Rockwell Automation Safety Mat System MatGuard Control Unit Complete your pressure sensitive MatGuard safety system and minimise risk injury to personnel in hazardous areas with the 440F-C4000P Matguard Control Unit. This device is designed to work within the MatGuard presence sensing system and monitor any number of mats which are connected together, forming a safeguarded zone up to a total area of 100m². The unit interfaces with the control circuitry of the machine and includes two safety relays for control redundancy. The 440F Safety Mats offer whole body detection on the sensing surfaces. When the surface is clear the controller sends a signal to the control circuit of the machine. Conductive plates within the mat touch when the mat is stepped on and resistance in the circuit falls to zero. The controller then sends a shutdown signal to the machine, preventing risk of injury to operators within the dangerous area.