Historical Data Resolution

Ignition
1

I’m collecting historical data for a group of tags with a scanclass rate of 10 seconds. I’d like to keep this resolution for data storage, but I have a user who would like to export the data they see in an EasyChart so that there is only one data point per minute.

I’ve played around with the tag history resolution on the chart, and I can get close, but it always seems like there are duplicate data points in the exported data. For instance, attached is an image of a 10-minute selection on the graph with a tag history resolution of dateDiff({Root Container.Easy Chart.startDate},{Root Container.Easy Chart.endDate},“minute”)=10. I’m getting what I want (one sample per second), but there are two data points per minute (with different values). What do these represent and is it possible to get just one value per minute?

2

In case anyone else comes across this issue, here’s my workaround for now.

I had to create a separate button with a script that used the system.tag.queryTagHistory() method to get the data I wanted, using intervalMinutes=1. I then exported the data using system.dataset.exportExcel().

Not as clean as the built-in “save” button on the chart, but it works. If anyone figures out how to do it using the chart, please post.