CBus introductory course

["Paul Robinson" <ukcueman@xxxxxxx>]

Today I went on the first of the two day introductory course for CBus.

So, was it worth my time? I would say definitely so. First of all, even
though I have a computing background, some of the restrictions and the way
some of the programming is not obvious. I can imagine wasting time on
figuring out some things that I got for free from the course. It was also
good to get hands-on with the 240V side of things too.

There have also been little useful snippets of information that I didn't
know. One little gem that I didn't know (and would have been useful) is
that
running CBus cat5 alongside other cat5 is not a good idea. The argument
against this is that it will cause induction within the other cables - much
as with AC stuff. Niall suggested that DC is actually worse than AC at
this.
Clipsal recommend a minimum distance of 60mm between CBus cat5 and other
cat5.

Perhaps some of the electronics buffs here could present an opinion on
this.
CBus runs (supposedly) at 36V DC but in practice will run at around 30V
(ish). Cbus units will happily work down to 15V, and if units are added in
series, the voltage will drop. Most units use 18mA. In my case, I will use
14 switches and an (at present) unknown number of PIRs, light/temperature
sensors etc. This means my switches (alone) will draw about 14*18 = 252mA.

Considering a worst case scenario of all cables being routed together with
a
load of this magnitude (or perhaps more with PIRs):
(1) Can anyone tell me whether inductance problems will be affected by the
choice of using star wiring for cbus units or daisy chained?
(2) How much of an effect might this have on other cat5-based services?

Thanks,
Paul