Making light work of function blocks
03 February 2021
If you’ve ever had to integrate an IO-Link device into any kind of automated system, the chances are you’ll have had to create a function block. Time savers as they are, function blocks are still rather a tedious part of the job.
Function blocks are capsules of information that simplify PLC programming and can even replace hardwired physical components for common tasks like timers or counters.
To create a function block, an engineer will write some code and specify the inputs and outputs to that set of instructions. Then, the whole thing is compiled into a library, along with any other supporting files that help it to work. Once it has been fully tested, the function can be called on repeatedly by the PLC without needing to repeat the base code. The function block must be fully documented so that anyone who uses it later also understands how it works.
All this takes time, and that means cost. You might have invested hours, and more likely days, depending on the task in hand and the complexity, to write and test function block functionality. Even then, you still need to create the library and document the block.
I’ve had function libraries sent over to me that have been created in a rush by a colleague to help me solve a problem. Without the documentation to support the block, I’ve needed to spend considerable time understanding how to incorporate it into my code. If specific types of data structures have been used in the function blocks that are not already part of the library, then you must spend extra time creating them before you can get moving with the project.
New web-based software technology is being developed that creates IO-Link function blocks and integrates device data into a wide range of common PLC control systems in a matter of minutes. You can follow a step-by-step process in a web-browser dashboard and create a fully tested function block ready to use in your code.
You don’t even need to be experienced in IO-Link and there’s no need to start searching for parameters, indexes and data formats. You can download a library with all the software you need to install the function block as well as the full supporting documentation.
Read the full article in the February issue of DPA.
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