[Nut-upsuser] Interpreting data from 220V input APC UPS

[Greg Troxel]

John Ackermann N8UR via Nut-upsuser
<nut-upsuser at alioth-lists.debian.net> writes:

> I am monitoring via the SNMP driver an APC SmartUPS that has split
> phase (2L + neutral)  240V input and 120/120 volt outputs.  The data
> for the voltages is not what I'm expecting, and I am wondering how I
> should interpret it.

Wow, that sounds kind of industrial.  Model?

Is the input an L14-20P?  Or equivalent non-twistlock?

> Here is an example from upsc:
>
> input.L1-L2.voltage: 121
> input.L2-L3.voltage: 120
> input.voltage: 121.20
> output.current: 5.90
> output.L1-L2.voltage: 119
> output.L1.current: 5.90
> output.L2-L3.voltage: 119
> output.L2.current: 1
>
> The "input.voltage" value doesn't reflect the 240 volts that is
> actually being applied.  To get that, would I combine the L1-L2 and
> L2-L3 voltages?

I would address figuring this out as two steps.  One is to see what the
device actually sends and what makes sense there.  And then to see if
NUT is mapping or making synthetic.

I find it odd for the neutral to be labeled L2, as it seems to be.  I
would think there would be L1 and L2, both reported as phase-to-neutral.
You might see if there is confusion.

odd for output.L2.current, vs L3, given that voltage seems to be L1/L3
vs L2.

Probably the first voltage is mapped to just 'voltage' and probably it
would be better to use the L1/L3 voltage.  Similar for output.voltage.

output.current should probably be average if output.voltage is 240ish.
Or better yet 

> Note that the "output.current" value matches the L1 output current,
> ignoring the L2 current.  Perhaps that is a clue that the overall
> "input" and "output" values are not meaningful in this case?

yes, and they are perhaps mapped from something else?

> How should I interpret these values to know the actual input and
> output voltages and currents?

You're going to need to put a meter on it and compare to the reports, I
suspect.

First, see if you can get specs, and look at the snmp mib directly and
see what you can figure out.  Turn up debugging/verbose in nut.