Reference · built on requestConnectorIndustrial & building protocols

DNP3

Binary, analog, and counter points, class events, and controls from DNP3 outstations over serial or TCP/IP.

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About

DNP3 is the Distributed Network Protocol, published by the DNP Users Group and adopted as IEEE Std 1815. It carries data acquisition and control between a master in a control center and outstations in the field over serial links or TCP/IP. An outstation holds arrays of binary inputs, analog inputs, counters, control outputs, and analog outputs, each addressed by a zero-based point index. Values travel as objects identified by group and variation numbers, with a flag octet that marks a point online, restarted, forced, or over range.

Through Fibric, a master of its own polls the outstations you name for class events and static data, or receives unsolicited responses, and hands each change to an operator. A control or setpoint is proposed for your approval and sent once as a select-before-operate or direct-operate sequence.

This is a reference listing. It documents what Fibric would read from DNP3 and what it could propose, based on the vendor's published interfaces. Fibric builds it under a managed deployment when you request it; selecting it here installs nothing.

Inputs

  • Static binary input, analog input, and counter values, read by point index with a flag octet for online, restart, forced, and over-range states
  • Class 1, 2, and 3 events with or without time stamps, polled by class or reported as unsolicited responses
  • Analog change events past a configured deadband, in the integer and floating-point variations of object group 32
  • Counter values for energy or fluid volume totals that roll over to zero at their maximum
  • Static present values from group 30 and its peers, read occasionally as an integrity check between event polls
  • Configuration files and logged or historical data transferred from the outstation
  • Link addresses and restart indications from the frame header and flag bits, across the 65520 individual addresses a link allows

Proposed actions

  • Target capability: propose a trip, close, raise, or lower control on a control output point, sent as a select-before-operate or direct-operate sequence
  • Target capability: propose an analog output setpoint, such as a regulated pressure or a desired voltage level
  • Target capability: propose a freeze of counter accumulators before the master reads them
  • Target capability: propose setting the outstation's time and date from the master

Proposed actions are target capabilities. Every action runs propose-first and needs a validated deployment and the appropriate permissions.

What you can build

  • Watch feeder events without a polling lag

    Outstations report Class 1 events as unsolicited responses. The operator groups the burst of binary changes behind one fault, names the feeder, and posts a single notice instead of hundreds.

    With Alarm Flood, Alarm Triage

  • Hold generation output during a grid event

    When a curtailment request arrives, the operator proposes analog output setpoints for the DER outstations you name. You approve. Each setpoint goes once, and the receipt records the point index and value.

    With Event Response, Export Limit

  • Test a standby generator on schedule

    The operator proposes the start control, watches the analog inputs for voltage and current, and records the run against the test calendar.

    With Generator Test

  • Spot a stale outstation

    The flag octet marks a point offline or communications lost with a downstream source. The operator lists outstations whose flags changed or whose polls time out, so a person can send a crew.

    With Sensor Health, Data Freshness

Requirements

  • Serial (RS-232 or RS-485) or TCP/IP reach to each outstation, and a unique link address for the master
  • The outstation's point list: which indexes hold which binary, analog, counter, and control points, and their assigned event classes
  • Outstations that support unsolicited responses, if you want changes without waiting on a polling cycle
  • For controls, outstations at an implementation level that includes select-before-operate or direct-operate on the points you name
Authentication
DNP3 has no login of its own, so access rests on link addresses and network reach; IEEE 1815 Secure Authentication adds application-layer authentication of critical operations with role-based users, and TLS is supported on IP networks.

Limits

  • The specification volumes are sold by the DNP Users Group, and member-only documents such as the Device Profile Guide are not public
  • A link frame carries at most 250 data octets and application fragments run 2048 to 4096 bytes, so bulk reads are paced by outstation buffers
  • Secure Authentication authenticates messages but does not encrypt them; confidentiality on IP networks comes from TLS, and serial links stay in the clear
  • Unsolicited reporting must stay infrequent on shared media, and DNP3 leaves the collision-avoidance method to the implementer

Access and pricing

Reference listing. Fibric builds the connector under a managed deployment when you request it. Your quote covers the build, capabilities, usage, and support.

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Questions and answers

Does DNP3 run over TCP/IP?
Yes. DNP3 link-layer frames can be embedded in TCP/IP packets, and many products transport DNP3 that way, alongside serial links such as RS-232 and RS-485 and multi-drop radio or telephone circuits.
How does a master learn about a change without polling?
An outstation that supports unsolicited responses transmits a response on its own when a change occurs. Otherwise the master polls for Class 1, 2, or 3 events, and reads static data only occasionally as an integrity check.
Is DNP3 encrypted?
Not by the base protocol. IEEE 1815 Secure Authentication authenticates critical operations and users at the application layer, on serial and IP networks alike, but does not encrypt. TLS is supported for DNP3 on IP networks.
Ask about DNP3

Ask about the capabilities and requirements in this listing.

For project-specific requirements, contact Fibric.

This connector listing is developed, published, and supported by Fibric. It describes integration with DNP3 through published interfaces. Third-party names and logos identify the systems an integration connects to; they are the property of their respective owners, who are not affiliated with Fibric and do not sponsor or endorse this listing. Trademark policy