The PLC Instruction List (IL) and assembly language have significant differences in programming. Here is a detailed comparison of the two:
1. Definition and Use
• PLC Instruction List (IL):
• It is a commonly used text-based programming language in PLC (Programmable Logic Controller) programming.
• It represents control programs in a list of instructions similar to assembly language, used to describe functions, function blocks, and the behavior of programs.
• It is often used as a foundational programming language, allowing easy conversion from other programming languages to IL.
• Assembly Language:
• It is a low-level language oriented towards machines, typically designed for a specific computer or series of computers.
• Assembly language directly describes machine instructions, making them easier to remember and understand than machine code.
• It serves as a language processing system in system software, being the best starting point and most effective way to understand the entire computer system.
2. Syntax and Structure
• IL:
• The instructions are simple and direct, with each instruction starting on a new line, consisting of an operator followed by its operands.
• It lacks structured control statements like loops and conditional statements found in high-level languages, which may make writing complex logic relatively cumbersome.
• Assembly Language:
• It consists of opcodes and operands, with each opcode corresponding to a machine instruction.
• Assembly language retains the advantages of machine language, characterized by directness and simplicity.
3. Programming Difficulty and Readability
• IL:
• For applications requiring precise control of underlying instructions, IL may be a better choice.
• However, for beginners, the syntax and structure of IL may be obscure, presenting a steep learning curve.
• The lack of structured control statements may increase programming complexity, making maintenance difficult.
• Assembly Language:
• When writing efficient programs that require precise control over hardware, assembly language has significant advantages.
• However, assembly language is dependent on specific processor architectures and is not universal, making it non-portable between different processor architectures.
In summary, there are significant differences between PLC Instruction List IL and assembly language in terms of definition, syntax structure, programming difficulty, and readability. The choice of language depends on the specific application scenario and programming requirements.