The KNX Easy Push Button Mode

Transcription

1 The KNX Easy Push Button Mode Dr.-Ing. Th. Weinzierl D Tyrlaching 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 Page 1/8

2 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 Page 2/8

3 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 On/Off CC01 GA1 Ch50 Binary switch no delay On/Off CC01 Status On/Off CC02 Ch05 Dimming PB On/Off CC01 Bight/Dark CC06 GA1 GA2 GA1 GA2 Ch = Channel Code CC = Connection Code GA = Group Address Figure 3: Principle of the Easy Mode configuration Ch55 Dimming Actuator On/Off CC01 Bight/Dark CC06 Value CC07 Status On/Off CC02 Status Value CC 08 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 Page 3/8

4 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 Page 4/8

5 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. Switch Switching actuator Switching [out] 0/1/1 Status [in] 0/3/1 Switching [out] 0/1/2 Status [in] 0/4/1 Switching [in] 0/1/1 0/2/1 Status [out] 0/3/ Switch Switching actuator Switching [out] 0/2/1 Switching [in] 0/1/2 0/2/ Status [out] 0/4/ Figure 5: Example of a Push Button installation KNX 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 Page 5/8

6 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: NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info= R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info= R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info= R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00 Device 1 scans for free group addresses: Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 21 ACK Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 22 ACK Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 23 ACK Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 24 ACK Device 2 scans for a free individual address: NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00 ACK NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info= R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info= R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info= R NwParamWrite ObType=0(Device) PID=61(PID_ADDR_CHECK) Info=00 Device 2 scans for free group addresses: Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 41 ACK Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 42 ACK Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 43 ACK Broadc. NetParamRead ObType=1(AddrTab) PID=23(ListGA) Info=01 C0 44 ACK Device 1 (Actuator) and Device 2 (Sensor) will be linked: Broadc. NwParamWrite ObType=0(Device) PID=59 Info= Enter Config M. ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info=20 00 C5 00 Start Link ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info= Ch. Fnc. Sens. ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info= Ch. Fnc. Act. ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info= Beg. Conn. ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info= Set Link ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info=91 02 C0 22 Link Resp. ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info=80 01 C0 43 Set Link ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info=90 01 C0 43 Link Resp. ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info=A Stop Link ACK Broadc. NwParamWrite ObType=0(Device) PID=59 Info=B Quit Config M. ACK Bi-directional runtime communication: /00/067 GrpValWrite Data=0x01 ACK /00/034 GrpValWrite Data=0x01 ACK /00/067 GrpValWrite Data=0x00 ACK /00/034 GrpValWrite Data=0x00 ACK /00/034 GrpValWrite Data=0x01 ACK /00/067 GrpValWrite Data=0x00 ACK /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): Page 6/8

7 cemi Header Serial Number Ctrl. Src. Dest. L. APCI Param T. Link Commands 1B C FF E0 05 FF E B 2C 00 C5 05 Start Link C FF E0 05 FF DD0 Response C FF E0 05 FF F C F 23.. DD2 Response 1B C FF E0 05 FF E B Channel Fct. Sensor 1B C FF E0 05 FF E B Parameter Response 1B C FF E0 05 FF E B Parameter Response 1B C FF E0 05 FF E B Parameter Response 1B C FF E0 05 FF E B Parameter Response 1B C FF E0 05 FF E B Set Link Switch On/Off 1B C FF E0 05 FF E B 80 0C Set Link Step Up/Dn 1B C FF E0 05 FF E B 80 0B Set Link Move Up/Dn 1B C FF E0 05 FF E B Set Link Dimm. Up/Dn 1B C FF E0 05 FF E B Set Link Scene Num. 1B C FF E0 05 FF E B A 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 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 ( ) 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/ Page 7/8

8 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 ; 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 Page 8/8