PLC coal machine control system

A PLC coal machine control system, characterized in comprising:

• PLC control unit, weighing unit one, weighing unit two, drive unit, frequency converter, belt motor and velocity measurement unit;
• the PLC control unit is electrically connected with weighing unit one and weighing unit two, and is used to make real-time collection of the weight value of the two units, and the instantaneous weight is gained whereby;
• the PLC control unit is electrically connected with drive unit, frequency converter and velocity measurement unit, and is used to make real-time collection of the output signal of drive unit, velocity of frequency converter and the velocity detected by velocity measurement unit;
• the drive unit is electrically connected with the PLC control unit, which drives the drive unit to run the belt motor and the coal volume of the belt is adjusted thereby;
• wherein the PLC coal machine control system further comprises an alarm unit, the alarm unit is electrically connected with PLC control unit, and the PLC control unit sends a precaution signal after receiving fault type, and the alarm unit sends an alarm or acts on tripping after receiving the precaution alarm;
• wherein the fault type comprises;
• weighing unit fault:
• monitoring the signal output of the weighing unit, when the output value is greater than the maximum value and less than the minimum value, the alarm unit will be triggered to send an alarm, at the same time, the control system is changed to volume mode and takes the volume quality of ten seconds ago;
• PLC control unit battery fault:
• monitoring the battery voltage of the PLC control unit, when a low voltage appears, the alarm unit will be triggered to send an alarm;
• frequency converter fault:
• when the system detects the frequency alarm or the fault signal is sent, the alarm unit is triggered to send an alarm and trip;
• While if 3 times of fault reset requested within 10 seconds and if the fault is solved, the system doesn't trip;
• the coal feed rate request disconnection fault:
• the system delays 3 seconds to trigger the alarm unit for alarm, and the system is based on the set minimum coal amount operation;
• the belt motor fault:
• when the system detects the electric current of the belt motor is too high, the alarm unit is triggered to send an alarm and the system sends an alarm after 5 seconds;
• the coal amount fault:
• when the system detects the difference between the actual coal feed rate and the request coal feed rate is greater than 0.25 t/h, and the alarm unit is triggered to send an alarm after 45 seconds.