Hello, First time posting so please let me know if I am doing anything wrong.
I am trying to pull the history of a tag with intermittent data. There will be several seconds of readings; however, most of the time the reading is 0.
When I use the queryTagHistory function it will not include these spikes if I set the intervalMinutes too high (above 0.4). Does the function not sample all of the datapoints in the range to determine the maximum as the interval increases?
Example:
Returns the data correctly but with over 1,000,000 rows
system.tag.queryTagHistory(paths=tagPaths, columnNames = tagTitles, startDate=startTime, endDate=endTime, aggregationMode=“Maximum”, intervalMinutes=0.4, returnFormat=‘Wide’)
Returns the data incorrectly. All rows returning 0
system.tag.queryTagHistory(paths=tagPaths, columnNames = tagTitles, startDate=startTime, endDate=endTime, aggregationMode=“Maximum”, intervalMinutes=10, returnFormat=‘Wide’)
It looks strange to me that you are seeing all the rows return 0 at intervalMinutes=10. Given that you have a maximum that is higher than 0 with a smaller interval, I would expect that you would still see a value higher than 0 at a larger interval. What is the expected data that you would want to see at intervalMinutes=10 and what is the data that you are getting at intervalMinutes=0.4? Could you share a screenshot of the results from both case? What are the startDate and endDates that you are using for both case?
Thanks for replying to this. I was able to go through Ignition Help and it was an issue with how the data was being saved in the historian, there were multiple entries for the same history event which was causing the function to behave strange.
There is some cleanup for the previous data in the historian to be done; however, it appears that this is not occurring for new data now which is good.