# DNP3

> Read and control DNP3 outstations in power, water and wastewater utilities and industrial substations, with events, quality flags and time stamps.

DNP3 is the common SCADA protocol of electric and water utilities in many countries. PLCGateway is a DNP3 master over TCP: it runs an integrity poll after connecting and periodically, collects events with class polls or unsolicited responses and synchronises the time of the outstation when it asks.

Binary and double-bit inputs, analog inputs, counters and output states become tags with DNP3 flags and event time; control relay output blocks (latch, pulse, trip, close) and analog outputs are sent with direct operate or select-before-operate.

- **Driver id:** `dnp3`
- **Connection:** DNP3 over TCP · port 20000
- **Address browsing:** addresses are typed or imported
- **Writing:** yes
- **Included in:** PLCGateway Connect, PLCGateway SCADA, PLCGateway Embedded

## What PLCGateway reads and writes

- Binary and double-bit inputs with events
- Analog inputs in 16 / 32-bit, float and double
- Counters and frozen counters
- Binary and analog output status
- CROB latch, pulse, trip and close; analog output commands
- Flags (online, restart, communication lost, forced, over range) and event times

## Address examples

| Address | Meaning |
|---|---|
| `bi:0` | Binary input 0 |
| `dbi:2` | Double-bit input |
| `ai:5` | Analog input 5 |
| `ctr:2 · fctr:2` | Counter / frozen counter |
| `bo:1 · bo:3.trip` | Binary output with latch / trip command |
| `ao:0` | Analog output |

## Controllers and devices

- [Protection relays, IEDs and RTUs](https://plcgateway.com/controllers/protection-relays.md)

## Connect in a few steps

1. Agree on the outstation address, the master address and the point list with the device owner.
2. Add a DNP3 device with IP address, port 20000 and the addresses; choose event polling or unsolicited responses.
3. Create the points as tags or import them from CSV.
4. Use the values in screens, alarms, energy management and reports.

## Questions and answers

### Is DNP3 serial supported?

PLCGateway supports DNP3 over TCP/IP. Serial outstations can be reached through a terminal server that forwards the serial line over TCP.

### Are select-before-operate controls supported?

Yes, every device can use direct operate or select-before-operate; the status code of the outstation is reported, for example local control or not supported.

### Is DNP3 Secure Authentication supported?

No. Use a protected network or VPN for DNP3 connections.

## Related protocols

- [IEC 60870-5-104](https://plcgateway.com/protocols/iec-60870-5-104.md)
- [IEC 61850 MMS](https://plcgateway.com/protocols/iec-61850.md)
- [Modbus TCP / RTU](https://plcgateway.com/protocols/modbus.md)
- [All protocols](https://plcgateway.com/protocols.md)

_Product and model names are trademarks of their owners. They are named only to show which equipment the drivers communicate with; PLCGateway is not affiliated with these companies._

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Source: https://plcgateway.com/protocols/dnp3