Scan class health points

To configure a health point for a scan class, set its location4 attribute to the scan class. To monitor the point count for unsolicited points, set location4 to 0. Unless otherwise stated in the description of the point, a scan class health point receives the system digital state NO RESULT if there are no interface points loaded for the scan class.

Use the extended descriptor (exdesc) point attribute keyword to specify what type of information to gather. Use square brackets around the keyword.

Scan class health points include the following types:

• Scan class point count

  Keyword: [UI_SCPOINTCOUNT]

  Contains the number of points loaded by the interface for a specified scan class. If location4 is 0, the point monitors the point count for unsolicited points. The scan class point count returns 0 when there are no points for the scan class.

• Scan class I/O rate

  Keyword: [UI_SCIORATE]

  Tracks the number of events sent to Data Archive before exception processing for the given scan class. If the scan class update executed successfully, the point contains a value between zero and the scan class point count inclusive. If location4 is 0, the point monitors the I/O rate for unsolicited points. If the point stops updating in Data Archive, an error has occurred and the points for that scan class are no longer receiving new data. The point is updated after the completion of each scan.

• Scan class bad value rate

  Keyword: [UI_SCBVRATE]

  Calculates all the bad values being sent to Data Archive before exception processing from the device with a status of anything other than good. This point can be defined for each scan class and is used for all input points in that particular scan class. Updated at the completion of associated scan class. If location4 is 0, the point monitors the bad value for unsolicited points.

• Scan class scans skipped

  Keyword: [UI_SCSKIPPED]

  The total number of scans skipped since the last reporting period. This point tracks the number of scans that were not performed before the scan time elapsed and the next scheduled scan was executed. The value of this point is event-driven and updates each time a scan is skipped. If location4 is 0, the point monitors the total scans skipped for all of the scan classes. The value of the point is set to zero at the beginning of each reporting period.

• Scan class scan count

  Keyword: [UI_SCSCANCOUNT]

  The number of scans performed by the interface since the last reporting period. The value of this point is incremented after the completion of every scan. If location4 is 0, the point monitors the total number of scans for all of the scan classes. The value of the point is set to zero at the beginning of each reporting period.

• Scan class scan time

  Keyword: [UI_SCINSCANTIME]

  The total amount of elapsed time in milliseconds required for the interface to read data from the foreign device, populate the input points, and send the data to Data Archive. The value for this point is updated after each completed scan.

• Scan class input device scan time

  Keyword: [UI_SCINDEVSCANTIME]

  The time in milliseconds required to read data from the foreign device and populate the input points. This value is a subset of the total scan class scan time and can be used to determine the percentage of time spent communicating to the foreign system compared with the percentage of time spent communicating with Data Archive.

  If the scan class scans skipped point value is increasing, consult the scan class scan time and scan class input device scan time points to identify where the delay is occurring: the data source communication, the PI System communication, or elsewhere.