PLC Programming war among FBD, Ladder Logic and ST?

Ladder Logic, Function Block, and Structured Text are all commonly used programming languages for PLCs (Programmable Logic Controllers), and the choice of which one is best depends on the specific requirements of the application and the skills and preferences of the programmer or maintenance person.

Ladder Logic:

Pros:

• Easy to understand: Ladder Logic is graphical and resembles electrical schematics, making it simple and intuitive for those with an electrical background to understand.
• Fast to develop: Ladder Logic can be created quickly, which makes it ideal for simple applications that don’t require complex algorithms.
• Widely used: Ladder Logic is the most widely used programming language for PLCs, and there is a large community of users and resources available to support it.

Cons:

• Limited functionality: Ladder Logic is not well suited for complex applications, as it lacks the ability to easily handle complex algorithms or calculations.
• Not ideal for troubleshooting: Ladder Logic can be difficult to troubleshoot, especially when it comes to complex systems, as it is not always easy to see the logic behind a particular sequence of events.

Function Block:

Pros:

• Modular: Function Blocks allow for the creation of reusable blocks of code, which can make it easier to develop and maintain complex applications.
• Scalable: Function Blocks can be easily combined to create larger, more complex applications, making it ideal for large-scale projects.
• Good for troubleshooting: Function Blocks are easier to troubleshoot than Ladder Logic, as the code is more explicit and easier to understand.

Cons:

• Steep learning curve: Function Blocks can be more difficult to understand for those without a programming background, as it requires a deeper understanding of programming concepts.
• Slower to develop: Function Blocks can be slower to develop than Ladder Logic, as it requires more explicit coding.

Structured Text:

Pros:

• Powerful: Structured Text is a powerful programming language that can handle complex algorithms and calculations.
• Good for complex applications: Structured Text is ideal for complex applications that require complex logic or mathematical operations.
• Easy to troubleshoot: Structured Text is easier to troubleshoot than Ladder Logic, as the code is more explicit and easier to understand.

Cons:

• Steep learning curve: Structured Text requires a deeper understanding of programming concepts, which can make it more difficult for those without a programming background to understand.
• Slower to develop: Structured Text can be slower to develop than Ladder Logic, as it requires more explicit coding.

In conclusion, for maintenance people, a graphical programming language like Ladder Logic is usually preferred, as it is easier to understand and maintain, especially for simple applications. For programmers, a more powerful programming language like Structured Text or Function Blocks may be preferred, as it allows for the creation of more complex applications. Ultimately, the choice between these programming languages will depend on the specific requirements of the application, the skills and preferences of the programmer or maintenance person, and the available resources and support in the particular industry or field.