The Reform of "Three Special-purpose Devices and Two Lockups" Electronic Control System at the Tunnelling Face in Coal Mines

At the tunnelling face of coal mines,"Three Special-purpose Devices and Two Lockups" is an important measure to prevent gas accident from happening,which involves power supply,ventilation and supervision.Recently,relay protection is applied in the "Three Special-purpose Devices and Two Lockups" Electronic Control System.Since the number of components of relay control system is big,the fault rate is high and the reliability of the system is low,this paper suggests that the relay control system be reformed by PLC in order to raise the reliability of the system and ensure the safe production of coal mines.