[nSLUG] linux home or workplace automation and Universal Powerline Bus

George N. White III gnwiii at gmail.com
Sat Sep 20 14:52:09 ADT 2008

<http://en.wikipedia.org/wiki/Universal_powerline_bus> is a more
robust "fork" of X-10.
<http://linuxha.blogspot.com/2004/11/x10-alternative_05.html> for a
linux user's viewpoint,
to me the key thing is that the specs are published, so you aren't
stuck with the
vendor's windows software.

An example of what is available:
UPB thermostat (TU-16)

This is nice unit -- thinking about getting one at home, but after
some study I wish I'd put one in the machine room at work where the
A/C contractor left of the delay relay so the A/C breaker would trip every time
the power went off and the generator started up (A/C needs a minimum stop
time before it can be turned back on, which may mean that your equipment
shuts down due to overtemp even if you have A/C on generator -- nothing comes
easy when you are trying to get 7/24 reliability).

What I want to do:

1.  detect loss of line power (e.g., UPS goes to battery)
2.  with a short period (1-2 mins), initiate shutdown of the
     lower priority systems -- a) they don't get generator
     power so will have to be shutdown, and b) to reduce
     the heat going into the room
3.  if the generator comes on, start the A/C after the
     specified delay, otherwise, initiate shutdown of the
     remaining systems so they can do a clean shutdown
     before overtemp is triggered or the UPS dies.

Each of these events needs to be logged locally and
somewhere that is accessible from outside the
building (there have been a number of cases where
the building was closed and I had to wait to get back
in to access the damage -- for various reasons, we
have to evacuate the building when the power is off
for any extended period).   Many sites so this sort of
control using ethernet wiring, but using the power
line has some advantages since you need power
for anything to work, while ethernet tends to degrade
when there are power problems:

1.  there have been UPS failures in the network
closets.   We have had power outages that
killed UPS's  -- you can get really big spikes
when high voltage wires touch the lower
voltage lines.
2.  the network gets bogged down due to a bunch
of systems having problems, doing shutdowns, etc.,
Packets get lost, interfaces reset, default routes
are lost, etc.

A big question is whether UPB will work on a circuit
fed by a large high-end UPS.   UPB might be overkill,
but has the advantage of using COS parts and
a programming interface.

Does anyone have experience with UPB and linux?
Is there a local contractor with UPB expertise?

George N. White III <aa056 at chebucto.ns.ca>
Head of St. Margarets Bay, Nova Scotia

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