I'm creating a spreadsheet to capture and analyze event data for a process in our plant. I can identify the start/end of the event by looking at the position of 3 valves. When all 3 valves are open, the event has started. I want to capture the timestamp of the event. My initial thought was to use the FindEQ function. Unfortunately, as far as I can tell you can only reference one tag. I was hoping there was a function such as:
FindNext('tag1'="OPEN" and 'tag2'="OPEN" and 'tag3'="OPEN", '01-Jan-14', '*')
Does any know of a way to get what I need using a minimal number of cells? I have a couple ideas but I'm hoping to find an alternative.
One would be to create a performance equation to identify the event and have DataLink reference the performance equation tag. I think that should theoretically be possible but our site has never setup the performance equation recalculator. Also, even if we had the recalculator working, will it calculate valves prior to its creation data? (I want data from at least the first of the year and maybe even 2013)
Another method that I've used in the past (with another vendor's historian that didn't have PI's PE selection) was to dump 1 day worth of raw data into a spreadsheet and write a macro that would search an event then record the timestamps on a separate sheet. The macro would then advance the raw data to next day and repeat until it reached the current date. This method works but it is very brute force and can take a while to run, I was hoping for something more succinct.
Any advice would be appreciated.
Chris