Easy Chart Tag History Help

Ignition
1

Hello,

I was hoping for some help with Easy Chart component to visualize tag history. I am using version 7.9.16. I use a chart like below, two colored lines are temperatures from RTD, the black line is a set point. These are all configured to store tag history. This doesn’t happen consistently, but frequently the set point line is not displaying correctly. In the graph below, the set point changes from 70 to 60 to 30, but the graph displays it as a diagonal instead of steps. Is there something I can change about tag history parameters or chart properties that will help with this? Is it possible its because a SP doesn’t change for days at a time, and I have tag history set to “unlimited time between records” that the chart is interpreting long periods without change as interpolation and is connecting the dots that way?

Screen Shot 2022-03-02 at 5.27.10 PM
Screen Shot 2022-03-02 at 5.27.10 PM1590×916 179 KB

2

Edit the Set Point pen in the Easy Chart Customizer, and set the Style to Digital, it should then show the steps.

3

Thank you, that worked great and was super simple. For some reason I assumed digital was only for visualizing boolean type tags but that makes a lot of sense.

4

Is that tag specifically a Double or Float tag?

If so, you would want to check the Tag History props on the tag and make sure the “Deadband Style” property is set to “Discrete”.

Double/Float tags that have the default “Auto” value for the “Deadband Style” will interpolate their data on trends like the Easy Chart. If instead the property is set to “Discrete” then it will display as the step-like trend you are desiring and avoid interpolation.