Nut upsuser - Mar 2008 - problem with output voltage on a mustek ups

Hi there

I have a Mustek PowerMust 1000 USB using serial port /dev/ttyS0.
I use nut 2.2.1 with the megatec driver on Debian Lenny (testing),
running on an AMD64 X2.
(I was using a Debian Etch as slave, but to keep it simple I turned it off)


My problem is that sometimes the UPS is running OK, but when the
message "UPS is trimming incoming voltage" appears on knutclient (i.e.
OL TRIM in nut), I have something like

Input Voltage
	241.1
Output Voltage
	202.0
	nominal 220.0 ???

This output voltage is too low! I  think power spikes may be better
than using this voltage.

I don't know if the problem is the UPS or from communication with it.
Can you please help me checking  this? I have search on the web and on
the nut mailing-lists, but I didn't found anything.

Thanks,
Pedro.

> My problem is that sometimes the UPS is running OK, but when the
> message "UPS is trimming incoming voltage" appears on knutclient
(i.e.
> OL TRIM in nut), I have something like
>
> Input Voltage
> 	241.1
> Output Voltage
> 	202.0
> 	nominal 220.0 ???
>
> This output voltage is too low! I  think power spikes may be better
> than using this voltage.
I don't think so. Unless the input voltage is exceptionally low (but then
the UPS would switch to battery), the power supply will not be hurt by it.
An input voltage that is too high, will hurt it, so I wouldn't worry about
it.
> I don't know if the problem is the UPS or from communication with it.
> Can you please help me checking  this? I have search on the web and on
> the nut mailing-lists, but I didn't found anything.
NUT has no way to control is the UPS is using BOOST/TRIM, this is
something that the UPS decides all by itself. So there is nothing we can
do about it, complain to Mustek if you feel this is wrong.

Best regards, Arjen
-- 
Eindhoven - The Netherlands
Key fingerprint - 66 4E 03 2C 9D B5 CB 9B  7A FE 7E C1 EE 88 BC 57

Quoting Arjen de Korte <nut+users at de-korte.org>:
>> My problem is that sometimes the UPS is running OK, but when the
>> message "UPS is trimming incoming voltage" appears on
knutclient (i.e.
>> OL TRIM in nut), I have something like
>>
>> Input Voltage
>> 	241.1
>> Output Voltage
>> 	202.0
>> 	nominal 220.0 ???
>>
>> This output voltage is too low! I  think power spikes may be better
>> than using this voltage.
>
> I don't think so. Unless the input voltage is exceptionally low (but
then
> the UPS would switch to battery), the power supply will not be hurt by it.
> An input voltage that is too high, will hurt it, so I wouldn't worry
about
> it.
Do you mean the computer's power supply? But it is supposed to run on
220-230V not on 202V! Isn't this a problem?
>
>> I don't know if the problem is the UPS or from communication with
it.
>> Can you please help me checking  this? I have search on the web and on
>> the nut mailing-lists, but I didn't found anything.
>
> NUT has no way to control is the UPS is using BOOST/TRIM, this is
> something that the UPS decides all by itself. So there is nothing we can
> do about it, complain to Mustek if you feel this is wrong.
I thought that issuing
   upscmd -u admin -p password mustek reset.input.minmax
might make the UPS "re-think" if it should trim the output voltage,
but I seems I was wrong. It does nothing.

I will certainly complain to Mustek, as they say 220-230V output.
>
> Best regards, Arjen
Thanks again,
Pedro.
> --
> Eindhoven - The Netherlands
> Key fingerprint - 66 4E 03 2C 9D B5 CB 9B  7A FE 7E C1 EE 88 BC 57
>

On Thu, Mar 6, 2008 at 6:22 AM,  <pmjorge at lip.pt>
wrote:
>  Input Voltage
>         241.1
>  Output Voltage
>         202.0
>         nominal 220.0 ???
>
>  This output voltage is too low! I  think power spikes may be better
>  than using this voltage.
Is this indicated by the UPS, or did you measure this voltage externally?

Arjen has mentioned this before, but the values returned by UPSes are
generally not calibrated.

-- 
- Charles Lepple