Voltage override in megatec and megatec-over-usb [was: Re: [Nut-upsdev] nut-2.0.5 megatec + Online Xanto]

[Carlos Rodrigues]

On 1/23/07, Henning Brauer <hb-nut at bsws.de> wrote:
> good new first: the megatec driverin 2.0.5 now works with the Online
> Xanto S3000R here - well, for the very basics.
>
> the UPS has NO way ofidentifying itself. It also does not respond to
> the power ratings query ("F"). I previously used a hacked up fentonups
> driver. This means the driver cannot figure out the battery voltage and
> thus no battery charge level, which is a problem in our setup.

You have to remember that the charge calculation in megatec is very
crude. The fact that it drops abruptly when the UPS goes on battery is
the most evident symptom. And there isn't any way around this. Not any
feasible one, that is.

So, if you are depending on the charge value for something important,
think twice about it.

> it is a 96V unit. the values I had in fentonups.h were
> +       { "XS3000R", "Online", "Xanto S3000R",
> +               1.81, 0.44, 1.81, 0.44, 165, 200, 240, 275, 1 },
> if there were a way to give the driver the desired voltage overriding
> the auto-detection, everything would work fine again...I had this
> hacked up for 2.0.3 at one point, but can't fine it right now. Carlos,
> didn't I mail hat before? in any case. does anyone have a better idea
> to solve this?

The version in the trunk has an option to do this ("battvolts=XX:XX")
since yesterday.You can get megatec.c and drop it over the 2.0.5
sources, it should build just fine.

It isn't in 2.0.5 because I didn't want to do it unless I was sure
there was no other way, and an option in a stable version is an option
that people may start using and thus can't be removed easily later on.
But my Mustek PowerMust broke, and I got a PowerWalker model that
looks just like the old one (software-wise, that is) but where the
charge gets calculated wrong. Talk about cheap hardware...

BTW, this model has an USB port along the RS232 one. So... I can help
if the project to create a "usbserial.o" communications layer picks
up. (If it doesn't, I will think about doing it on my own, based on
the code posted here a while ago, but I promise nothing. My time is
currently in short supply and I'm a complete newbie to this USB
protocol stuff.)

-- 
Carlos Rodrigues