[Nut-upsuser] Powerware 9120 / bcmxcp losing communication

David S. Madole david at madole.net
Tue Jun 22 14:54:19 UTC 2010

On 6/22/2010 10:36 AM, Chris Boot wrote:
> I just acquired a new UPS and have been trying to get it to work with NUT. It's an Eaton/Powerware 9120 700i with both USB and RS-232 interfaces.
> So I moved on to try the serial port instead. Here the UPS also regularly loses the connection but at least it doesn't lock the UPS right up - maybe that was a fluke. If I restart the driver, the communication is regained for a few minutes but then drops again. Below are excerpts from running '/lib/nut/bcmxcp -DDD -a pw9120'.
I had a similar problem using bcmxcp with an HP3000 XP unit.

Ultimately what fixed it was adding:

      pollinterval = 5

to the definition for the unit in ups.conf.

A value as low as 3 (compared to the default 2) seemed to be enough to 
fix the problem, I went to 5 for some extra margin. I think that 
sometimes the poll cycle takes more than two seconds and the next poll 
somehow steps on the tail of the previous one. Not sure if this is the 
same thing you are experiencing, but the symptom is the same.


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