Make sure your KNX installation is functioning - A guest post by “E-Necker”
A system integrator is always judged by the result. Therefore, it is crucial for a new installation to run smoothly. KNX system integrator Mario-Pascal Necker explains in 7 steps the content of a comprehensive system documentation, in order to make sure the flawless functioning of a KNX installation:
1. Checking the cable length
This guarantees the compliance of the maximal allowed length. This ensures the adherence of the maximal physical values, which ensures the correct transmission of telegrams. In addition to that, tolerance times will also be tested to guarantee the compliance of the maximal allowed time.
2. Visual inspection
Looking at correct marking of the end of the bus line is another factor, which determines the working of a KNX installation. This needs to be done so that another electrical engineer can easily find the correct spot. Furthermore, the installation of a KNX surge protection is of great importance because it prevents damage from being done to the KNX parts.
3. Check for illegal line connections
The KNX-bus is to be wired in a star-shape or tree structure. When testing the line link, a loop must be excluded. A loop would cause disturbances and malfunctions. Furthermore, a loop would make some safety concepts less effective. Loops often get unintentionally created when multiple lines or line repeaters are in use.
4. The bus cable´s isolation resistance must be measured
By doing this you will be able to detect damaged lines. The test needs to be done without an over-voltage protection or any devices connected, otherwise you could seriously damage these connected devices. Through this method you find problems with the wiring.
5. Polarity tests must be carried out in all bus subscribers
This ensures that all subscribers are connected to the right polarity and also to guarantee that all telegrams are properly sending and receiving. Like the step before (4) this step also aims to detect problems in the wiring and to find damaged bus lines early.
6. Measure the voltage on the ends of the bus lines
There needs to be a minimum of 21V at the end of the lines. If these 21V are not reached one must consider the use of an additional power supply or a line repeater
7. Protocol all results
After all these steps one needs to protocol all the results. This protocol serves as the proof that the tests have been carried out.
Taking the checklist for installers by KNX Association into consideration, the system integrator will be able to present a fully functioning installation, which will also be tailored to the needs of the customers – The perfect mix for success.