Mine explosion-proof and intrinsically safe programmable control box (explosion-proof tight chain electric control box) is mainly used in mines with explosive mixtures (methane mixtures) and coal dust, and carries out electrical control and monitoring of the electric control system of the underground coal mines through PLC and man-machine interface.

The explosion-proof electric control box mainly consists of SMART-200PLC, isolation barriers, relays, switching power supply, display screen (HMI), together with the external control system.

（The explosion-proof electric control box is mainly composed of SMART-200 PLC, isolation gate, relay, switching power supply, display screen (HMI), and together with the peripheral sensors, it forms a digitalized hydraulic chain tightening electric control system (hereinafter referred to as system).

The system can realize safety interlocking with the three machines on the working face, that is, it accepts the locking inputs from the three machines and has the operation locking outputs to the three machines; the system can constitute a multi-machine centralized control network in various forms in an extremely convenient way to realize remote control and communication, and it can even communicate with other monitoring systems with various protocols and send the data to the ground monitoring center. With simple operation, stable and reliable performance, the system is an ideal electric control system for hydraulic chain tightening device.