KNX Binding

The openHAB KNX binding allows to connect to KNX Home Automation installations. Switching lights on and off, activating your roller shutters or changing room temperatures are only some examples.

To access your KNX bus you either need a gateway device which is connected to the KNX bus and allows computers to access the bus communication. This can be either an Ethernet (as a Router or a Tunne type) or a serial gateway. The KNX binding then can communicate directly with this gateway. Alternatively a PC running KNXD (free open source component sofware) can be put in between which then acts as a broker allowing multiple client to connect to the same gateway. Since the protocol is identical, the KNX binding can also communicate with it transparently.

Supported Things

The KNX binding supports two types of bridges, and one type of things to access the KNX bus. There is an ip bridge to connect to KNX IP Gateways, and a serial bridge for connection over a serial port to a host-attached gateway.

Binding Configuration

The binding itself does not require any special configuration.

Bridges

The following two bridge types are supported. Bridges don't have channels on their own.

IP Gateway

The IP Gateway is the most commonly used way to connect to the KNX bus. At its base, the ip bridge accepts the following configuration parameters:

Name Required Description Default value
type Yes The IP connection type for connecting to the KNX bus (TUNNEL or ROUTER) -
ipAddress for TUNNEL Network address of the KNX/IP gateway -
portNumber for TUNNEL Port number of the KNX/IP gateway 3671
localIp No Network address of the local host to be used to set up the connection to the KNX/IP gateway the system-wide configured primary interface address
localSourceAddr No The group address for identification of this KNX/IP gateway within the KNX bus 0.0.0
useNAT No Whether there is network address translation between the server and the gateway false
readingPause No Time in milliseconds of how long should be paused between two read requests to the bus during initialization 50
responseTimeout No Timeout in seconds to wait for a response from the KNX bus 10
readRetriesLimit No Limits the read retries while initialization from the KNX bus 3
autoReconnectPeriod No Seconds between connect retries when KNX link has been lost (0 means never). 0

Serial Gateway

The serial bridge accepts the following configuration parameters:

Name Required Description Default value
serialPort Y The serial port to use for connecting to the KNX bus -
readingPause N Time in milliseconds of how long should be paused between two read requests to the bus during initialization 50
responseTimeout N Timeout in seconds to wait for a response from the KNX bus 10
readRetriesLimit N Limits the read retries while initialization from the KNX bus 3
autoReconnectPeriod N Seconds between connect retries when KNX link has been lost, 0 means never retry 0

Things

device Things

basic Things are wrappers around an arbitrary group addresses on the KNX bus. They have no specific function in the KNX binding, except that if the address is defined the binding will actively poll the Individual Address on the KNX bus to detect that the KNX actuator is reachable. Under normal real world circumstances, either all devices on a bus are reachable, or the entire bus is down. When fetch is set to true, the binding will read-out the memory of the KNX actuator in order to detect configuration data and so forth. This is however an experimental feature very prone to the actual on the KNX bus.

Name Required Description Default value
address N The individual device address (in 0.0.0 notation) -
fetch N Read out the device parameters and address/communication object tables (requires the address) false
pingInterval N Interval (in seconds) to contact the device and set the thing status based on the result (requires the address) 600
readInterval N Interval (in seconds) to actively request reading of values from the bus (0 if they should only be read once at startup) 0

Different kinds of channels are defined and can be used to group together Group Addresses. All channel types share two configuration parameters: read, an optional parameter to indicate if the 'readable' group addresses of that Channel should be read at startup (default: false), and interval, an optional parameter that defines an interval between attempts to read the status group address on the bus, in seconds. When defined and set to 0, the interval is ignored (default: 0)

Standard Channel Types

Standard channels are used most of the time. They are used in the common case where the physical state is owned by a decive within the KNX bus, e.g. by a switch actuator who "knows" whether the light is turned on or of or by a temperature sensor which reports the room temperature regularly.

Channel Type "switch"
Parameter Description Default DPT
ga Group address for the binary switch 1.001
Channel Type "dimmer"
Parameter Description Default DPT
switch Group address for the binary switch 1.001
position Group address of the absolute position 5.001
increaseDecrease Group address for relative movement 3.007
Channel Type "rollershutter"
Parameter Description Default DPT
upDown Group address for relative movement 1.008
stopMove Group address for stopping 1.010
position Group address for the absolute position 5.001
Channel Type "contact"
Parameter Description Default DPT
ga Group address 1.009
Channel Type "number"
Parameter Description Default DPT
ga Group address 9.001
Channel Type "string"
Parameter Description Default DPT
ga Group address 16.001
Channel Type "datetime"
Parameter Description Default DPT
ga Group address 19.001

Control Channel Types

In contrast to the standard channels above, the control channel types are used for cases where the KNX bus does not own the physical state of a device. This could be the case if e.g. a lamp from another binding should be controlled by a KNX wall switch.

Channel Type "switch-control"
Parameter Description Default DPT
ga Group address for the binary switch 1.001
Channel Type "dimmer-control"
Parameter Description Default DPT
switch Group address for the binary switch 1.001
position Group address of the absolute position 5.001
increaseDecrease Group address for relative movement 3.007
frequency Increase/Decrease frequency in milliseconds in case the binding should handle that (0 if the KNX device sends the commands repeatedly itself) 0
Channel Type "rollershutter-control"
Parameter Description Default DPT
upDown Group address for relative movement 1.008
stopMove Group address for stopping 1.010
position Group address for the absolute position 5.001
Channel Type "contact-control"
Parameter Description Default DPT
ga Group address 1.009
Channel Type "number-control"
Parameter Description Default DPT
ga Group address 9.001
Channel Type "string-control"
Parameter Description Default DPT
ga Group address 16.001
Channel Type "datetime-control"
Parameter Description Default DPT
ga Group address 19.001

Group Address Notation

<config>="[<dpt>:][<]<mainGA>[[+[<]<listeningGA>]+[<]<listeningGA>..]]"

where parts in brackets [] denote optional information.

The optional < sign tells whether the group address of the datapoint accepts read requests on the KNX bus (it does, if the sign is there). With *-control channels, the state is not owned by any device on the KNX bus, therefore no read requests will be sent by the binding, i.e. < signs will be ignored for them.

Each configuration parameter has a mainGA where commands are written to and optionally several listeningGAs.

The dpt element is optional. If ommitted, the corresponding default value will be used (see the channel descriptions above).

Examples

Full Example

knx.things:

Bridge knx:ip:bridge [ 
    ipAddress="192.168.0.10", 
    portNumber=3671, 
    localIp="192.168.0.11", 
    type="TUNNEL", 
    readingPause=50, 
    responseTimeout=10, 
    readRetriesLimit=3, 
    autoReconnectPeriod=1,
    localSourceAddr="0.0.0"
] {
    Thing device generic [
        address="1.2.3",
        fetch=true,
        pingInterval=300,
        readInterval=3600
    ] {
        Type switch        : demoSwitch        "Light"       [ ga="3/0/4+<3/0/5" ]
        Type rollershutter : demoRollershutter "Shade"       [ upDown="4/3/50+4/3/51", stopMove="4/3/52+4/3/53", position="4/3/54+<4/3/55" ]
        Type contact       : demoContact       "Door"        [ ga="1.019:<5/1/2" ]
        Type number        : demoTemperature   "Temperature" [ ga="9.001:<5/0/0" ]
        Type dimmer        : demoDimmer        "Dimmer"      [ switch="5/0/0+<5/0/1", position="5/0/2+<5/0/3", increaseDecrease="5/0/4" ]
        Type string        : demoString        "Message"     [ ga="5/3/1" ]
        Type datetime      : demoDatetime      "Alarm"       [ ga="5/5/42" ]
    }
}

knx.items:

Switch        demoSwitch         "Light [%s]"               <light>          { channel="knx:device:bridge:generic:demoSwitch" }
Dimmer        demoDimmer         "Dimmer [%d %%]"           <light>          { channel="knx:device:bridge:generic:demoDimmer" }
Rollershutter demoRollershutter  "Shade [%d %%]"            <rollershutter>  { channel="knx:device:bridge:generic:demoRollershutter" }
Contact       demoContact        "Front Door [%s]"          <frontdoor>      { channel="knx:device:bridge:generic:demoContact" }
Number        demoTemperature    "Temperature [%.1f °C]"    <temperature>    { channel="knx:device:bridge:generic:demoTemperature" }
String        demoString         "Message of the day [%s]"                   { channel="knx:device:bridge:generic:demoString" }
DateTime      demoDatetime       "Alarm [%1$tH:%1$tM]"                       { channel="knx:device:bridge:generic:demoDatetime" }

knx.sitemap:

sitemap knx label="KNX Demo Sitemap" {
  Frame label="Demo Elements" {
    Switch item=demoSwitch
    Switch item=demoRollershutter
    Text   item=demoContact
    Text   item=demoTemperature
    Slider item=demoDimmer
    Text   item=demoString
    Text   item=demoDatetime
  }                
}

Control Example

control.things:

Bridge knx:serial:bridge [ 
    serialPort="/dev/ttyAMA0", 
    readingPause=50, 
    responseTimeout=10, 
    readRetriesLimit=3, 
    autoReconnectPeriod=1
] {
    Thing device generic {
        Type switch-control        : controlSwitch        "Control Switch"        [ ga="3/3/10+<3/3/11" ]
        Type dimmer-control        : controlDimmer        "Control Dimmer"        [ switch="3/3/50+3/3/48", position="3/3/46", increaseDecrease="3/3/49", frequency=300 ]
        Type rollershutter-control : controlRollershutter "Control Rollershutter" [ upDown="3/4/1+3/4/2", stopMove="3/4/3", position="3/4/4" ]
        Type number-control        : controlNumber        "Control Number"        [ ga="1/2/2" ]
        Type string-control        : controlString        "Control String"        [ ga="1/4/2" ]
        Type datetime-control      : controlDatetime      "Control Datetime"      [ ga="5/1/30" ]
    }
}

Bridge hue:bridge:bridge "Philips Hue Bridge" [ 
    ipAddress="...", 
    userName="..." 
] {
    Thing 0210 1 "Color Lamp" [ lightId="1" ]
}

knx.items:

Switch        demoSwitch         "Light [%s]"               <light>          { channel="hue:0210:bridge:1:color", channel="knx:device:bridge:generic:controlSwitch" }
Dimmer        demoDimmer         "Dimmer [%d %%]"           <light>          { channel="hue:0210:bridge:1:color", channel="knx:device:bridge:generic:controlDimmer" }