paroda

Performance Calculation by Event Trigger uses older value?

Discussion created by paroda on Jun 4, 2012
Latest reply on Jun 5, 2012 by Ahmad Fattahi

Hi,

 

I have several PE calculation which are triggered by Event of the input PI Tags. However, one common issue i found with all of them. please refer the graphic below.

 

4747.pecalc.png

 

The blue line is the input tag and the blue circle shows the archived events. there were more events inbetween but got omitted due to compression. The excmax attribute is set at 600s. The green and yellow ones represent two PE calcs based on this PI tag. They are (Tag * 0.98) and (Tag * 1.02).

 

Please observe the time shown by red 1. There is a blue circle showing an event for the input tag. Also green and yellow dots are also there showing the PE calcs. But their value corresponds to the blue circle on the left. Similarly on next instance (2), the calculated value again corresponds to the previous value of the input tag. On the next instance (3), the blue circle is missing as it got omitted on compression. The time gap between 2 & 3 is 10 min which corresponds to excmax value of the input tag. So on overall we get a kind of impression that the PE Calculated values are offset by 10 min, while in fact the PE calculation based on event trigger is taking the older value of the tag for calculation.

 

Maybe I have misinterpreted it. We just want to have PE calculated values to be in sync with the input PI Tag. How to fix it?

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