Most of the topology related issues are due to one or a combination of the following mistakes:
- the interface has the same Individual Address as one of the devices in the bus
- several devices in the bus have the same Individual Address
- the mainline and sub line of one or more Line Couplers are (physically) swapped
- the Individual Address of the target device does not match with its line: e.g. the Individual Address of the target device is 1.2.55 but it is physically connected to line 1.1
- the Individual Address of the interface does not match with its line: e.g. the Individual Address of the interface is 1.2.230 but it is physically connected to line 1.6
- two lines (e.g. 1.0 and 1.1) are physically connected (short circuit)
- a line has been connected to the power supply unit's 'auxiliary' connector instead of the 'KNX' (TP1) connector
Please note that the use of under-dimensioned power supply units (PSU) can have effects similar to topology mistakes.
Our recommendation is to build up the entire installation from scratch again, i.e. follow these steps:
- start with the first line, which contains only one PSU and an interface
- add devices and make sure that none of the above mentioned problems occur
- add another line and repeat step 2