The Derived Point process maintains and updates all calculation points in the project. Calculation points typically take input from a device point and perform arithmetic, max capture, min capture, etc., and output this information to a point.
Data in the System Sentry Derived Points screen reports the derived point system use and performance.
Guidelines for reading the Derived Points screen include:
Check point requests per second (Point Req/Sec) and point responses per second (Point Resp/Sec)
Point Requests/Sec represents the number of calculation points the derived point manager updates.
Point Responses/Sec represents the number of point value updates the derived point manager receives. The derived point manager uses these point values to produce the calculations.
Check the derived point manager's CPU Usage. Excessive CPU usage and a large number of Point Req/Sec may indicate that too many calculation points are being updated too rapidly.
To reduce the load on the Derived Point Process:
Verify that device points are being reported OnChange rather than OnScan.
Reduce the number of calculation being performed.
Reduce the scan rate of the device points.
System Sentry screens list.