The KNX Easy Push Button Mode

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WEINZIERL ENGINEERING GmbH

The KNX Easy Push Button Mode
WEINZIERL ENGINEERING GmbH
Dr.-Ing. Th. Weinzierl
D-84558 Tyrlaching
www.weinzierl.de

The KNX standard is virtually inseparable from the ETS configuration software. It has proved
invaluable over the years and is particularly powerful in very complex networks.
Smaller installations can be better handled with a simpler technology called easy. Here, the KNX
Easy Push Button Mode is of special interest. Devices that support the Easy Push Button Mode
can be interconnected without a PC or additional controller. Thus, a sensor can be linked directly
to an actuator. To do so, both devices merely need to be put into the so-called link mode by
pushing a special button and they connect automatically.

1 Configuration modes in KNX
To put a device into operation, it is necessary to set up parameters and establish the connections
between the devices. The KNX standard defines various modes that can be used with different
media.
Configuration Mode

Common Kernel
(NL, TL & AL)
KNX Media (PL & LL)

Figure 1: System overview of KNX standard
System Mode was the first configuration mode to be developed. It was already defined in the
EIB system and requires a PC tool (ETS: EIB or Engineering Tool Software) to execute the
configuration procedure. This procedure is very powerful and can be used in very complex
installations. For the System Mode configuration, the manufacturer must make a product
database available for each device. The System Mode is designed primarily for trained
technicians with experience in KNX networks.

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The KNX Easy Push Button Mode

Easy Mode does not require a PC tool. The Easy Mode configuration is divided into various
submodes. Of these, the Easy Controller Mode and Easy Push Button Mode will continue to be
of interest in the future. As its name indicates, the Easy Controller Mode requires a control
device in the KNX network that executes the configuration process according to defined rules.
The Easy Push Button Mode does not require auxiliary tools and devices and will be described
more closely in this article.
Automatic Mode is a further configuration mode in KNX. It promises to implement a Plug-and-
Play configuration procedure that does not require intervention by the user. Because the
Automatic Mode only offers very limited functionality, there are currently no devices on the
market that support this mode.

2 Operating principle
Because a product database is not used in Easy Mode, the information about the functionalities
must be stored in the devices. For this purpose, a mechanism is defined on the basis of channels
and connection code CC that lays down the scope of functions of the device.
In terms of the Easy Mode, a channel is a set of communications objects and parameters that are
functionally related. Together, the communications objects of a channel form an interface to a
channel of the communications partner. Although a channel can have inputs as well as outputs, it
is categorized as either a sensor or actuator channel.

Figure 2: Excerpt from the available connection codes in KNX Supplement 12

To be able to determine which links need to be created, each communications object is assigned
a connection code. This code not only defines the respective data format but also describes the
usage of the data point. For example, binary outputs for a wind alarm and frost alarm have
differing connection codes. During the linking process, the data points of the activated sensor
channel are compared with those of the actuator channel. Communications objects with identical

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The KNX Easy Push Button Mode

connection codes are connected. It is important that one sensor channel is always connected to
one actuator channel. If a device has multiple channels, each channel must be linked separately.
For example, if one actuator channel is to be connected with two sensor channels, two linking
procedures are necessary.

Ch1 Switch PB Ch50 Binary switch no delay
GA1
On/Off CC01 On/Off CC01
Status On/Off CC02

Ch05 Dimming PB Ch55 Dimming Actuator
GA1 GA1
On/Off CC01 On/Off CC01
Bight/Dark CC06 GA2 GA2 Bight/Dark CC06
Value CC07
Ch = Channel Code Status On/Off CC02
CC = Connection Code
Status Value CC 08
GA = Group Address
Figure 3: Principle of the Easy Mode configuration

In the Easy Controller mode, the information about channel details is read out and interpreted by
the controller. In contrast, in the Easy Push Button Mode, the link possibilities are evaluated
during the link procedure. What makes the Push Button Mode so powerful is that it is truly an
intelligent network management system. Runtime telegrams are not used for the teach-in
process. Instead, links are negotiated, so to speak, between the communications partners during
the link sequence.
The A_NetworkParameter_Write service is used for transmitting link sequences. Because the
communications partner is not known at the beginning of a link sequence, the service is sent as a
broadcast. It contains the Object Type and Property ID parameters, which in this case are always
set to 0 for device object and 59 for PID_PB_CONFIG. There remains a data field with 4 bytes,
which contains the actual link commands with their parameters

Figure 4: Telegram format for A_NetworkParameter_Write

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The KNX Easy Push Button Mode

The following commands are defined for the link sequence:

• Enter_Config_Mode
• Start_Link
• Channel_Function_Actuator
• Channel_Function_Sensor
• Set_Channel_Param
• Channel_Param_Response
• Begin_Connection
• Set_Delete_Link
• Link_Response
• Stop_Link
• Quit_Config_Mode

The basic procedure is always the same. The user first activates the corresponding actuator
channel. This puts the channel into link readiness mode and it sends the Enter_Config_Mode
command to all. Then the sensor channel to be connected is activated. It starts the link procedure
with the Start_Link command. The devices then exchange their respective channel code with the
Channel_Function_Actuator and Channel_Function_Sensor commands. Subsequently, the
actuator has the option of setting parameters in the sensor. To do so, it sends the
Set_Channel_Param command, to which the sensor responds with Channel_Param_Response. If
no more parameters need to be set, the actuator hands over control to the sensor using the
Begin_Connection command. The sensor then transfers each link one by one using the
Set_Delete_Link command, which is confirmed by the actuator with a Link_Response. Links
from the actuator to the sensor are implemented in the same manner. In this case, however, the
actuator provides the group address within the response. The end of the link sequence is
indicated by the sensor using a Stop_Link, upon which the actuator also leaves the link mode by
sending the Quit_Config_Mode command. Hence, a dialog of sorts takes place between sensor
and actuator.
Notwithstanding its easy operation, this mode can readily be used to implement complex
functions. The assignments between sensor and actuators are not limited to 1:1 relationships.
Thus, a sensor can act on several actuators. Another example is that a switch actuator can be
controlled by multiple touch sensors. in parallel. In this way a total of n:n relationships are
possible, meaning that multiple sensors and multiple actuators can be connected to one function,
e.g. switching or dimming. The links can also be bidirectional. This is used primarily for the
transmission of active checkback signals.

3 Example
The figure below illustrates the following example: Each of the rocker switches of a touch sensor
is to control one switch actuator. Each rocker switch also has a status LED that indicates whether
the corresponding light is on or off.

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The KNX Easy Push Button Mode

Another touch sensor with only one rocker switch is to assume a central function. This
requirement would require a certain amount of programming experience when using the ETS.
However, it can also be effectively implemented in the Push Button Mode.

Switching
Switch actuator
Switching [out] Switching [in]
0/1/1 0/1/1
Status [in] 0/2/1
0/3/1
Switching [out]
0/1/2
Status [in] Status [out]
0.2.1 0/4/1 0/3/1 0.2.3

Switching
Switch actuator
Switching [out] Switching [in]
0/2/1 0/1/2
0/2/1

Status [out]
0.2.2 0/4/1 0.2.4

KNX
Figure 5: Example of a Push Button installation

The user runs through the following procedure. First the link mode of the first switch actuator is
activated. This is generally indicated by an LED. The actuator is now ready for the link process.
Then the touch sensor is activated. Because the sensor consists of two rocker switches, the
respective rocker switch must be selected for the link mode. The devices are organized in
channels according to the Easy Mode. In our example, a rocker forms one channel together with
the associated status LED. After both devices, i.e. touch sensor and switch actuator, are
activated, the link process begins and generally takes no longer than one second.
Subsequently, the second rocker switch is taught in to the other actuator in the same manner. All
that remains to be linked now is the switch for the central function. Because it is to control both
actuators, it must be taught in twice. One switch actuator is put into teach mode first, followed
by the switch for the central function. The last step is to activate the teach mode on the second
switch actuator, followed again by the switch. Finished.

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The KNX Easy Push Button Mode

On the bus, a link procedure looks as follows (recorded with Net’n Node bus monitor):
Src. Dest. R APCI AL-Data Link Commands ACK
Device 1 scans for a free individual address:
00.02.255 00.02.001 NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
00.02.255 00.02.001 R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
00.02.255 00.02.001 R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
00.02.255 00.02.001 R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
Device 1 scans for free group addresses:
00.02.001 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 21 ACK
00.02.001 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 22 ACK
00.02.001 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 23 ACK
00.02.001 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 24 ACK
Device 2 scans for a free individual address:
00.02.255 00.02.001 NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00 ACK
00.02.255 00.02.002 NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
00.02.255 00.02.002 R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
00.02.255 00.02.002 R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
00.02.255 00.02.002 R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00
Device 2 scans for free group addresses:
00.02.002 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 41 ACK
00.02.002 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 42 ACK
00.02.002 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 43 ACK
00.02.002 Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 44 ACK
Device 1 (Actuator) and Device 2 (Sensor) will be linked:
00.02.001 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=10 00 00 00 Enter Config M. ACK
00.02.002 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=20 00 C5 00 Start Link ACK
00.02.001 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=30 01 03 00 Ch. Fnc. Sens. ACK
00.02.002 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=40 00 02 00 Ch. Fnc. Act. ACK
00.02.001 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=70 00 00 00 Beg. Conn. ACK
00.02.002 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=80 02 00 00 Set Link ACK
00.02.001 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=91 02 C0 22 Link Resp. ACK
00.02.002 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=80 01 C0 43 Set Link ACK
00.02.001 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=90 01 C0 43 Link Resp. ACK
00.02.002 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=A0 00 00 00 Stop Link ACK
00.02.001 Broadc. NwParamWrite ObType=0(Device) PID=59 Info=B0 00 00 00 Quit Config M. ACK
Bi-directional runtime communication:
00.02.002 24/00/067 GrpValWrite Data=0x01 ACK
00.02.001 24/00/034 GrpValWrite Data=0x01 ACK
00.02.002 24/00/067 GrpValWrite Data=0x00 ACK
00.02.001 24/00/034 GrpValWrite Data=0x00 ACK
00.02.001 24/00/034 GrpValWrite Data=0x01 ACK
00.02.002 24/00/067 GrpValWrite Data=0x00 ACK
00.02.001 24/00/034 GrpValWrite Data=0x00 ACK
Figure 6: Interpreted recording of a Push Button Mode procedure on Twisted Pair

4 Media for the Easy Push Button Mode
The Easy Push Button Mode is fundamentally possible on all KNX media. However, the only
devices available on the market to date are those for KNX-RF.

4.1 Radio Frequency
Because wireless networks are generally relatively small, the Easy Mode is particularly suitable
for these networks. In addition, these networks have the special characteristic that they can
accommodate unidirectional devices such as handheld transmitters. From the perspective of the
user, these can be integrated in the network like bidirectional devices. During the linking
sequence, the actuator recognizes that the sensor is a unidirectional device and consequently
does not send responses to the sensor. This means that the unidirectional devices send out signals
when their link sequence is activated, regardless of whether or not anyone is listening.
On the medium, this link process looks as follows (recorded with Net’n Node bus monitor):

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The KNX Easy Push Button Mode

cEMI Header Serial Number Ctrl. Src. Dest. L. APCI Param T. Link Commands
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 2C 00 C5 05 Start Link
16 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 03 03 40 21 10 DD0 Response
22 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 0F 03 42 00 C5 21 01 10 3F 23.. DD2 Response
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 40 03 11 00 Channel Fct. Sensor
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 60 00 00 03 Parameter Response
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 60 01 00 04 Parameter Response
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 60 02 00 00 Parameter Response
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 60 03 00 01 Parameter Response
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 80 01 00 01 Set Link Switch On/Off
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 80 0C 00 02 Set Link Step Up/Dn
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 80 0B 00 03 Set Link Move Up/Dn
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 80 05 00 04 Set Link Dimm. Up/Dn
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B 80 08 00 05 Set Link Scene Num.
1B 29 09 02 07 03 00 C5 21 01 FF 55 00 E0 05 FF 00 00 08 03 E4 00 00 3B A0 00 00 00 Stop Link
Figure 7: Link sequence of a unidirectional handheld transmitter in the common EMI format

Figure 8: Handheld remote control and switch/blinds actuator for KNX-RF with Easy Push
Button Mode

In KNX-RF, the Push Button Mode is especially easy to implement since no individual address
and no group addresses have to be assigned. The standard individual address for KNX-RF is
0.5.255. The address is not changed in this mode since the devices can be identified using their
serial number, which is always sent along. The group addresses are only valid in connection with
the respective serial number. Thus, these can be assigned ex factory.

4.2 Twisted Pair
Prior to the link process in the Easy Push Button Mode for Twisted Pair, the devices must
receive an individual address and group addresses for the outputs. Because there is no central
tool in the system, the devices search for their addresses themselves. Basically, they select an
address in the address space for Easy Mode on Twisted Pair (0.2.00-0.2.254) and then check
whether the address is still free. The group addresses are then derived from the individual
address and are also checked to determine whether or not they are free. The Easy Push Button
Mode can be combined with all defined device models. Weinzierl Engineering has implemented
the Easy Push Button Mode with device model 0701/0705.

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The KNX Easy Push Button Mode

4.3 Powerline
For Powerline, no implementations for the Easy Push Button Mode are known at this time,
although this mode would be just as easy to implement with this technology as with Twisted
Pair. However, assignment of the domain address would have be defined.

4.4 KNXnet/IP
KNXnet/IP is now viewed as an independent medium in KNX. In the future, devices will be able
to communicate with the KNX network directly via IP. As full-fledged terminals, all
configuration modes will be available to these devices. Due to their complexity, many devices
will only support S-mode with the ETS. However, it is equally conceivable that these devices
could operate with the Easy Push Button Mode and it is likely only a question of time before the
first implementations are available.

Conclusion
As shown in the example above, the Easy Push Button Mode is very powerful yet easy to
operate. It is suitable primarily for smaller installations and especially for wireless networks.
Wireless networks are typically not as complex as installations with Twisted Pair.
For manufacturers, this mode is especially interesting for customers that do not have an ETS
available to them. These may be private networks or installers in countries where KNX is still
new. Combining Easy Mode and ETS configuration in devices safeguards the customer’s
investment in KNX. In Easy Mode, they can implement simple functions on their own and,
whenever necessary, call in a professional to reprogram the existing devices with the ETS and
implement complex functions.

Literature
[1] KNX Handbook, version 1.1, KNX Association, Brüssel, 2004

[2] Weinzierl, Thomas: Netzwerk-Management in KNX-RF Netzwerken; „Drahtlose
Nahbereichsnetze“, Design & Elektronik; München, 04. April 2006;

[3] Weinzierl, Thomas: KNX-RF Wireless alternative in KNX; KNX Journal 1-2006; KNX
Association Brüssel

[4] Weinzierl, Thomas: Stack Implementation for KNX-RF; KNX Scientific Conference 2005;
Pisa (Italy), September 2005

[5] Weinzierl, Thomas: A new development kit for EIB/KNX devices based on TP-UART
chip; Proceedings KNX Scientific Conference 2002, München, October 2002

[6] Additional information on www.weinzierl.de

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