How to add custom functions to Allen - Bradley HMI programming? - Blog

Hey there! I'm an Allen-Bradley HMI supplier, and I've been in this game for quite a while. One question I get a lot from customers is how to add custom functions to Allen-Bradley HMI programming. Well, you've come to the right place! In this blog post, I'm gonna walk you through the whole process step by step.

First off, let's talk about why you might want to add custom functions to your Allen-Bradley HMI. The stock features are pretty great, but sometimes you need something extra to fit your specific needs. Maybe you've got a unique process in your factory, or you want to add some special reporting capabilities. Custom functions can give you that extra edge and make your HMI work exactly the way you want it to.

Understanding the Basics of Allen-Bradley HMI Programming

Before we dive into adding custom functions, it's important to have a solid understanding of the basics of Allen-Bradley HMI programming. The Allen-Bradley HMIs use a programming environment called FactoryTalk View Studio. This is where you'll create your screens, set up your tags, and write your scripts.

If you're new to FactoryTalk View Studio, don't worry! It's got a pretty user-friendly interface, and there are plenty of resources out there to help you learn. You can find tutorials on the official Allen-Bradley website, and there are also some great online communities where you can ask questions and get advice from other programmers.

Preparing Your HMI for Custom Function Development

The first step in adding custom functions is to make sure your HMI is set up correctly. You'll need to have the right hardware and software installed, and your HMI should be connected to your network.

Let's take a look at some popular Allen-Bradley HMI models that are great for custom function development. Check out the Allen Bradley 2711C T3M, Allen Bradley 2711P-RR256, and Allen Bradley 2711P-T15C22D9P. These models offer a good balance of performance and features, and they're compatible with FactoryTalk View Studio.

Once you've got your HMI up and running, you'll need to create a new project in FactoryTalk View Studio. This is where you'll start building your custom functions.

Creating Custom Functions in FactoryTalk View Studio

Now, let's get into the nitty-gritty of creating custom functions. In FactoryTalk View Studio, you can use Visual Basic for Applications (VBA) to write your custom scripts. VBA is a powerful programming language that's easy to learn, especially if you have some basic programming experience.

Here's a simple example of how you might create a custom function to calculate the average of two numbers:

Function CalculateAverage(num1 As Double, num2 As Double) As Double
    CalculateAverage = (num1 + num2) / 2
End Function

To use this function in your HMI project, you'll need to add it to a module in FactoryTalk View Studio. Here's how you do it:

Open your project in FactoryTalk View Studio.
Go to the "Scripting" tab and click on "Modules".
Right-click on the module list and select "Insert Module".
Give your module a name, like "CustomFunctions".
Open the new module and paste your custom function code into it.

Once you've added your custom function to a module, you can use it in your HMI scripts just like any other function. For example, you might use it to update a text box on your screen with the average of two sensor readings.

Testing and Debugging Your Custom Functions

After you've written your custom functions, it's important to test them to make sure they work correctly. FactoryTalk View Studio has a built-in debugger that you can use to step through your code and find any errors.

Here are some tips for testing and debugging your custom functions:

Use breakpoints: Set breakpoints in your code to pause the execution at specific points. This can help you see what's going on in your function and identify any issues.
Check your variables: Make sure your variables are being assigned the correct values. You can use the debugger to inspect the values of your variables at different points in your code.
Test different inputs: Try passing different values to your custom function to make sure it works correctly in all cases.

Integrating Custom Functions into Your HMI Screens

Once you've tested and debugged your custom functions, it's time to integrate them into your HMI screens. You can use your custom functions in scripts that are associated with buttons, timers, or other screen objects.

For example, you might create a button on your screen that, when clicked, calls your custom function to perform a calculation and update a text box with the result. Here's how you might do it:

Allen Bradley 2711P-RR256

Create a button on your HMI screen.
Double-click on the button to open its properties.
Go to the "Events" tab and select the "Mouse Up" event.
Click on the "..." button next to the event to open the script editor.
Write a script that calls your custom function and updates a text box with the result.

Dim result As Double
result = CalculateAverage(10, 20)
ScreenItems("TextBox1").Text = result

Tips and Tricks for Adding Custom Functions

Here are some tips and tricks to help you add custom functions to your Allen-Bradley HMI programming more effectively:

Keep it simple: Start with simple custom functions and gradually build up to more complex ones. This will make it easier to learn and debug your code.
Use comments: Add comments to your code to explain what it does. This will make it easier for you and other programmers to understand your code in the future.
Reuse your code: If you find yourself writing the same code over and over again, consider creating a reusable function. This will save you time and make your code more organized.

Conclusion

Adding custom functions to Allen-Bradley HMI programming can be a great way to customize your HMI and make it work exactly the way you want it to. By following the steps outlined in this blog post, you should be able to create and integrate your own custom functions in no time.

If you're interested in purchasing an Allen-Bradley HMI or have any questions about custom function development, feel free to reach out. We're here to help you find the right solution for your needs and ensure that your HMI project is a success.