I’ll admit, I don’t always investigate every new feature that I read in a software’s release notes and many times I fail to utilize them for some time. Such is the case for tag extended properties in Logix Designer and View Designer.
Having used RSLogix 5000 since version seven, I have tried to keep with the new features at nearly every release and utilize them whenever possible. This week, I finally investigated this feature called tag “extended properties”.
Extended Tag Properties in Logix Designer:
In this screenshot, I am looking at my controller tags in which I have a tag called “TankLevel”.
On the right-side of the database, I can select “Properties” and expand the “Properties” window and select the “Thumbtack” to keep the window open.
Next, I will want to select the “Extended Properties” drop down and I picked all three properties (Engineering Unit, Max, Min) as shown.
I can now assign values to the Engineering Unit, Max and Min properties as they appear under the “Data” tab of the tag properties window.
Here, I am giving a digital tag called “Motor_RUN” a description of the motor’s equipment number.
Extended Tag Properties in View Designer
In View Designer, I can access the tag extended properties in the HMI screens. The extended property is accessed with the <tag name.@> syntax as shown below.
In these screenshots using numeric displays, we will display the “Max” and “Min” extended properties.
In the next couple of screenshots, we use the text display to display the engineering units for the “TankLevel” and tag description for “Motor_Run”.
At runtime, I can see the extended properties the same as any other dynamic value displayed on the HMI, and the difference is that a View Designer Modification and Download to the Panelview would not have to be made to make a simple change with a range or description. It can easily be modified online in the controller via the Logix Designer application.
Tag Extended properties are not only available in View Designer, but Factory Talk ME/SE latest versions as well.
Both the L7X and L8X lines of controllers have the ability to utilize tag extended properties in AOIs (Add-On instructions). In the L8X line of controllers, tag extended properties are available in alarm messaging as well.
This creates added flexibility and utilization when building a project, especially a new project from scratch.
Written by Brandon Cooper
Senior Controls Engineer and Freelance Writer