DNP3

Connection Settings

Notes

• Source Address and Destination Address: These addresses are assigned to the computers and should be the same across all settings, because of this the settings in Ignition and the settings in the device are the opposite of each other. For example, if the device is configured with an address of 4 and Ignition has an address of 3: 
  • the settings in Ignition should have the Source Address set to 3 and the Destination Address set to 4.
  • the settings in the Device should have the Source Address set to 4 and the Destination Address set to 3.
• Unsolicited messages enabled property: setting this property to True (checking the box) allows the outstation to send unsolicited messages to Ignition. This means that Ignition will connect to the outstation, but not request any data from it.  Ignition waits for the outstation to send data.   Not all devices support this option; those that do need to be configured to use it. Please refer to your device's documentation for more information. 

Internal Indicators

Each response received from a connected outstation will contain an Internal Indication (IIN) bit field.  This field indicates certain states or error conditions in the outstation. IINs are mapped to read-only points, indicating the following:

• Broadcast message received (Broadcast)
• Additional Class 1, 2, or 3 event data is available (Class 1 Events, Class 2 Events, Class 3 Events)
• Time synchronization required in the outstation (Need Time)
• Some output points are in local mode (Local Control)
• An abnormal condition exists (Device Trouble)
• The outstation device has restarted (Device Restart)
• Function code not implemented (No Func Code Support)
• Object Unknown (Object Unknown)
• Request parameter error (Parameter Error)
• Outstation event buffer overflow (Event Buffer Overflow)
• An operation is already executing (Already Executing)
• Configuration corrupt (Config Corrupt)

Terminology

• unsolicited response: An Application Layer message from an outstation to a master for which no explicit request was received.  The request is implied by the act of a master enabling unsolicited reporting of various points within an outstation.
• integrity poll: Requests all event data, followed by the static data of all points assigned to one of the four classes (static Class 0 or event Class 1, 2, or 3).
• DNP3TIME: Univeral Coordinated Time (UTC) time expressed as the number of milliseconds since the start of January 1, 1970.  The effective date for using the UTC time base is January 1, 2008.  Prior to this, DNP3 did not require a specific time reference.

Aliased Points

Aliased points allow the user to assign meaningful names and descriptions to DNP3 points. They are also useful for addressing any points that were not returned by the initial integrity-poll on connection.

Buffered Events

Buffered events can be enabled by setting the Queue Size property on the corresponding Tag Group to a number greater than 1. (See Queue Size on the Tag Groups page.) The number represents the number of buffer events that will be handled by the driver. The queue always keeps the most recent events, dropping older events. For example, if Queue Size were set to 20, and 30 value changes occur on the device while disconnected, then the 10 oldest events would be ignored by the driver.

After recovering from a disconnect, the driver will playback missed events from the driver, and update the value on the corresponding Ignition Tags by cycling through each event quickly, from oldest event in the buffer to the most recent. This value change will trigger value changes in certain systems. Specifically:

• alarms events (recent evens as well as alarm journal records)
• Tag History records (when the History Sample Mode is set to "On Change")
• Tag Events Scripts 

Once finished cycling through the buffered values, the Tag will resume showing the live value. 

Support for this Feature

This Buffered Events feature can only be used by devices that support Sequence of Events (SoE), and have the option enabled for points Ignition is subscribed to. Note that the data type for SoE may differ from the data type that is received by normal subscription. This is generally due to a configuration on the Default Variation property in the device.