Looking for a Power Line Communication bus

Projects Networking, Protocols, and Devices
1

Hi,

I'm currently using a KNX bus (EIB/Instabus) system for parts of my home automation.
Now I would like to create my own sensors on that bus but the interface modules are far too expensive and seem to have an ungenerous limit of 50mA 5V power supply.
So I'm trying to find a daisy-chained bus system with parallel power or power line communication.
I Have been trying to find out if PoE can be daisy-chained but it doesn't seem to support that?
And 230VAC PLC is too risky. Bulky components that will get hot and could cause fire in the walls.

What I need is a wire communication that can be at least 25 meters long, support at least 100mA per node and support at least 3-4 nodes per wire.
The speed can be quite low since it's only sensor data, no streaming, that will be transferred.
Any suggestions?

2

What about using RS485 over Cat5/6 cable. Two conductors for data and that leaves 6 for power. IIRC you can get 500mA per conductor (depends on distance and acceptable voltage drop of course) which would make 1.5A total, but you only need 400mA total it seems so if I have that wrong I'm sure it's still enough.

3

Though I have never used them myself maybe this is the sort of thing your looking for?