From: Landry Breuil <landry@openbsd.org>
Subject: Re: upd(4): add more sensors (load, power..)
To: Walter Alejandro Iglesias <wai@roquesor.com>, tech@openbsd.org, sthen@openbsd.org
Date: Thu, 21 Nov 2024 18:02:31 +0100

Le Tue, Nov 19, 2024 at 10:51:00AM +0000, Stuart Henderson a écrit :
> On 2024/11/19 10:19, Walter Alejandro Iglesias wrote:
> > On Sat, Nov 16, 2024 at 12:30:47PM +0100, Landry Breuil wrote:
> > > so if you have an upd(4) somewhere and you have sensors, i'll be glad to
> > > know if:
> > > - you get more sensors and they make sense
> > > - you get values that make more sense than before
> > > - you had a value for RunTimeToEmpty that made sense and now doesn't
> > >   (same for AtRateTimeToEmpty/AtRateTimeToFull if you have them)
> > > - it now breaks/detaches/reattaches
> > > 
> > 
> > With your patch RunTimeToEmpty now tells the true.
> > 
> > I guess PercentLoad is ok.

Thanks for the report, that seems to confirm that all EATON UPSs need
the same treatment.

> > Regarding VoltageDc and ConfigApparentPower I don't know what they mean.
> 
> VoltageDc is the voltage at the battery (could either be DC charger
> voltage or battery voltage I suppose). Unless your batteries are on
> several rows of shelves, that's not reported correctly. ($work 40kVA
> UPS has several rows of shelves and DC voltage is 270V so 828V would
> be a huge one :-)
> 
> Apparent power is related to the current drawn (whereas "true" power
> depends on power factor). It should be somewhere in the region of W
> drawn but not exactly the same.
> 
> The unit for apparent power should be VA, not W.

Oh.. that explains why the strange values. Would it make sense then to
convert (and how) those VA to W for "end-user values" ?

> I'm not sure if "ConfigApparentPower" would be actual use or the max
> allowed by the UPS; "Config" suggests possibly the latter.

After rereading the spec and a bit of the nut code, it seems to me that
ConfigApparentPower correspond to the max allowed by the UPS. I don't
think it really makes sense to report a constant in sensors, so i'd be
tempted to leave that one out.

I managed to configure nut to talk to my UPS and it reports sensible
values (eg ones that match the LCD values):
ups.load: 16
ups.power: 98
ups.power.nominal: 650
ups.realpower: 63
battery.runtime: 2050

i'll have to digest the laaarge output produced by usbhid-ups -DDDDD to
understand what is read from which usb register/reportid, and how those
are converted to the end-user values.

my idea would be to:
- enable the PercentLoad sensor
- fix RunTimeToEmpty for EATON models
- and eventually figure out how to massage the power/realpower values
  from what i've read, converting from VA ? the USB HID spec doesn't
seem to say those are VA but W, but i might be wrong here.

Landry