Every data packet that a DNP3 outstation sends to the DNP3 master (ClearSCADA) includes various DNP3 flags (internal indications). You can specify how ClearSCADA handles these flags.
To specify how ClearSCADA handles the Events Available IIN Bit, see Specify When ClearSCADA Performs Class Polls. The DNP3 standard recommends that events are recovered whenever an outstation indicates that they are available. However, you may want to limit this functionality on systems that have limited bandwidth or a high latency network.
To specify how ClearSCADA handles the IIN Bit(s) that are transmitted if a problem is detected at the outstation, see Specify the IIN Severity.
To specify how ClearSCADA handles the Respond to Need Time IIN, see Define Whether ClearSCADA Updates the Outstation Clock.
In addition to displaying alarms or events whenever an outstation’s IIN bits are set, each outstation’s Status display also indicates whether these DNP3 flags are set:
- Already Executing Alarm
- Configuration Corrupt Alarm
- Device Trouble Alarm
- Event Buffer Overflow Alarm
- IIN Status
- Protocol Alarm.
(For more information on Status displays, see DNP3 Specific Status Display Attributes, and the ClearSCADA Guide to ViewX and WebX Clients.)
A further DNP3 IIN bit, LOCAL_CONTROL, indicates whether any output points are in local operation mode. Whenever this bit is reported as being set, ClearSCADA logs a Points in Local Operation event in the Event Journal. Whenever a point is in local operation mode, any control commands sent from ClearSCADA might not execute successfully. See the outstation documentation for information on clearing the LOCAL_CONTROL IIN bit.