The Group Statistics display shows the statistics for the selected group. The number of transmits, receives, and errors are displayed for all items configured for the group.
To display a group’s statistics, select the group in the Tree Browser and then choose Stats Mode from the Display Mode menu.
The following fields and buttons are visible in the Group Properties Viewer in Stats Mode:
Transmits
Displays the number of reads and writes sent to the OPC server for all the items configured for the selected group.
Example:
- Number of items configured for the driver = 2
- Number of messages sent from Item1 = 30
- Number of messages sent from Item2 = 30
- Total number of messages sent = 60
- Transmits field displays: 60
Receives
Displays the total number of messages the group received from the OPC server, including both synchronous and asynchronous callbacks.
Errors
Displays the total number of errors that were sent from the OPC server and received by the selected group.
Errors occur when:
- You specify an invalid item ID or access path from the OPC server.
- The OPC server rejects a read or write request.
- The group is unable to establish an asynchronous connection with the OPC server.
For more information about the cause of the error, examine the Last Error field in the OPC item statistics.
Number of Items
Displays the total number of items configured for the selected group.
Actual Update Rate
Displays the actual update rate that the server uses to refresh this group’s data cache. This value may be different from the requested update rate if the requested rate is too small and the server cannot update the group at that frequency.
Pending Asynchronous Transactions
Displays the number of asynchronous read and write messages that are pending with the OPC server for the selected group. When the group uses synchronous I/O, the number of pending asynchronous message is always 0.
Troubleshooting
When clicked, this button displays the Troubleshooting help page.
Group Dialog Refresh Status
Displays the primary refresh rate and the refresh status for the selected group.
See Also
