2.Programming of PLC

 

Programming of PLC

The PLC manufacturer determines PLC development software. Allen Bradley, Siemens, Schneider and GE each have their own software development platforms for programming their PLC models. Once the platform is determined, the actual programming of the PLC logic can be done in a different method is per IEC61131. The most common methods of PLC programming include Ladder Logic, Function Block, structured text, Sequential Function Chart and Instruction List.

The operating structure of the PLC program is mentioned below.


Load process input image: At initial execution, PLC reads the status of process inputs.

Call Main Routine: After reading the input status PLC goes to Main routine for execution of the PLC program. Main routine contents the sub routine where user can aggregate the PLC program based on application. There can subroutine for analog inputs, outputs, digitals inputs, digital outputs, alarms, manual operation and auto operation.

Load process output image: As per instructions written in the main routine and subroutine process outputs are energized.



Sub Routine: Based on application, there can be number of subroutines. Subroutine are called on main routine. Example is shown below.




Further:https://automation-4-u.blogspot.com/2023/04/3nonc-contact-and-boolean-logic.html














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