Nut upsdev - Dec 2007 - [nut-commits] svn commit r1204 - in trunk: . drivers

Carlos Rodrigues wrote:
> Author: carlosefr-guest
> Date: Sat Dec 29 20:17:01 2007
> New Revision: 1204
> 
> Log:
> - drivers/megatec.c: detect OB status while OFF.
You've changed a bit more than this line suggests.

[...]
> @@ -565,10 +575,16 @@
>  	dstate_setinfo("input.voltage.fault", "%.1f",
query.fvolt);
>  	dstate_setinfo("output.voltage", "%.1f",
query.ovolt);
>  	dstate_setinfo("ups.load", "%.1f", query.load);
> -	dstate_setinfo("input.frequency", "%.1f",
query.freq);
>  	dstate_setinfo("battery.voltage", "%.2f",
query.battvolt);
>  	dstate_setinfo("ups.temperature", "%.1f",
query.temp);
>  
> +	/*
> +	 * The specification states this must be the input frequency, but
> +	 * some vendors use it as the output frequency. The safest bet is
> +	 * to just show the value without context and let the user decide.
> +	 */
> +	dstate_setinfo("frequency", "%.1f", query.freq);
> +
>  	charge = get_battery_charge(query.battvolt);
>  	if (charge >= 0) {
>  		dstate_setinfo("battery.charge", "%.1f", charge);
If the specification says 'input frequency', that's what it is. If
some
vendors don't follow this, that's their problem. In any case I'm
very
much against breaking the NUT variable naming convention for something
like this.

If this really is a consern (which I very much doubt), I suggest to
either drop this variable completely or reverse this change and put a
note in the man page that some devices don't follow the specification here.

Best regards, Arjen

On Dec 29, 2007 9:44 PM, Arjen de Korte <nut+devel at de-korte.org>
wrote:
> If the specification says 'input frequency', that's what it is.
If some
> vendors don't follow this, that's their problem. In any case
I'm very
> much against breaking the NUT variable naming convention for something
> like this.
According to "new-drivers.txt", I'm not breaking the variable
convention at all. And it was after reading that part of the
documentation that I thought this might make sense instead of keep
providing a variable with dubious/false meaning.

The problem with the specs, is that the only ones available seem to be
from specific vendors, so there isn't actually a "right" or
"wrong".
There is no standard (see the problem with some models having the OFF
flag enabled).
> If this really is a consern (which I very much doubt), I suggest to
> either drop this variable completely or reverse this change and put a
> note in the man page that some devices don't follow the specification
here.
Dropping this variable is not very nice, since the frequency is a very
good indicator of power quality. And there's something more to this
than a reverse of meaning from some vendors. My UPS (a standby model)
seems to be showing input frequency while there is line power, but
then it keeps showing a value even on battery. If you think about it,
it actually makes (some) sense. While on line power this is the
frequency directly from the input, but while on battery it is the
output frequency from the inverter. Ratings information also avoids
defining nominal frequency and voltage as either input or output.

Again, I'd like to hear from whomever wrote that bit in
new-drivers.txt what the intention was. If I'm interpreting it wrong,
I'll do the appropriate changes, no problems whatsoever.

-- 
Carlos Rodrigues