the group over the 2 communication rings.

CNIP Module

For the CNIP module, there are dedicated inputs to use to connect a Stop Command button. See Wiring Examples for details on the inputs reserved for this function

Remote PLC

If a PLC is connected to at least one module in a Stop Group; it can issue a Stop Command to that module and all modules within that group will recognize this as a Stop Command. Even if the PLC is connected to more than one module in a Stop Group, it only has to issue the Stop Command to only one module in order to Stop the whole Stop Group.