System for controlling PLC (Programmable Logic Controller) analog input and output and method for controlling analog output

Abstract

The embodiment of the invention discloses a system for controlling PLC (Programmable Logic Controller) analog input and output and a method for controlling analog output. The system comprises a PLC main control module and an analog input and output extending module, wherein the analog input and output extending module comprises an input unit, an output unit, a communication unit, a control unit, a first multiplexer and a second multiplexer; the PLC main control module is used for sending control signals to the control unit; the control unit is used for giving monitoring instructions to the first multiplexer according to the control signals sent by the PLC main control module; and the first multiplexer is used for feeding back the signals of a specific output unit to the control unit via the second multiplexer according to the monitoring instructions given by the control unit and feeding back to the PLC main control module via the control unit. Accordingly, the embodiment of the invention also discloses the method for controlling the PLC analog output. The system and the method which are disclosed by the invention have the beneficial effects that: the signals of an analog output unit are selectively monitored by adopting the multiplexers, therefore, the system reliability is increased and the PLC analog input interface space is saved in the meantime.

Description

technical field [0001] The invention relates to the field of electronic communication, in particular to a PLC analog quantity input and output control system and an analog quantity output control method. Background technique [0002] Programmable logic controller (PLC, Programmable Logic Controller) is an electronic device specially designed for application in industrial environments, and has been widely used in the field of industrial automation. In the automation system, the analog input interface and the analog output interface are the most commonly used electrical interfaces. Generally, the analog input signal is measured through the analog input interface; the external actuator is connected through the analog output interface. However, during the working process of the system, due to many reasons such as overload, surge, and aging of components, the analog output of the analog output interface will cause errors. If these faults cannot be found and eliminated in time, i...

AI Technical Summary

Problems solved by technology

However, during the working process of the system, due to many reasons such as overload, surge, and aging of components, the analog output of the analog output interface will cause errors. If these faults cannot be found and eliminated in time, it will cause irreparable damage to industrial production. Loss

The usual practice is to monitor the analog output by connecting the feedback monitoring circuit to the analog output interface, which often requires the help of an external auxiliary circuit, and the analog input interface on the terminal block needs to be occupied when inputting the feedback signal, which compresses the Terminal row space, resulting in higher system manufacturing costs

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