Application of the hottest PLC in the liquid resis

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Application of PLC in liquid resistance starter of mill control cabinet

2 sets in our factory Ф 2.4mx7m and 2 sets Ф The 2.2mx6.5m mill is designed with a liquid resistance starter controlled by PLC. It vibrates (pointer jitters) during loading. After several years of use, the effect is good

1 the function of the liquid resistance starter should have debugging and operation control to facilitate maintenance and debugging

2) the upper and lower limits of the pole plate must be controlled. When the mill starts, the pole plate starts to run downward from the upper limit affected by the development of the global transportation industry. When it reaches the lower limit position, the mill starts and the rotor short-circuit contactor 5 automatically closes. Then the polar plate starts to run upward and returns to the upper limit position

3) there must be enough liquid level, which cannot be lower than the specified level

4) the liquid temperature cannot be lower than or higher than the specified temperature

5) when the incoming camera is put into operation, the short-circuit contactor K is automatically disconnected, and when the incoming phase

machine exits, the short-circuit contactor K is automatically closed

6) when the change-over switch is in the running position, the polar plate is in the upper limit position, and the liquid level and temperature are normal, PLC will give the start-up permission signal, otherwise it will give the start-up prohibition signal. During normal operation, if one of the above conditions is not met, PLC will give a fault signal and the main circuit will trip automatically

7) if the polar plate cannot run downward after the mill is started, the PLC will give a signal after a delay of 30s, and the main circuit will trip automatically

2 selection of PLC

considering the small number of input and output points of the whole control system, Mitsubishi Corporation of Japan selected the FMR PLC of a master batch company created by mixing graphene powder with resin as the control center. The machine has 12 point input and 8 point output, which fully meets the system requirements. The control principle is shown in Figure 1

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