knx-go

This repository contains a collection of Go packages that provide the means to communicate with KNX networks.

Packages

Package	Description
knx	Abstractions to communicate with KNXnet/IP servers
knx/knxnet	KNXnet/IP protocol services
knx/dpt	Datapoint types
knx/cemi	CEMI-encoded frames
cmd/knxbridge	Tool to bridge KNX networks between a KNXnet/IP router and gateway

Installation

Simply run the following command.

$ go get -u github.com/bozzo/knx-go/...

Examples

KNXnet/IP Group Client

If you simply want to send and receive group communication, the GroupTunnel or GroupRouter might be sufficient to you.

package main

import (
	"log"
	"os"

	"github.com/bozzo/knx-go/knx"
	"github.com/bozzo/knx-go/knx/cemi"
	"github.com/bozzo/knx-go/knx/dpt"
	"github.com/bozzo/knx-go/knx/util"
)

func main() {
	// Setup logger for auxiliary logging. This enables us to see log messages from internal
	// routines.
	util.Logger = log.New(os.Stdout, "", log.LstdFlags)

	// Connect to the gateway.
	client, err := knx.NewGroupTunnel("10.0.0.7:3671", knx.DefaultTunnelConfig)
	if err != nil {
		log.Fatal(err)
	}

	// Close upon exiting. Even if the gateway closes the connection, we still have to clean up.
	defer client.Close()

	// Send 20.5°C to group 1/2/3.
	err = client.Send(knx.GroupEvent{
		Command:     knx.GroupWrite,
		Destination: cemi.NewGroupAddr3(1, 2, 3),
		Data:        dpt.DPT_9001(20.5).Pack(),
	})
	if err != nil {
		log.Fatal(err)
	}

	// Receive messages from the gateway. The inbound channel is closed with the connection.
	for msg := range client.Inbound() {
		var temp dpt.DPT_9001

		err := temp.Unpack(msg.Data)
		if err != nil {
			continue
		}

		util.Logger.Printf("%+v: %v", msg, temp)
	}
}

In case you want to access a KNXnet/IP router instead of a gateway, simply replace

client, err := knx.NewGroupTunnel("10.0.0.7:3671", knx.DefaultTunnelConfig)

with

client, err := knx.NewGroupRouter("224.0.23.12:3671", knx.DefaultRouterConfig)

KNXnet/IP CEMI Client

Use Tunnel or Router for finer control over the communication with a gateway or router.

KNX Bridge

The knxbridge tool (in package cmd/knxbridge) has multiple use cases.

Expose a KNX network behind a gateway at 10.0.0.2:3671 on the multicast group 224.0.23.12:3671. This allows routers and router clients to access the network.

$ knxbridge 10.0.0.2:3671 224.0.23.12:3671

Connect two KNX networks through gateways. In this example one gateway is at 10.0.0.2:3671, the other is at 10.0.0.3:3671.

$ knxbridge 10.0.0.2:3671 10.0.0.3:3671

Discover all KNXnet/IP Servers

The following example shows how to discover all routers/gateways on a network.

package main

import (
	"log"
	"os"
	"time"

	"github.com/kr/pretty"

	"github.com/bozzo/knx-go/knx"
	"github.com/bozzo/knx-go/knx/util"
)

func main() {
	// Setup logger for auxiliary logging. This enables us to see log messages from internal
	// routines.
	util.Logger = log.New(os.Stdout, "", log.LstdFlags)

	servers, err := knx.Discover("224.0.23.12:3671", time.Millisecond*750)
	if err != nil {
		log.Fatal(err)
	}

	util.Logger.Printf("%# v", pretty.Formatter(servers))
}