CODESYS 3.5 - PLC Programming With Structures - Lesson 9 - Why Use Structures With A HMI

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In this lesson we look at why structured data is such a powerful tool when working with HMIs, SCADA systems and visualization environments. This is only an introduction, and we will go deeper in the following lessons, but even this basic example shows how much simpler and cleaner your visualisation setup becomes when using structures.

We start with the project from the previous lesson, and a new visualization page containing a gauge object. This gauge has been preconfigured to accept a DUT_Analog structure. Instead of linking individual tags for raw value, scaled value, limits and status, the entire structure is passed in as one variable.

By selecting the gauge offline and opening the configuration window, we can see that its data source is simply pressure1.types.analog, which is the same structure we created earlier. Because the gauge is designed to read everything from that structure, no individual connections are needed.

Once online, adding scaling values into the structure immediately updates the gauge. Changing the raw value automatically updates the scaled value and the gauge reading, because the visualization is reading directly from the structured data that feeds the logic. Everything stays in sync without extra wiring, tag mapping or manual configuration.

This is one of the strongest reasons for using structures with HMIs and SCADA systems. Instead of tagging dozens of individual signals, you pass one structure and all relevant data becomes available in a predictable format. For equipment with many datapoints, such as pumps, motors, drives or analogue instruments, this saves huge amounts of engineering time and reduces the risk of tagging mistakes.

In the next lesson we will look behind the scenes and show exactly how to set up visualization elements that accept structured data.

#AlwaysLearning #Automation #Codesys #PLC #HMI