[Nut-upsuser] Using NUT to detect a normally closed circuit opening

[James Smith]

So how do I make sure it never sees the LB event (or ignores it)? 

The sensor is in an oily boiler room that is prone to water spillages etc., our only semi reliable option was a mechanical thermostat style sensor strapped directly to a pipe, so usb is pretty much out of the question. 
All I am using this for is to email our maintenance crew if the temp in the cooling tower pipe goes over-range as it indicates a situation that can usually easily be remedied before it becomes an issue, it has no relation whatsoever to the power situation where the NUT software is, I'm just using a framework that's already there for something completely unrelated.

The point about the short is a valid one, but I don't think it will be an issue (if it ever does become an issue, I can change the sensor out for a normally open one and change the driver file accordingly)

-----Original Message-----
From: nut-upsuser-bounces+james.smith=jofco.com at lists.alioth.debian.org [mailto:nut-upsuser-bounces+james.smith=jofco.com at lists.alioth.debian.org] On Behalf Of Arjen de Korte
Sent: Wednesday, June 22, 2011 11:10 AM
To: nut-upsuser at lists.alioth.debian.org
Subject: Re: [Nut-upsuser] Using NUT to detect a normally closed circuit opening

Citeren James Smith <james.smith at jofco.com>:

> I now have everything in place and I get an email when the temp sensor 
> opens
>
> Question - what do I set so the system doesn't shut down when the 
> sensor stays open?

The system will only shutdown if you have an OB+LB event at the same time. As long as you make sure the system sees either OB or LB, but not both, you'll be fine.

> Can I just set SHUTDOWNCMD "" ?

This isn't needed.

Note that there is a fatal flaw in a setup where opening a contact triggers an event. You'll have no way to verify that there is not a short in your cable, short of raising the temperature periodically to see if you see something changing.

I wouldn't recommend using a temperature switch for anything else than a redundant over temperature kill switch, especially since USB connected temperature sensors are very cheap nowadays. This would allow you to monitor the health of your alarm system much easier.

Best regards, Arjen
--
Please keep list traffic on the list (off-list replies will be rejected)



_______________________________________________
Nut-upsuser mailing list
Nut-upsuser at lists.alioth.debian.org
http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/nut-upsuser