[Nut-upsuser] APC SmartUPS switches off with no reason

[Matus UHLAR - fantomas]

On 09.07.14 15:08, Ivan Kuznetsov wrote:
>One our customer has two Linux HP-branded servers powered from 
>"clasic" APC Smart-UPS 2200 RM 2U (p/n SUA2200RMI2U). It is connected 
>to first server via RS232c port with APC-branded cable. We have 
>installed NUT 2.6.4 with apcsmart driver. This setup works fine for 
>months. Two weeks ago all the hardware powered from the UPS started 
>to switch off occasionally while on line power. The UPS switchs off 
>too and need to be turn on manually. No any warnings or so logged by 
>NUT. UPS load is <25-30%, battery is ok. With disconnected control 
>cable the UPS forks as desired, no switch offs for 6 days. When 
>customer connects the cable back the UPS switchs off after ~12 hours. 
>It looks like the UPS recives 'instant poweroff' command via 
>interface with no reason
>
>What can be a diagnostic procedure?

Hello,
20 years ago I was working with APC Smart UPS (1500 iirc) and I have noticed
this behaviour:

when power fell off with cable plugged in (powerchute not configured), the
UPS turned power to my computer a few seconds after the outage.

When the cable was not plugged in, the UPC did hold the power until it
discharged.

Therefore I think that the APC UPS needs to communicate with the computer
when it's connected and it loses input power, otherwise it shuts output
power down...

I feel there something strange about APC UPS...

-- 
Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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