I/A Series R2 station idle time is too low. How do I correct it?


My I/A Series R2 UNC station idle time is about 5%.  How do I improve it?

Product Line

TAC I/A Series


I/A Series R2 UNC (410, 500, 510, 520, 600, 610)


Station processing was not optimized to maximize the processor idle time.


  1. Run the System Spy by entering http://:3011/system/spy into browser and specifying the IPAddress of the UNC.
  2. When the display comes up, scroll to the bottom of the page and click the 'Reset Counters' link.
  3. Wait 45 seconds for the counters to be updated before clicking the link to return to the spy statistics screen.
  4. Note the displayed idle time.  If it is above 20% no further action is required.  If below 20%, continue with the steps below to optimize the timing.  Please be aware that these steps are only suggestions.
  5. Increase the cycleTime on the UIEngine Service properties--config screen from the default of 500 ms to a value in the range of 2500 to 5000 ms.  This value controls the update frequency of point values on the WorkplacePro and Graphic screens, both locally and via web browser access.  This timing affects the update rate for points on graphic screens.  Remember that regardless of how fast the update rate is specified, updates will only occur when new values are received from point or device.
  6. All LOG objects that have a log interval of greater than 2 minutes should be configured with an execution frequency of "minutely".  In addition, any objects being logged or used in calculations for a logged value, if not being used for other purposes, should be configured for "minutely" execution.
  7. Any objects that are involved with passing or using low priority values such as outdoor air temperature/humidify (and using/passing any other low priority value objects) should be assigned an execution frequency of "slower".
  8. Verify that there are no "custom program" objects that could be replaced with standard objects or combinations of standard objects.  In any case where the station contains more than the recommended maximum number of program objects, an effort should be made to reduce the number of program objects by as much as possible.
  9. Repeat steps 2, 3 & 4, above.  If the idle time is still less than 20% continue with the steps below to optimize the execution frequency time intervals.
  10. Review status screen for the Control Engine service noting the following four sets of corresponding values.
  11.  If any of the four "Overruns" counters shows a significant number of overruns, note this fact for use in step 15 below.
  12. Compare each of the four "...AverageExecuteTime" values to the corresponding execution frequency value (on config tab) and if the value exceeds 50% of the configured execution frequency note this for use in the step 14.
  13. Open the Config tab of the ControlEngineService Properties screen.
  14. Referring to the values noted in step 12, the "normal" execution frequency needs to be set to a time value that is at least double the value of the "normalAverageExecuteTime".  If this time value exceeds the setting for the "slower" execution frequency, the "slower" execution frequency should be increased so that it is at least 50% greater than the "normal" execution frequency.  Adjust the fastest and faster executionFrequencies proportionally to the change made in the normal execution frequency.  For example if the "normal" execution frequency was increased from 2 to 5 seconds, the "fastest" execution timer would be increased to 1.3 sec and the "faster" execution timer increased to 3 seconds. 
  15. If any corresponding "overruns" counter shows a significant percent of overruns, as compared to the corresponding cycle counter, and you did not already increase the corresponding execution frequency to at least double its original setting, increase it appropriately.  Refer to step 14, above, regarding the suggested changes for the other execution frequencies.
  16. Apply the settings, save the station and restart it to force the changes to become effective.