IEC 60870-5-104

The Zeus IEC104 module targets power telecontrol, energy gateway, and station data acquisition scenarios. The built-in path covers the common master-side workflow: STARTDT, general interrogation, single commands, and normalized, scaled, and short-float measured/setpoint values. The link layer implements IEC 60870-5-104 t1/t2/t3 timers and the k/w window: t1 waits for I/U acknowledgements, t2 bounds S-format acknowledgements, and t3 sends TESTFR act after idle.

Install

dotnet add package Zeus.Communications
dotnet add package Zeus.Protocols.Iec104

IEC104 usually runs over TCP. For hardware-free testing, start with a virtual station:

var options = new Iec104Options { CommonAddress = 7 };
var memory = new Iec104StationMemory();
memory.SetSinglePoint(1, true);
memory.SetScaled(100, 253);
memory.SetShortFloat(200, 25.3);

await using var app = ZeusHost.Create(builder =>
{
    builder.AddVirtualChannel("iec-link", new Iec104SlaveResponder(options, memory));
    builder.AddIec104("station", "iec-link", options);
});

await app.StartAsync();
var station = app.Devices.Get<Iec104Device>("station");
var values = await station.InterrogateAsync();

For a real gateway, switch only the channel:

builder.AddTcpClient("iec-link", "192.168.1.20", 2404);
builder.AddIec104("station", "iec-link", new Iec104Options { CommonAddress = 7 });

Point Polling

builder.AddAcquisition(TimeSpan.FromMilliseconds(1000));
builder.AddIec104(
    "station",
    "iec-link",
    new Iec104Options { CommonAddress = 7 },
    points: map => map
        .SinglePoint("running", 1)
        .Scaled("temperature", 100, scale: 0.1)
        .ShortFloat("pressure", 200));

The acquisition loop runs general interrogation and publishes matching IOAs to the point table. A Scaled point with scale: 0.1 publishes wire value 253 as engineering value 25.3.

Write-Back

builder.AddIec104(
    "station",
    "iec-link",
    new Iec104Options { CommonAddress = 7 },
    points: map => map
        .SinglePoint("remoteSwitch", 1).Writable("remoteSwitch")
        .Scaled("setpoint", 100, scale: 0.1).Writable("setpoint"));

await app.Points.WriteAsync("remoteSwitch", true);
await app.Points.WriteAsync("setpoint", 18.6);

SinglePoint uses a single command. Normalized, Scaled, and ShortFloat use matching setpoint commands. Points with scale are converted back to wire values before write-back.

JSON Configuration

{
  "channels": [
    {
      "name": "iec-link",
      "type": "tcp",
      "options": {
        "host": "192.168.1.20",
        "port": 2404
      }
    }
  ],
  "devices": [
    {
      "name": "station",
      "channel": "iec-link",
      "type": "iec104",
      "options": {
        "commonAddress": 7,
        "t1Milliseconds": 15000,
        "t2Milliseconds": 10000,
        "t3Milliseconds": 20000,
        "maxUnacknowledgedIFrames": 12,
        "acknowledgeWindow": 8
      },
      "points": [
        {
          "name": "running",
          "options": {
            "address": 1,
            "dataType": "single-point"
          }
        },
        {
          "name": "temperature",
          "options": {
            "address": 100,
            "dataType": "scaled",
            "scale": 0.1
          }
        },
        {
          "name": "pressure",
          "options": {
            "address": 200,
            "dataType": "short-float"
          }
        }
      ]
    }
  ]
}

Virtual station configuration:

{
  "name": "iec-link",
  "type": "virtual",
  "options": {
    "responder": "iec104",
    "commonAddress": 7
  }
}

Supported Types

Type	Direction	Zeus Type
M_SP_NA_1 / C_SC_NA_1	Poll / write	SinglePoint
M_ME_NA_1 / C_SE_NA_1	Poll / write	Normalized
M_ME_NB_1 / C_SE_NB_1	Poll / write	Scaled
M_ME_NC_1 / C_SE_NC_1	Poll / write	ShortFloat

Link-layer timers default to the annex values: t1=15s, t2=10s, t3=20s, k=12, w=8. Set t3Milliseconds to 0 to disable TESTFR when using a virtual station. A t1 timeout resets sequence numbers and requires STARTDT again.

For timestamped ASDUs, double commands, file transfer, or balanced-mode extensions, inspect the actual peer frames with channel tracing before extending Zeus.Protocols.Iec104.