What I am attempting to do is retrieve the timestamp of the last time an attribute value was not equal to the current value.
A brief example:
Say I have a status tag which can be 0 or 1. Its recorded values in the database are for example:
Say the current time is 4am (t+4).
In my analysis, I can retrieve:
* Current Value = 1
* SecSinceChange = 3600 (seems to return seconds since the tag was last updated rather than a changed value)
I do not know how long ago the value was 0 or what time frame I should look at. In my scenario it could have been 2 months ago, or 2 minutes ago or anywhere in between!
Can anyone suggest how to retrieve the timestamp for the last time the value was equal to 0.