[Nut-upsuser] nut-scanner / USB?

[Bruce Pleat]

Just had a lengthy conversation with someone, thought it was on the list,
here's the recap.

I tried on different computers - Pi 2 Zero W, Pi 5, higher-end AMD.  All
Linux Debian Trixie, which is what I run.
Was through powered hubs. Tried different powered hubs, different USB ports
on each computer, different cables.  Tried the "good" cable (the one for
the UPS that returned 100% of the time, and it made no difference on the
other UPS, and their cables worked fine on the one "good" UPS.

I guess the basic question is, is this common with less-expensive UPS like
those, that they're not reliably connected?
If not, not sure what else I can do to test?

Are there configuration settings to control how long nut-scanner collects
info, or what fields it requires before returning info?
Perhaps something like a timeout setting or cache or ?
(I didn't dive into the code.)



On Mon, Sep 7, 2026 at 5:29 PM Bruce Pleat <bpleat at gmail.com> wrote:

> Hi,
> I recently build 2.8.5 from the latest (as of a week ago) code.
> I noticed that nut-scanner produces very inconsistent results for some of
> my 6 UPS.
> There's quite the spread in both how often they respond and how well one
> of them responds.  In 600 runs, with varying pauses between them, with two
> analyses performed, and with uniq giving the frequency:
>      15
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501"
>      66
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="ABST600",vendor="CPS"
>     319
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="SL
> Series",vendor="CPS"
>     370
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="CP685AVR-G",vendor="CPS"
>     500
> USB:driver="usbhid-ups",port="auto",vendorid="051D",productid="0002",product="Back-UPS
> ES 600M1",serial="4B1936P07680",vendor="American Power Conversion"
>     500
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="ABMT1500",serial="FCEMU2001294",vendor="CPS"
> ...so two are reliable, four are not.
>
> With a slightly different call to get the USB bus info (since two of the
> UPS are identical models):
>       2
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",bus="001",busport="002"
>      56
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="ABST600",vendor="CPS",bus="001",busport="003"
>      59
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="ABST600",vendor="CPS",bus="001",busport="001"
>      73
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="SL
> Series",vendor="CPS",bus="001",busport="002"
>      81
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="CP685AVR-G",vendor="CPS",bus="001",busport="002"
>     101
> USB:driver="usbhid-ups",port="auto",vendorid="0764",productid="0501",product="ABMT1500",serial="FCEMU2001294",vendor="CPS",bus="001",busport="001"
>     106
> USB:driver="usbhid-ups",port="auto",vendorid="051D",productid="0002",product="Back-UPS
> ES 600M1",serial="4B1936P07680",vendor="American Power
> Conversion",bus="001",busport="003"
>
>
> bus="001",busport="001",vendorid="0764",productid="0501",vendor="CPS",product="ABMT1500",serial="FCEMU2001294"
>
> bus="001",busport="001",vendorid="0764",productid="0501",vendor="CPS",product="ABST600",serial=
>
> bus="001",busport="002",vendorid="0764",productid="0501",vendor="CPS",product="CP685AVR-G",serial=
> bus="001",busport="002",vendorid="0764",productid="0501",vendor="CPS",product="SL
> Series",serial=
>
> bus="001",busport="002",vendorid="0764",productid="0501",vendor=,product=,serial=
> bus="001",busport="003",vendorid="051D",productid="0002",vendor="American
> Power Conversion",product="Back-UPS ES 600M1",serial="4B1936P07680"
>
> bus="001",busport="003",vendorid="0764",productid="0501",vendor="CPS",product="ABST600",serial=
>
> I believe both the USB bus is not always reporting all six (I checked that
> and saw lsusb not giving consistent results), but also the UPS themselves
> seem to be inconsistent.
>
> I tried swapping cables, changing the USB port on the test computer, and
> more.
>
> I'd rather not waste perfectly good UPS, and I'd rather not go live with
> this unreliability.
>
> Thoughts on how I can diagnose this further?
>
> Thanks.
>
>
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