Function and Filtering
ETS fills the filter table of the coupler automatically during download: all GAs present in the target line are entered. Telegrams for GAs not present in the target line are discarded, this relieves the line.
A line coupler also isolates line faults: a short circuit on line 2 does not bring down line 1. This is especially important in larger installations (commercial) where failure of individual lines should not shut down the entire system.
Types and Use
A line coupler connects the main line and a sub-line (physical addresses X.0.0 and X.Y.0). An area coupler connects the backbone and an area line (X.0.0). KNX IP routers fulfil the same function over IP.
For typical single-family homes with fewer than 50 devices, no coupler is needed. From around 64 devices, when logical separation (floor = line) is desired, or to relieve power load (second power supply on its own line), a coupler makes sense.
Key Facts
- Filters telegrams based on the GA table
- ETS fills filter table automatically
- Galvanic isolation between lines
- Line faults are isolated at the coupler boundary
- Physical address of coupler ends in .0 (e.g. 1.2.0)