Method and device for monitoring and recording component and variable in PLC (Programmable Logic Controller) system

Abstract

The invention discloses a method and a device for monitoring and recording components and variables in a PLC (Programmable Logic Controller) system. The method comprises the steps of setting components and variables to be monitored and recorded to generate a list of components and variables to be monitored and recorded; obtaining values of components and variables to be monitored and recorded in the list of components and variables to be monitored and recorded according to preset monitoring and recording conditions and the list of components and variables to be monitored and recorded and storing the values according to a preset format; and obtaining change values of the components and the variables according to the stored values of the components and the variables to be monitored and recorded. The method and the device disclosed by the invention have the beneficial effects that the components and the variables which are wanted to be monitored and recorded can be defined; the monitoring and the recording of the values of the components and the variables can be realized; the mutation values of the components and the variables which only last one scanning cycle can be accurately recorded and captured; and by monitoring and recording system errors, the errors which occur in whichever line and whichever instruction can be positioned, quick positioning can be realized after problems occur and the time for analyzing and solving the problems is effectively shortened.

Description

technical field [0001] The present invention relates to the field of PLC (Programmable Logic Controller), more specifically, to a method and device for monitoring and recording components and variables in a PLC system. Background technique [0002] PLC (Programmable Logic Controller, Programmable Logic Controller) is one of the most important, most popular, and most widely used industrial controllers. With the continuous growth of the demand for automation control of industrial equipment, the field of PLC application is rapidly expanding. [0003] Monitoring and recording the values ​​of components and variables in the PLC system, on the one hand, plays an important role in improving the usability and reliability of PLC products, on the other hand, it can facilitate users to find and locate problems that occur during product operation, Shorten user program debugging and problem solving cycles. Among them, the components in the PLC system refer to the defined soft component...

AI Technical Summary

Problems solved by technology

[0005] 1. Lack of records of changing values ​​of components and variable changes

[0006] 2. Obtaining the value of components and variables by means of timing monitoring, it is impossible to obtain the change value of components and variables in each scan cycle during the operation of the PLC system; and it is difficult to monitor the value of components and variables when they only last for one scan cycle Mutated values, it is difficult to provide more help for the exceptions that occur during program running and debugging

[0007] 3. Users cannot freely configure the components and variables that need to be monitored and recorded

[0008] 4. Due to the limitation of communication speed and communication medium between PLC system and PLC products, it is impossible to monitor the values ​​of components and variables in real time

[0009] 5. When a system error occurs in the PLC, there is no error tracking and recording function. It is difficult to locate the error in which line and instruction only based on the system error code stored in special special components and variables.

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