[Nut-upsuser] Unsupported UPS using megatec_usb

Jamie Thompson lists.nut-upsuser at jamie-thompson.co.uk
Fri May 16 22:40:04 UTC 2008

Alexander I. Gordeev wrote:

> This is expected because megatec_usb doesn't use /dev/usb/hiddev0 :)
> It should be something like /dev/bus/usb/<bus>/<device>.
> Btw, port variable from ups.conf is ignored so leaving 'auto' is ok.

Ok, I've set the permissions manually, and now have control of my UPS via nut on my test machine.

I am able to disable the beeper, despite the status always reading as off, but nothing else seems to work? load.off has no effect, nor does any other 
command, seemingly.

I've no prior experience with any UPSes, so I wonder if you could let me now if the following experience is common.

The apparent maximum voltage of the battery is 12.8v.

I've hooked up a monitor to drain it, and once the battery voltage gets down below 11v the overload beeper starts up (which cannot be disabled), and 
after a very short period of time the ups shuts off the monitor, upon which the voltage jumps back up to 11.30v, and then again after a short interval 
the UPS shuts off.

Is it normal for the UPS to have trouble with voltages so close to the full capacity of the battery?

The output of the UPS when it's at the point of shutting off the monitor immediately:
> battery.charge: 89.8
> battery.voltage: 11.50
> battery.voltage.nominal: 11.5
> driver.name: megatec_usb
> driver.parameter.battvolts: 0.0:12.8
> driver.parameter.mfr: Plexus
> driver.parameter.model: 500VA
> driver.parameter.pollinterval: 2
> driver.parameter.port: /dev/usb/hiddev0
> driver.parameter.vendorid: 0001
> driver.version: 2.2.1-
> driver.version.internal: 1.5.9
> input.frequency: 50.0
> input.voltage: 0.0
> input.voltage.fault: 165.0
> output.voltage: 230.0
> output.voltage.nominal: 230.0
> ups.beeper.status: disabled
> ups.delay.shutdown: 0
> ups.delay.start: 2
> ups.load: 100.0
> ups.mfr: Plexus
> ups.model: 500VA
> ups.serial: unknown
> ups.status: OB
> ups.temperature: 0.0

Interestingly, the status seems to have changed to "OFF" once I plugged it back into the mains. I believe I also saw "OL" in that field at one point.

...and the reported commands are:
> test.battery.start.deep - Start a deep battery test
No effect
> test.battery.start - Start a battery test
No effect
> test.battery.stop - Stop the battery test
No effect
> shutdown.return - Turn off the load and return when power is back
No effect
> shutdown.stayoff - Turn off the load and remain off
No effect
> shutdown.stop - Stop a shutdown in progress
No effect
> load.on - Turn on the load immediately
No effect
> load.off - Turn off the load immediately
No effect
> reset.input.minmax - Reset minimum and maximum input voltage status
Not sure how to test
> reset.watchdog - Reset watchdog timer
Not sure how to test
> beeper.toggle - Toggle the UPS beeper

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