Hi,
How can I extract a single data point from tag history and then display it. Or rather, I have an tag incrementing over time to keep track of my energy consumption. I want to use the tag history to display TODAYS energy consumption, without transfering more tags between ignition and my PLC.
Something like below (non script language).
energyConsumption(now) - energyConsumption(00:00)
Not sure if the is Vision or perspective, so here are links to relevant information:
https://docs.inductiveautomation.com/display/DOC81/Tag+History+Bindings+in+Vision
https://docs.inductiveautomation.com/display/DOC81/Tag+History+Bindings+in+Perspective
https://docs.inductiveautomation.com/display/DOC81/system.tag.queryTagHistory
The key is to use the correct aggregation. For instance if you just want the most recent value, then you can use the "Last Value" aggregation.
It's perspective, but using the tag history result in a table. I want only 1 value to display? In a numericalEntryField
I found a solution.
I took the tag history midnight(now) - now() and then made a transform Max-min