[Nut-upsdev] APC Back-UPS 500

Rob Crittenden rcrit at greyoak.com
Fri Dec 30 19:15:07 UTC 2005

Charles Lepple wrote:
> On 12/29/05, Rob Crittenden <rcrit at greyoak.com> wrote:
>>I'm using nut 2.0.2 from Fedora Core 4 and had some trouble getting my
>>APC Back-UPS 500 working. I ended up having to rebuild the RPM myself
>>after making some code changes.
>>I had to increase the upsd synchronization timeout from 5 to 15 seconds.
>>It seems like 10 is the sweet spot but allowing a few extra seconds
>>doesn't seem to hurt anything. At 5 the UPS would timeout 5 out of 6 times.
> Depending on which timeout this is (I don't have the code handy), this
> might be something that could be exposed as a configuration variable.
> I think some of the MGE USB UPSes take a while as well, due to the
> slow internal baud rate, and the low-speed USB transfers.

Yup, sounds like a great idea to me.

>>The second problem is that my UPS, a USB model using the newhidups
>>driver, doesn't send PresentStatus (840002) in its updates. This means
>>that ups.status is always empty and upsmon has a fit over it.
>>My fix was to simply remove "PresentStatus." from the ups.status entries
>>in apc-hid.h. I haven't been able to come up with any sort of
>>semi-elegant solution for this. My fix could break any UPS that relies
>>on PresentStatus for its updates.
> Does the debug output indicate an alternative variable that provides
> on battery/online status? (In this case, '-D -D' is probably a decent
> debug level for newhidups.)

Sorry, I wasn't clear. Normally ups.status, at least in apc-hid.h, 
consists of UPS.PowerSummary.PresentStatus.ACPresent, Discharching, 
Charging, BelowRemainingCapacityLimit, etc.

I have the variables UPS.PowerSummary.ACPresent, Discharging and 
Charging available but there is no path for 
UPS.PowerSummary.PresentStatus. So by removing the PresentStatus from 
apc-hid.h I can get direct access to those variables. It is probably a 
bucket issue. On some UPS's these are dropped into the PresentStatus 
bucket, in others just in PowerSummary.

I haven't actually done a "pull the plug and watch the status change" 
test yet since I have equipment plugged in at the moment, but since I 
see those status variables I have some amount of faith that it will do 
the right thing.


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