Modular control device with redundant channel units

A peripheral module for a modular control device, the peripheral module comprising:

• a plurality of redundant channel units;
• an output unit, wherein:
• the output unit is configured to set one or more outputs in response to control by the channel units,
• each channel unit of the channel units includes (i) a processing unit and (ii) a plurality of failure revelation units configured to monitor a state of the channel unit,
• the processing units are arranged to respectively stimulate ones of the failure revelation units, and
• the failure revelation units of each channel unit are collectively arranged to control setting of the outputs of the output unit in response to the stimulation and monitoring;
• and
• a bus disconnection unit configured to disconnect signal wires of a communication bus between the peripheral module and a head module of the modular control device in order to shut down the communication bus in a fail-safe manner.

A method of operating a head module including a plurality of redundant channel units that each includes a processing unit and a plurality of failure revelation units, the method comprising:

• for each of the channel units, monitoring, using the corresponding failure revelation units, a state of the channel unit;
• for each of the channel units, continuously stimulating, using the corresponding processing unit, at least one of the corresponding failure revelation units;
• and
• based on the stimulation and the monitoring, controlling a bus disconnection unit to shut down a communication bus that provides a communication link between the head module and one or more peripheral modules, wherein shutting down the communication bus includes disconnecting signal wires of the communication bus in order to shut down the communication bus in a fail-safe manner.