The reliability of the industrial computer PLC product itself can be guaranteed, but some incorrect operations in the application will cause a certain impact. I have sorted out some tips in the daily application of industrial computer PLC for everyone, hoping to help everyone in the daily use of industrial computer PLC.
Overvoltage and Overcurrent Treatment of Inverter
1. When the given value is reduced to decelerate the motor, the motor enters the regenerative braking state, and the energy fed back by the motor to the inverter is also high. This energy is stored in the filter capacitor, which increases the voltage on the capacitor and quickly The inverter trips when the setting value of DC overvoltage protection is reached.
The treatment method is: take measures to add a braking resistor outside the inverter, and use the resistor to consume the regenerative electric energy fed back to the DC side by the motor.
1. The inverter has multiple small motors. When an overcurrent fault occurs in one of the small motors, the inverter will give an overcurrent fault alarm, which will cause the inverter to trip and cause other normal small motors to stop working.
The treatment method is: install a 1: 1 isolation transformer on the output side of the inverter, when one or several small motors have an overcurrent fault, the fault current will impact the transformer instead of the inverter, thereby preventing the inverter from falling off. brake. After the experiment, the work is good, and there is no failure of the normal motor to stop before.
Tag input and output for easy maintenance
PLC controls a complex system, and what you can see is the upper and lower rows of staggered input and output relay terminals, corresponding indicator lights and PLC numbers, just like an integrated circuit with dozens of feet. Anyone who does not look at the schematic diagram to repair the faulty equipment will be helpless, and the speed of finding the fault will be particularly slow. In view of this situation, we draw a table based on the electrical schematic diagram, paste it on the console or control cabinet of the equipment, and indicate the electrical symbol corresponding to the number of each PLC input and output terminal, the middle name, that is, similar to the integrated circuit. Function description of the pins. With this input and output table, electricians who understand the operation process or are familiar with the ladder diagram of the equipment can carry out maintenance. But for those electricians who are not familiar with the operation process and can't read ladder diagrams, they need to draw another table: PLC input and output logic function table. This table actually describes the logical correspondence between the input loop (trigger element, associated element) and the output loop (actuator element) in most of the operations. Practice has proved that if you can proficiently use the input and output correspondence table and the input and output logic function table to repair electrical faults, you can easily and freely without drawings.
