EUCHNER CES Category 4, Non-Contact Safety Systems are used to monitor the position of movable machine guarding by means of Inductive Coding. These systems are designed for use in areas where a high level of tamper resistance and safety is required. These systems feature an inductive read head with integral evaluation unit / safety module, and a digitally coded actuator. Unlike universally coded magnetic switches, the CES actuators are uniquely coded and cannot be bypassed by any means. The safety switch CET-AR with guard locking is based on the proven transponder principle. The CET-AR has an integrated evaluation module making it a complete package. The CET1-AR, originally a mechanically locking device, where applying power unlocks the switch, is now also available in the electrically locking CET2-AR, where applying power locks the switch, and CET3-AR with a door monitoring contact.