Report on setpoint deviations
The average deviation from a setpoint can be a good performance metric for reporting. Extracting the average process deviation for a defined period follows a simple two-step process.
Create a tag that specifies the absolute value of the difference between the value and the setpoint.
Navigating to the desired time period and then opening the statistics table, the average value of the deviation tag shows the average deviation between the target value and the process value. Checking this value for multiple time periods, we can easily compare the performance.
Using calculations on search results rather than the statistics table
Any workflow where we use the statistics table to calculate metrics for a custom period, we could also apply in bulk to multiple periods in a two-step process:
Searching for the periods for which we want to extract the metrics
Calculs sur les résultats de recherche
Add the calculation of the process metrics as calculation on search results. The values will be calculated for all periods at once, and can easily be exported to Excel.
The search and its calculations can be saved, so the analysis can be repeated at any time by simply loading the search.
Report as a moving average tag rather than a single value
When we use the statistics table to calculate metrics for a custom period, we can often also create a tag giving us the average over the last hours, using the average aggregation in the tag builder. The resulting tag can be displayed live and can be used for monitoring. This is only applicable when the value to be reported on is continuous (i.e., there are no periods for which the value needs to be filtered out).