Accessing Tag History for Further Manipulation before Displaying

Ignition
1

Hi All,

I’m pretty new to Ignition. I have a requirement to access tag history where we store voltage values, calculate averages and show them as a chart. I know you can drag and drop historical tags onto a chart control and necessary bindings are created automatically. However, my requirement is NOT to display historical data as it is. I need to calculate averages and show them as a chart. The problem encountered is that I don’t know how to access history data within an expression of a query so that I can manipulate them. Am I doing it wrong? Any advice, directions would be highly appreciated.

P.S. Ignition version is 7.9

Best regards,
Shanaka

2

The tag historian has an aggregation mode of ‘Average’ and ‘Time Weighted Average’ (or something like those two). There’s a good chance you can use that to get what you need without having to do the calculations yourself.

1 Like
4

Thanks a lot for the reply. Yes, this might help. I’ll have a look.

Best regards.