How to get the last changed value of a PI tag , in PI Data link.@@@@
You may try
I would recommend using PI DataLink's Compressed Data function with the Number of values constraint and an appropriate filter expression. Please see the screenshot below for the expressions that I used to retrieve the value of a tag before it last changed and its value after it last changed:
Note, I only specified the End time (highlighted in light blue) to show a range of compressed events for the tag to demonstrate the filter expressions... you don't need the end time to find the last changed value.
Retrieving data ...