Balluff, Germany, introduces the zone limit switch for all-round safety. Securing the operating work envelope of a robot requires not only physical barriers (eg, an interlocked fence), but also a system which safely limits the zone of movement. In many cases, safety circuits are necessary which are essentially independent of the controller and software. The work envelope is the permissible extension zone of the robot. The safety zone is the area which the robot is not permitted to enter under any circumstances. A circular collar is attached to the robot axis which needs to be secured. Round cams. attached to the collar determine the operating work envelope and safety zone of the robot. The cams actuate safety switch elements which can be 2- or more channels, depending on the requirements of the safety circuit. Balluff multiple position limit switches with right plunger and safety switch inserts per VDE 0 113 ate ideal components for constructing safety apparatus for man and machine.