📖HomeBack In some cases when ClearSCADA is configured to behave as a DNP3 slave device, although some triggered events have been set as Unsolicited Messages, no unsolicited messaged are ever sent.
This behavior is expected if the master station does not enable unsolicited messages in the slave device. This is sometimes the case with older master station SCADA systems or simple implementations of the DNP3 driver.
According to the DNP3 Technical Specification, the slave device is only allowed to send unsolicited messages with event data in them after the master station has enabled unsolicited messages for the appropriate data classes. Until the slave has had this message the only unsolicited message the slave will send is an empty unsolicited packet to announce itself to the master after start up.
The "Unsolicited Message Generation" field on the slave configuration within ClearSCADA controls whether or not the ClearSCADA DNP3 slave will send the empty unsolicited announcement packet on start-up and whether it will send unsolicited events to the master after being told it can by the master.
If the master never enables unsolicited reporting for the appropriate classes, the ClearSCADA DNP3 slave will never send unsolicited event data. If it did, this would break the DNP3 rules for slave devices.