Associated with: DNP3 SCADAPack E outstations and DNP3 SCADAPack Remote E outstations; DNP3 SCADAPack points and pulse actions
Security permission required to access this pick action: Off/On Scan
NOTE: The ability to place points and outstations Off Scan is disabled on most systems by default. (Its permission is typically denied on a per server basis.)
WARNINGUNEXPECTED BEHAVIOR OF APPLICATION
Use the Off Scan pick action on an outstation with care—always check an outstation’s current activity before deciding whether to use this action.
To check whether an outstation is currently processing a request, look at its entry in the Outstations List’s Current Request column. You can also check an outstation’s current activity via, for example, the Events List or the outstation’s Status display.
Depending on the system configuration, it may be possible to place individual points, or outstations and their dependants (such as points and pulse actions) ‘Off Scan’.
When an item is Off Scan:
- If the Off Scan item is a point or pulse action on an outstation that is still active, that and any other Off Scan items will not report data to any of their DNP3 masters (including ClearSCADA)
- If the Off Scan item is an outstation, the driver will send Data Link Status polls to that device to check that it is still there, but will not scan the device for other data
- Any changes to the item’s configuration can still be downloaded to the outstation (even if the outstation itself is Off Scan)
- Files can still be transferred to and from the outstation, including files for any Off Scan items
- While Off Scan, the item’s functionality is much reduced. As such, only a limited subset of pick actions remain available from the item’s context sensitive menu
- The item’s foreground color changes on various ClearSCADA displays to indicate that the item is Off Scan.
An Off Scan item differs from an item that is not In Service. An item that is not In Service is not scanned at all and is effectively ignored by ClearSCADA.
To place an individual point or pulse action Off Scan, select the Off Scan pick action from that item’s context sensitive menu.
To place an outstation Off Scan, select the outstation’s Off Scan pick action to display the Off Scan window.
Select the window’s Include Points check box if each of the outstation’s dependants, such as points and pulse actions, are also to be placed Off Scan. No events are generated, or data logged, for any points or pulse actions while they are Off Scan.
Ensure the check box is clear if the outstation’s dependants are to remain On Scan. Although the outstation does not report any data to ClearSCADA while it remains Off Scan, the points and pulse actions will remain ‘live’. As such, the outstation may continue to generate events and/or log data for any On Scan items. Such data will be stored locally at the outstation and be retrieved by ClearSCADA when the outstation is placed back On Scan.
With PSTN or ‘On Demand’ outstations and points and pulse actions on such outstations, the Off Scan window may display a Queue check box. Use the check box to indicate whether ClearSCADA is to perform the request immediately, or queue the request if ClearSCADA is not currently in communications with the outstation (see Queue Check Box in the ClearSCADA Guide to Drivers).
The entry that is logged in the Events List when the Off Scan pick action is triggered on an outstation indicates whether the Off Scan request includes the outstation’s points. Additionally, each item’s Scanning Scanning status attribute indicates whether that item is currently On or Off Scan.
Use the On Scan pick action to return an Off Scan item back to its fully functioning ‘On Scan’ state.