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I can't figure out where to connect an KNX IP interface (e.g. Siemens N148) in a twisted pair topology with multiple lines interconnected with line-couplers. Should I connect it to one of the lines and assign it a participant address on this line (e.g. 1.1.42) ? Should I connect it to the backbone line, wich does not exist today (with an additional area-coupler to create the backbone line) in order to assign it a participant address on the line 0 (e.g. 0.0.42) ? Note : Ok, it should be easier to use à KNX IP router (e.g. Siemens N146) connected to the main line, but is there a way to use a simple KNX IP interface with only IP-Tunneling communication mode ? |
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I suppose you need a IP-interface instead of a USB-interface. In that case you can place it wherever you like. But the most logic way, of course, is to place it where you have the shortest route to all devices and that is normally the backbone (but in practice there´s no real difference where you place it). If you have multiple lines connected with line-couplers today then your backbone is the area-line 1.0. In this definition the backbone is the highest in the topology and in most projects you will never use area-couplers, just line-couplers. Thus, the backbone can be your area in smaller installation or the line connecting areas in bigger installations. Also keep in mind that the IP-interface has 2 different physical addresses, the one you define during commissioning with ETS and uses for download and the other one set by ETS as local interface address. |
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you can connect it wherever you want. just adress it properly. you must have one thing in mind: depends on line coupler configuration, but if you filtering telegrams, you'll see only telegrams in line where you install your IP interface. if you want to see telegrams from other lines, you have to stop filtering, or you can put adresses you want to listen in filter tables. sometimes it's better to install IP interface to backbone and allow telegrams that you want to listen to go out from line to mainline, and filter just from mainlne to line. this way you don't have large bus load inside your line where IP interface would have been. main question is: what is the purpose of this IP interface? |
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Thanks for your help. To Bjork: "the backbone is the highest in the topology". Ok, now everything is really clear for me. To Miro: "if you want to see telegrams from other lines, you have to stop filtering". A good reason to put the KNX IP interface on the backbone and filtering from mainline to line. Because the purpose of this IP interface is to permit access to the KNX bus from ETS3 or vizualisation software, all the telegrams are supposed to be able to reach the IP interface. |