You have different options but the one that may work for you is to include the previous different value on your Notification by using an output expression on your Event frame analysis.
Note: This Output expression feature only available on version 2017R2 (22.214.171.12452) or later
Here is an example I reproduced on my system with a similar case as yours:
In my case I have the event frame analysis triggers when my input attribute 'Status OPC' is not equal to "0 | Good". I define then an output expression associated to an Output attribute "Llama_Output2" that will get the Previous value of the input attribute using PrevVal() function.
You can then configure your Notification format to get the previous value recorded on "Llama_Output2" as well as the current value on the same email as soon as the Event frame analysis is triggered.
I hope this information is useful!
Thank you for your help Diego. I’d like to try adding the output expression like you described but I can’t seem to find the place to do this. I’m running 2017 R2 but don’t see an “Add” button. I have 2 options at the bottom of the analysis frame, “Add a new variable” and “Add a new start trigger”. Any idea how to add an output attribute from here?
Sorry for the delay. If it still helps you, it seems you do not have the last updated version of 2017R2 where this function was introduced. Here is the full name of the install kit you may download from Tech support website:
- PI AF Services and PI Web API 2017 R2 - Update 1 Install Kit
Also, the newest version of AF/Analysis 2018 has the functionality.