IEC 60870-5-104

IEC 60870-5-104 (IEC 104) is the TCP/IP telecontrol protocol of power system SCADA. A controlling station (the control centre) talks to controlled stations (substations, RTUs, generation and storage assets) on TCP port 2404. Each station has a common address, and each data point an information object address. The control centre runs interrogations, receives spontaneous events, and sends commands, often with select-before-operate.

Where you meet it

• Links between grid control centres and substations
• Solar parks, wind farms and battery storage connected to a grid operator
• RTUs and gateways in distribution and transmission networks

Quickstart

From the command line

Download iec104ctl from GitHub Releases. No station at hand? Start a simulated one:

iec104ctl server start

and talk to it from another terminal:

# What does this station hold? (general interrogation)
iec104ctl client interrogate --ip 127.0.0.1 --ca 1

# Watch events and measured values as they arrive, until Ctrl-C
iec104ctl client monitor --ip 127.0.0.1 --interrogate

# Operate a disconnector with select-before-operate
iec104ctl client command --ip 127.0.0.1 --type double --ioa 5001 --value off --mode sbo

# Is the link alive, and how fast?
iec104ctl client ping --ip 127.0.0.1

From Go

go get github.com/otfabric/go-iec104

Connect, interrogate and synchronize the clock:

package main

import (
  "context"
  "fmt"
  "log"
  "time"

  "github.com/otfabric/go-iec104/asdu"
  "github.com/otfabric/go-iec104/client"
)

func main() {
  ctx := context.Background()

  // Dial connects and sends STARTDT. Every ASDU the station sends
  // reaches the handler, in order.
  c, err := client.Dial(ctx, "10.0.0.5:2404",
    client.WithReconnect(client.Reconnect{}),
    client.WithHandler(client.HandlerFunc(func(a *asdu.ASDU) {
      for _, obj := range a.Objects {
        if m, ok := obj.(asdu.MeasuredFloat); ok {
          fmt.Printf("%s ioa=%d value=%g quality=%s\n", a.Cause, m.IOA, m.Value, m.Quality)
        }
      }
    })))
  if err != nil {
    log.Fatal(err)
  }
  defer c.Close()

  // General interrogation of station 1.
  data, err := c.Interrogate(ctx, 1, asdu.QOIStation)
  if err != nil {
    log.Fatal(err)
  }
  fmt.Printf("interrogation returned %d ASDUs\n", len(data))

  if err := c.ClockSync(ctx, 1, time.Now()); err != nil {
    log.Fatal(err)
  }
}

What go-iec104 supports

Interoperability

iec104-interop tests go-iec104 against MZ Automation lib60870-C, OpenMUC j60870 and wendy512/iec104, as both client and server. It has not been tested against certified test equipment.