General sequence control algorithm used in programmable logic controller

Abstract

The invention relates to the programming of a programmable logic controller (PLC), in particular to a general sequence control algorithm used in the programmable logic controller. The method is that the programmable logic controller repetitively digitalizes the current input signal, the digitalized data is used as an input parameter for indirect addressing, information required for the next operation and control output of the programmable logic controller is obtained from a datasheet and a corresponding operation is conducted according to the information. The general sequence control algorithm used in the programmable logic controller is not limited by a controller master program (i.e. a controller master scheduling program) and a hardware, and can independently maintain the progress of a customer program (i.e. control program), a customer program algorithm for inputting and outputting signal status, the definition of a supportive data storage structure and the specific implementation method.

Description

technical field [0001] The invention relates to the programming of a programmable logic controller (PLC), in particular to a general sequence control algorithm applied to a programmable logic controller. Background technique [0002] The programming of the current programmable logic controller (PLC) is based on the IEC1131-3 standard, namely LD\IL\ST\SFC\FDB five languages. There are mainly the following ways to realize the specific functions: [0003] 1. Experience-based method: For basic control objects, such as: motors, valves, and hydraulic cylinders, there are fixed program processing modes, while for the realization of system-level control processes, it is completely realized by manual experience programming. The logic control and sequence control are realized by manual programming together. [0004] 2. The truth table solution method based on logic algebra: for logic control or sequence control requirements, convert the sequence control requirements into logic input...

AI Technical Summary

Problems solved by technology

[0008] 1. Since all the control functions are realized based on instruction statement programming, with the changes between different control systems and PLC configurations, the organizational structure and address configuration of the program codes are different, and the program codes cannot be reused.

[0009] 2. In the process of realizing the control function, the designer is subject to arbitrariness and cannot control the quality of the realization process

[0010] 3. Since the control function realization process mainly runs through the whole program in the form of signal interlocking and self-locking, so on-site debugging and each function modification of the program involve multiple parts of the program, and the modification process is irregular, cumbersome and difficult

At the same time, the program is prone to problems such as parasitic logic, dead zone logic and output jitter

[0011] 4. Due to too many human factors in the design process of the control program, the implementation cycle changes greatly, and the final program quality and performance are difficult to control

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