[Nut-upsdev] NUT shutdown on 'building alarm' (

Arjen de Korte nut+devel at de-korte.org
Sat Jun 3 12:54:12 UTC 2006

Bruce Allen wrote:


> So I am checking with the list, to ask if the functionality that I
> describe above is already available with NUT or if I need to modify the
> driver so that a building alarm gets treated in the same way as an 'On
> battery' event.

I wouldn't mess with the driver. So far, there is little/no support for
these additional inputs that some UPS apparently have. Since people may
hook up quite different signals to them, this would inevitably mean that
you would need additional configuration parameters for them to define
the function. I foresee quite some additional coding needed and a lot of
confusion on how to use them.

Instead, it may be a lot easier to make use of the 'genericups' driver
and hook up your thermostat so, that it changes the serial input line
from the 'OL' the 'OB+LB' signal. This solution would not require any
changes to drivers and furthermore it would be immediately clear what
the reason of the shutdown is (and not 'faking' a power out/low battery
event where there isn't).

If you can find someone to make the necessary hardware (as simple as a
DB-9 plug, one 10k resistor and a couple of meters of wire), this may be
a much easier solution. Connect RI and DCD together, connect a resistor
from there to RTS and the thermostat to DTR. Then, the following entry
to your ups.conf file (change the port to whereever you connected this
to) would be sufficient to monitor your thermostat:

	driver = genericups
	port = /dev/ttyS0
	upstype = 1
	desc = "Room temperature limit switch"

Lastly, you would need some modifications to upsmon.conf to allow
systems you want to shutdown to monitor the thermostat.


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