Khl1 type emergency stop switch along the line is selected. It is used for the emergency locking protection along the belt conveyor, with the function of fault location identification, and is also used as the wiring cavity of the underground protection sensor elements. It is used for centralized wiring of intrinsically safe input signals such as signals, protection, control commands, etc. it can concentrate all control signal lines in a multi-core cable, saving a lot of signal cables. The protection transmits switching signal and has strong anti-interference ability. When the locking switch acts, the PLC controller outputs an alarm and sends out an emergency stop command.