[Nut-upsdev] [nut-commits] svn commit r1765 - in trunk: . drivers man

Arjen de Korte nut+devel at de-korte.org
Mon Feb 16 12:45:31 UTC 2009


Elio,

>>>>> 629                         dstate_setinfo("ups.realpower", "%d",
>>>>> (int)((float)(p[4]*256 + p[5]) * 0.6)) ;

[...]

>> The output in W is 0.6 * VA
> This is getting confusing. Please explain what is reported here.

Can you please explain what is measured here? For the upcoming  
nut-2.4.1 release I will comment this part out, as I believe this to  
be in error.

Note that while the relationship

     ups.realpower.nominal = 0.6 * ups.power.nominal

may be perfectly valid for this range of UPS (rated W will be  
somewhere between 0.6 and 0.9 rated VA for most if not all UPS  
devices), there is no way to make this assumption for

     ups.realpower = 0.6 * ups.power

which is the actually delivered W and VA. This relationship depends on  
the characteristics of the load (not the UPS). So you can't calculate  
one by multiplying by a fixed value (this has to be measured).

Best regards, Arjen
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