The programming languages supported by the ControlLogix module comply with the IEC61131-3 standard, mainly including the following:
Ladder diagram:
Ladder diagram is a graphical language that is intuitive and easy to understand, and is one of the most commonly used and widely used programming languages. It adopts the terms and graphic symbols of relay contacts, coils, series, parallel, etc., and adds new functions and logical symbols, which are intuitive, easy to learn, and easy to understand.
Structured Text:
Structured text is similar to high-level computer languages, using expression structures composed of operators and operands to describe the behavior of functions, functional blocks, and programs. Returns a value when executing an expression, suitable for complex unconventional arithmetic operations, specialized arrays, or looping tables.
Function block diagram:
Functional block diagrams use graphical logical symbols similar to Boolean algebra to represent control logic and configuration process control. It establishes the program structure through the connections between functional blocks and is an instrument control configuration method introduced into DCS systems, particularly suitable for scenarios such as process control, drive control, and closed-loop control.
Sequential functional diagram:
A sequential functional diagram is similar to a flowchart of sequential control, which refines the workflow into steps, provides the overall structure, and coordinates batch oriented processes. It is particularly suitable for control requirements with clear process steps, such as high-level management of multiple operations, repeated operation sequences, and batch processing of a large number of repeated operations.
These programming languages have their own characteristics and can be selected and used according to different application scenarios and the programming habits of engineering and technical personnel. The number of instructions, instruction symbols, and parameters in each language also vary, and some instructions are only used for certain control scenarios. For example, the timer instructions TON and TONR for ladder diagrams and structured text have different forms, and sequential function diagrams do not support ASCII instructions. Therefore, when choosing a programming language, it is necessary to comprehensively consider the specific situation and requirements of the application.