Design of an instantaneous monitoring system of mine roadway sectio

Manual measuring method for mine roadway section is time-consuming and laborious with big error, and existing measuring instruments of roadway section are poor in measuring speed and cannot realize real-time monitoring by upper computer. A design scheme of instantaneous monitoring system of mine roadway section was proposed based on PLC and ZigBee network. PLC of the system outputs two high-speed pulse sequences at 6 400 bit/s to control stepper motor to rotate and drive pulsed laser rangefinder to range respectively. High-speed counters of HC0, HC1 count two pulse sequences respectively. Step angle of the stepper motor is 0.45°. After laser rangefinder rotates 360°, the PLC calculates perimeter and area of roadway section and sends the results to upper computer through ZigBee network for real-time display. The experimental results show that the system updates to display perimeter and area of roadway section every 10 seconds. Relative error of perimeter measuring is no more than 0.5%, and the one of area measuring is no more than 0.9%.