Unsolicited Response settings

DNP3 is an event-driven protocol. Instead of the master continuously polling the slaves for changes, the slaves monitor any data changes, such as bits toggling and analog value changing outside of a deadband. They then report the updates to the master as timestamped events in one of the following ways:
  • Unsolicited response: Sends the updates as a write message initiated by the slave.
  • In response to the poll from the master: Data objects in the slave are configured to Class 1, Class 2, and Class 3, typically based on priority. The class of the highest priority is polled more often.
  • DNP3 slave has the following behavior changes starting from firmware revision 23.012:
    • If a configured variable is assigned to multiple classes, the DNP3 slave generates separate events for each class. For example, if a binary input variable belongs to Class 1, Class 2, and Class 3, a single state change produces three events, one for each class.
    • The DNP3 slave stores and reports events in separate buffers according to their assigned DNP3 class. This ensures that unsolicited event reporting is class-specific and maintains the integrity of class-based event prioritization.
    Example
    If the following events occur:
    • Class 1 event: T1
    • Class 2 event: T2
    • Class 2 event: T3
    • Class 1 Event: T4
    • Class 3 event: T5
    • Class 2 event: T6
    Starting from firmware revision 23.012, the DNP3 slave stores and reports them by class:
    • Class 1 events: T1 and T4
    • Class 2 events: T2, T3, and T6
    • Class 3 event: T5
    For firmware revisions 23.011 and earlier, all events are stored in a single buffer without class separation: T1, T2, T3, T4, T5, and T6.
DNP3 Slave - Unsolicited Response settings
Setting
Description
Channel for unsolicited response
Determines the communication channel over which unsolicited responses are sent.
Only channels that are configured for DNP3 protocol are available in the list. Options are:
  • Embedded Serial Port
  • Ethernet Port
  • UPM Serial Port
    (available when the 2080-SERIALISOL plug-in module is added)
Restore events after a power cycle
Determines whether to restore the event records after a power cycle. By default, the controller deletes any DNP3 event records in the memory when power is cycled.
Send the initial unsolicited null response on restart
Determines whether the controller sends the unsolicited null response with the RESTART IIN bit on startup.
Enable unsolicited response on startup
Determines the way that the controller sends the unsolicited response.
  • Clear the checkbox if you do not want the controller to send an unsolicited response to the DNP3 master until it receives an Unsolicited Enable command from the master.
  • Select the checkbox to send the unsolicited response unconditionally. The checkbox is available when a Class is enabled.
Number of retries
Specifies the number of message resend attempts. Options are:
  • 0
     turns off retries
  • 65535
     denotes indefinite retries
For unsolicited response only.
Unsolicited response for Class 1
Turns unsolicited response for Class 1 on or off. By default, it is turned off.
Unsolicited response for Class 2
Turns unsolicited response for Class 2 on or off. By default, it is turned off.
Unsolicited response for Class 3
Turns unsolicited response for Class 3 on or off. By default, it is turned off.
Number of events
Specifies:
  • For classes with unsolicited response turned on: The maximum number of events to capture before triggering an unsolicited response. The value is from 0 through 10000. if you enter
    0
    , the event will not be generated.
  • For classes with unsolicited response turned off: The maximum number of class events to be logged. Any additional events occurring before a master poll for that class are lost.
Hold time after events
Specifies the maximum duration, in seconds, for a group of events to be held before sending an unsolicited response.
The box is available when unsolicited response for the class is turned on.
The value is from 0 through 65535.
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