[Nut-upsuser] [Nut-upsdev] Plexus UPS 1000V - megatec_usb

Arjen de Korte nut+devel at de-korte.org
Fri Dec 28 15:28:33 UTC 2007

>> [snip] Either way, I'll know
>> what's needed, if an option to interpret the "OFF" bit the other way
>> around, or just ignore it.
> I've just commited a workaround for this in the development trunk.
> Just add "ignoreoff" to your "ups.conf" and it should do the trick.

Still I think the 'megatec' driver as it is (and a good deal of other
drivers by the way too) treat the 'OFF' state in a way it is not intended
to be used. Currently, if it notices this status (be it right or wrong),
it will disregard the 'OL' and 'OB' states. This is wrong. A UPS should
*always* be setting either the 'OL' or 'OB' to indicate line status.

The 'OFF' status explicitly only tells whether or not the UPS is powering
the load or not. Even when it is not powering the load, it is still
meaningful to know if line power is present. So 'OL OFF' *is* a valid
state. The documentation in 'new-drivers.txt' was amended to make this
more clear to developers, since it has been confusing driver authors too
many times in the past.

Therefor, I propose to relax the interpretation of the status bits in the
'megatec' driver, to allow the interpretation of 'OL' and 'OB', even if we
already think/know the output is switched off.

Best regards, Arjen

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