The SI-LS31 series Safety Limit Switch is plunger actuated type-1 interlocking device used to monitor the position of a guard, gate, door or other physical barrier separating an individual from a hazard. The safety limit switches to monitor the position of a guard to detect the movement, opening or removal. Safety switches will issue a signal to the machine control system to prevent or stop (halt) hazardous situations when the guard is not in the proper position. This safety switch is designed for non-locking guarding applications, unless another means of locking is provided. The safety limit switch are is considered a type-1 interlocking device per ISO 14119 that are mechanically actuated by an uncoded rotary or linear actuator (cam or dog) typically mounted on or part of the guard. It can be used for safety or non-safety interlocking and position monitoring. Mechanically coded actuators use two independent operating elements to minimize intentional tampering or defeat.