If you're looking to improve your PLC programming skills, creating custom functions and libraries can be a game-changer. With custom functions, you can create reusable blocks of code that perform specific tasks, saving you time and effort in the long run. Libraries, on the other hand, allow you to organize your functions and make them easily accessible to other programmers. In this article, we'll show you how to create custom functions and libraries in PLC programming.

Whether you're a beginner or an experienced programmer, creating custom functions and libraries can help you streamline your programming process and improve the quality of your code. By creating reusable blocks of code, you can reduce the amount of time you spend writing code and minimize the risk of errors. Additionally, libraries make it easier to share your code with other programmers, making collaboration and teamwork more efficient.

In this article, we'll cover the basics of creating custom functions and libraries in PLC programming. We'll show you how to create functions that perform specific tasks, how to organize your functions into libraries, and how to make your libraries easily accessible to other programmers. Whether you're working on a small project or a large-scale industrial automation system, custom functions and libraries can help you improve your programming skills and make your code more efficient.

Understanding Custom Functions in PLC Programming

Custom functions in PLC programming allow programmers to create their own functions that can be used repeatedly in different programs. This can save time and effort by eliminating the need to rewrite the same code over and over again. Custom functions can also improve program readability and organization by breaking down complex logic into smaller, more manageable pieces. To create a custom function, the programmer must first define the inputs and outputs of the function. This can be done using variables or tags, depending on the programming language and platform being used. Once the inputs and outputs are defined, the programmer can write the logic for the function using any of the available programming instructions and operators. Custom functions can be stored in libraries, which are collections of reusable functions that can be accessed by multiple programs. Libraries can be created and managed using specialized software tools or integrated development environments (IDEs). Some PLC platforms also provide built-in libraries that contain commonly used functions, such as mathematical operations and string manipulation. When using custom functions, it is important to ensure that they are properly documented and tested. Documentation should include information on the function's purpose, inputs, outputs, and any relevant assumptions or limitations. Testing should involve verifying that the function behaves as expected under a variety of input conditions. In summary, custom functions are a powerful tool for improving the efficiency, readability, and organization of PLC programs. By creating reusable functions and storing them in libraries, programmers can save time and effort while also improving the quality and maintainability of their code.

Creating Custom Functions

Custom functions are an important part of PLC programming. They allow you to extend the functionality of the programming language and create your own functions that can be used in your programs. Here are the steps to create custom functions in PLC programming:

• Define the function signature: The function signature defines the inputs and outputs of the function. This includes the data types of the inputs and outputs.
• Write the function code: Once you have defined the function signature, you can write the code for the function. This can be done in any programming language that is supported by the PLC.
• Create the function library: Once you have written the function code, you need to create a function library that contains the function. This library can be loaded into the PLC and used in your programs.

When creating custom functions, it is important to follow best practices to ensure that your functions are reliable and efficient. Here are some tips:

• Use descriptive function names: Use descriptive names for your functions that accurately describe what the function does.
• Document your functions: Document your functions with comments that describe the function signature, inputs, outputs, and any other important details.
• Test your functions: Test your functions thoroughly to ensure that they work as expected and handle all possible inputs and outputs.

By following these steps and best practices, you can create custom functions that extend the functionality of the PLC programming language and make your programs more efficient and reliable.

Using Custom Functions in Libraries

Custom functions can be stored in libraries for easy access and reuse in PLC programming. Libraries are collections of functions that can be used across multiple programs, making it easier to maintain and update code. Here are some benefits of using custom functions in libraries:

• Reduced programming time: Libraries can save time by providing pre-written code that can be easily integrated into new programs.
• Consistency: Libraries help ensure that the same functions are used consistently across multiple programs, reducing the risk of errors.
• Easier maintenance: By storing functions in libraries, any updates or changes can be made in one place, making it easier to maintain and update code.

To use custom functions in a library, you must first create the library and add your custom functions to it. Once your functions are stored in the library, you can easily access them from any program that uses the library. Here are the basic steps for using custom functions in a library:

1. Create a new library: To create a new library, open your programming software and create a new project. In the project, create a new library and give it a name.
2. Add custom functions to the library: Once your library is created, you can begin adding custom functions to it. To add a function, create a new function block and write your custom code.
3. Save the library: After you have added your custom functions to the library, save the library to make it available for use in other programs.
4. Use the library in other programs: To use the custom functions in other programs, simply add the library to your project and call the functions from within your program.

By using custom functions in libraries, you can save time, reduce errors, and make it easier to maintain and update your code. With a little planning and organization, you can create a library of custom functions that can be used across multiple programs, making your programming more efficient and effective.

Benefits of Custom Functions and Libraries

Custom functions and libraries are essential tools for PLC programming. They provide numerous benefits that make the programming process more efficient and effective. Here are some of the key benefits of using custom functions and libraries:

• Reusability: Custom functions and libraries can be reused across multiple projects, saving time and effort in the long run. Instead of writing the same code repeatedly for different projects, you can simply reuse the existing code, which reduces development time and minimizes errors.
• Modularity: Custom functions and libraries promote modularity by breaking down complex tasks into smaller, more manageable components. This makes it easier to develop, test, and maintain the code, as well as to update or modify it in the future.
• Consistency: Custom functions and libraries ensure consistency in the code by enforcing standardization and best practices. This reduces the risk of errors and makes the code more readable and maintainable.
• Scalability: Custom functions and libraries make it easier to scale the code by adding or removing components as needed. This allows the code to grow and adapt to changing requirements without requiring a complete rewrite.
• Collaboration: Custom functions and libraries promote collaboration by allowing multiple programmers to work on the same project simultaneously. This reduces development time and ensures that the code is consistent and well-documented.

Overall, custom functions and libraries are essential tools for PLC programming that offer numerous benefits. They promote reusability, modularity, consistency, scalability, and collaboration, which make the programming process more efficient and effective.

Conclusion

Creating custom functions and libraries in PLC programming can be a challenging task, but it can also be a rewarding experience. By extending the library of PowerCenter functions, you can create custom functions to use in transformation and workflow expressions, which can significantly improve the efficiency and effectiveness of your PLC programs.

When creating custom functions, it is essential to consider the PLCopen concept, which includes both level and edge-controlled functionalities. By following this concept, you can ensure that your custom functions are compliant with the IEC 61131-3 2nd Edition, which means that they are compatible with most PLC platforms.

Additionally, when creating custom libraries, it is crucial to use symbolic names for the operands and tags in the programming. This will make the program layout clearer and simplify troubleshooting, which can save you time and effort in the long run.

Finally, when creating custom functions and libraries, it is essential to have a good understanding of the problem you are trying to solve, the platform capabilities, and your long-term goals. By considering these factors, you can create custom functions and libraries that are efficient, effective, and scalable, which will benefit your manufacturing environment in the long run.