[Nut-upsuser] Microdowell (cpsups) driver segfault

[Arjen de Korte]

>> after this it seems to work ok, even if it the numbers reported for
>> input voltage look a little low.
>> (205 to 211 in a country where nominal voltage is supposed to be 230).
>> Maybe it's just lousy power.(I have no easy way to verify)

I noticed that another (probably unrelated) driver scales the output
voltage, where a reading (from the UPS) of 208 is displayed as 230V. This
is probably needed, since the UPS can't output a value higher than 255,
which is too low for countries that have a nominal mains voltage of 220 to
240V.

Unfortunately, I don't know if we should multiply the value read from the
UPS by (230/208) or that we should add an offset (230-208).

> those numbers come directly from the ups itself.  My cyberpower unit
> displays the correct voltage (I am in the US, we have 120V line power);
> however, there are probably different versions of the firmware that might
> not have the correct voltage readings (or your power fluctuates a lot)..

What I would like to know, is what is read from the UPS. The output of
'upsc' can help here.

Best regards, Arjen