Abstract: This paper introduces the application of the EM series programmable controller in the operation of a copper wire rope traction belt conveyor. The system composition and distribution principle are summarized, the system characteristics and implemented functions are described, and a system flowchart and program flow chart are presented. Keywords: Programmable controller; Wire rope traction belt conveyor; Operation 1 Introduction The wire rope traction belt conveyor, as a type of transportation equipment, was put into use in mines in China in the 1970s. It features long transportation distance, large transportation capacity, simple operation, and convenient maintenance, and can be used for horizontal or inclined transportation. As the main shaft hoisting equipment of the No. 1 Coal Mine, the wire rope traction belt conveyor is responsible for transporting coal and personnel; its reliability is directly related to the safe production and the safety of personnel and property in the entire mine. This transportation equipment uses an induction voltage regulator for voltage regulation, which is rectified by a silicon rectifier and then supplied to a DC motor. The operating system is relay-operated. The relay operating system uses many relays, and has even more contacts and connecting lines for implementing logic functions. The original equipment had been in operation for a long time, frequently experiencing component or contact burnout, especially during personnel transport. The contacts of the actuator relays protecting the wire rope traction belt conveyor along the roadway were burned and stuck together, preventing timely shutdown in case of danger – an unacceptable situation. To meet the needs of safe production and high-yield, high-efficiency mines, equipment modification was essential. 2. Features of Programmable Logic Controllers ( PLCs) Hitachi's EM series PLCs are small in size and highly expandable. The memory uses EEPROM chips, allowing for electrical writing and erasure of data without the need for battery-based program retention. PLCs use ladder diagrams for programming, similar to relay operating system diagrams, making them intuitive, easy to understand, and easy to master. They use fewer programmer instructions, are simple to operate, and convenient to use. The internal input/output contacts of the PLC are digital logic operation contacts, not physical relay contacts. They are reliable, stable, and maintenance-free. Because the logic functions are performed by the PLC, complex external connection wiring is eliminated. The status of each line is indicated on the programmable logic controller (PLC) to facilitate understanding of the operating conditions or diagnosing faults. 3. System Composition The PLC consists of a frame, power supply module, CPU module, and input/output modules, housed inside the control panel. The system block diagram is shown in Figure 1. The wire rope traction belt conveyor has automatic, manual, personnel/coal transport, and maintenance operation modes. In automatic mode, as long as the system is in normal operating condition, switching the selector switch to automatic will automatically accelerate the conveyor until it reaches a constant speed, stopping when the transport task is completed. In manual mode, the driver controls the final constant speed, and due to the output voltage limiting function, the rated operating speed cannot be exceeded. The maintenance operation mode is used to check the wear and tear of the traction wire rope and load belt. During system operation, if the conveyor belt at the shaft entrance stops due to a fault, or if the personnel over-limit protection at the shaft entrance or bottom, or the protection along the conveyor roadway is activated, the system will automatically stop and issue an alarm signal. The PLC uses opto-isolated input modules and relay-isolated output modules. The input/output is isolated from the microprocessor, providing strong anti-interference capabilities and resulting in extremely high system stability and reliability. 4. Program Flowchart The program flowchart of the programmable logic controller (PLC) is shown in Figure 2. Before starting the wire rope traction conveyor belt, the PLC software first checks whether each operation meets the requirements. If not, a warning is issued, and the running command is only issued after the conditions are met. During operation, the system constantly monitors the operating status of each input port, reacting immediately to any changes. In case of a fault, an alarm is triggered until operation is interrupted. The system software design prioritizes reset latch instructions for the safety protection circuit to meet the requirement of locking the start-up circuit before handling faults, thereby improving the system's safety and reliability. 5. Conclusion Since the system was modified and put into operation, it has been running stably and reliably. It has reduced the equipment failure rate, decreased equipment maintenance time, and improved production efficiency.