In recent years, with the development of society, PLC programmable logic controller has been widely used in industrial production, but its maintenance methods and techniques, many electricians are not method, the author working in the production line for a long time engaged in maintenance and repair of electrical equipment and management, particularly interested in PLC application development and maintenance work, accumulated experience and techniques for more effective.
PLC inputs and outputs
A small PLC control of a complex system is two rows of staggered up and down the input/output relay terminals, PLC and led that corresponds to the number, like dozens of feet of integrated circuits. Anyone if you do not see the schematics to repair faulty equipment, helpless, look goes slowly. In view of this situation, we according to the schematic drawing a table, attached to the equipment console or control cabinet, marked each PLC input/output terminal number with the corresponding electrical symbols, Chinese names, such as integrated circuit pin function description. With this input-output table, to understand the operation the electrical ladder diagram or familiar with the equipment, you can expand and repair. But for those not familiar with the procedure, look for electrical ladder diagram, you need to create a form: PLC input/output logic function table. The table actually shows a bulk operation input circuit (trigger components and associated components) and output circuit (actuator) corresponds to the logical relationships. Practice has proved that if you can use input and output the corresponding table table and input/output logic functions, repair electrical faults, without drawings, can easily.