System Sentry Derived Points Screen

About this task

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.

guide:  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:

Procedure

  1. Verify that device points are being reported OnChange rather than OnScan.
  2. Reduce the number of calculation being performed.
  3. Reduce the scan rate of the device points.