[Ovmsdev] New Metric Units
Michael Balzer
dexter at expeedo.de
Tue Nov 8 21:01:36 HKT 2022
That's basically a good approach, but be aware 'IsDefined()' has an
ambiguous meaning here, as with the API stem "OvmsMetrics" it would
naturally be expected to mean "is this metric defined", not "does this
metric have a defined value".
An undefined metric currently can be derived from 'Values()' returning
undefined, but that's more an undocumented side effect than intended.
Maybe 'GetDefined()' could be a better name, leveraging this behaviour,
i.e. returning 'undefined' for an actually undefined metric, and 'null'
for a defined metric without a value.
Regards,
Michael
Am 08.11.22 um 13:46 schrieb Michael Geddes:
> Ah yes. Arrays - will check those. Yeah, how about we add a
> 'IsDefined' method to metrics instead of the null thing (it does sound
> like it will upset too many applecarts).
>
> //.
>
> On Tue, 8 Nov 2022 at 20:35, Michael Balzer <dexter at expeedo.de> wrote:
>
> Michael,
>
> looks all good to me, once again nice find with the decode
> argument. Adding decode to the Value() call was only for symmetry
> IIRC, the main use was with GetValues()
> (https://docs.openvehicles.com/en/latest/userguide/scripting.html#ovmsmetrics).
>
> Don't forget to test arrays, e.g. "v.t.pressure" & "v.t.temp".
>
> Returning null for an undefined metric seems like a natural
> choice, but is a rather deep change, as for consistency not only
> the Duktape metrics API but also the Web UI metrics API would need
> to be changed accordingly. Unless you've got a real use case that
> needs that, we should be careful.
>
> Regards,
> Michael
>
>
> Am 07.11.22 um 15:00 schrieb Michael Geddes:
>> I have figured out a bunch of stuff and have implemented the
>> following: (having done away with needing AsFloatUnit)
>>
>> OvmsMetrics.Value( {metric} [, {decode}])
>> OvmsMetrics.Value( {metric}, {unit} [,{decode}])
>>
>> It turns out that the [decode] flag wasn't working anyway (since
>> the function was being registered as only having 1 param)...
>> This way it is still really 1 function.. but I check it the
>> second parameter is a 'boolean', and if not.. try the second form.
>>
>> OvmsMetrics.AsFloat( {metric} [,{unit}] )
>>
>> and add the function
>>
>> Ovms.Metrics.ValueUnit( {metric} [,{unit}])
>> This prints the value and the unit.
>>
>> Here's a sample function and the output! This also shows the
>> types of the output.
>>
>> (function() {
>> x = OvmsMetrics.Value("xiq.v.trip.consumption");
>> print( (typeof x) + ": "+ x+"\n" );
>> x = OvmsMetrics.Value("xiq.v.trip.consumption", false);
>> print( (typeof x) + ": "+ x +"\n" );
>> x = OvmsMetrics.Value("xiq.v.trip.consumption","kmpkwh")
>> print( (typeof x) + ": "+ x +"\n");
>> x = OvmsMetrics.Value("xiq.v.trip.consumption", "mipkwh", false)
>> print( (typeof x) + ": "+ x +"\n");
>> x = OvmsMetrics.ValueUnit("xiq.v.trip.consumption")
>> print( (typeof x) + ": "+ x +"\n");
>> x = OvmsMetrics.ValueUnit("xiq.v.trip.consumption","mipkwh")
>> print( (typeof x) + ": "+ x +"\n");
>> x = OvmsMetrics.AsFloat("xiq.v.trip.consumption")
>> print( (typeof x) + ": "+ x +"\n");
>> x = OvmsMetrics.AsFloat("xiq.v.trip.consumption","kmpkwh")
>> print( (typeof x) + ": "+ x +"\n");
>> })();
>>
>> number: 17.0582
>> string: 17.0582
>> number: 5.86227
>> string: 3.64264
>> string: 17.0582kWh/100km
>> string: 3.64264mi/kWh
>> number: 17.0582
>> number: 5.86227
>>
>>
>> It still might be an idea to use 'null' as a return value if the
>> metrics is!IsDefined() but that would be changing the existing
>> behaviour slightly.
>>
>> //.ichael
>>
>> On Mon, 7 Nov 2022 at 08:12, Michael Geddes
>> <frog at bunyip.wheelycreek.net> wrote:
>>
>> I've worked out what the decode flag is for and how it works,
>> and I think how optional params work.
>> I'm pretty sure I won't need the 'AsFloatUnit' function; the
>> unit would be an option to AsFloat(); I'll know that soon.
>>
>> The 'Value' function is more complicated because of the
>> optional decode bool. I guess I could add the Unit to the end
>> of that.
>>
>> ValueUnit could be still useful then to provide a 'Value + Unit'.
>>
>> Question: Is there a reason we shouldn't be returning with
>> duk_push_null if the metric !IsDefined() in both AsFloat()
>> and Value(metric,true) cases?
>>
>> //.ichael
>>
>> On Sun, 6 Nov 2022 at 11:22, Michael Geddes
>> <frog at bunyip.wheelycreek.net> wrote:
>>
>> Right, so I've implemented some stuff that seems to work
>> quite well.
>>
>> https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/pull/764
>> should be ready now after a couple of stupid mistakes
>> slipped through. This absolutely needs somebody to
>> review it please! (There's a reason why I've converted
>> some if()'s to switch() - which is that it will be used
>> in the follow-up commit).
>>
>> The commit that will follow on from that it implements
>> the new Units: kWh/100km, km/kWh and mi/kWh.
>>
>> This is a summary of what I've implemented for scripting
>> - including showing the unit codes I have so far. I've
>> considered a few things:
>> * Should some of the longer unit codes be shortened
>> (eg mi, mins, m, ft, deg, perc)
>> * The unit codes could be much more regular and
>> separated by dots eg:
>> watthours -> w.h
>> kwhp100km -> kw.h_100km or kw.h/100km
>> miph -> mi_h or mi/h (or should it be mph).
>> psi -> p_in.in <http://p_in.in> or p/in.in <http://in.in>
>> or lb_in.in <http://lb_in.in> (yes, slightly weird, but
>> predictable)
>>
>> *OVMS# metric units*
>> km : km
>> miles : M
>> meters : m
>> feet : ft
>> celcius : °C
>> fahrenheit : °F
>> kpa : kPa
>> pa : Pa
>> psi : psi
>> volts : V
>> amps : A
>> amphours: Ah
>> kw : kW
>> kwh : kWh
>> watts : W
>> watthours: Wh
>> seconds : Sec
>> minutes : Min
>> hours : Hour
>> utc : UTC
>> degrees : °
>> kmph : km/h
>> miph: Mph
>> kmphps: km/h/s
>> miphps: Mph/s
>> mpss : m/s²
>> dbm : dBm
>> sq : sq
>> percent : %
>> whpkm : Wh/km
>> whpmi: Wh/mi
>> kwhp100km : kWh/100km
>> kmpkwh: km/kWh
>> mipkwh: mi/kWh
>> nm : Nm
>>
>> *OVMS# metric unit mi*
>> miles : M
>> minutes : Min
>> miph : Mph
>> miphps : Mph/s
>> whpmi : Wh/mi
>> mipkwh : mi/kWh
>>
>> *OVMS# metric get xiq.v.trip.consumption
>> *17.0597kWh/100km
>> *OVMS# metric get xiq.v.trip.consumption kpkwh
>> *5.86177km/kWh
>> *OVMS# metric get xiq.v.trip.consumption mpkwh
>> *3.64233mi/kWh
>>
>> *OVMS# metric set xiq.c.speed 5 miph
>> *Metric set
>> *OVMS# metric get xiq.c.speed
>> *8.04673km/h
>> *OVMS# metric get xiq.c.speed miph
>> *5Mph
>>
>> And then in DukTape - there are some questions I have
>> about the implementation:
>> * Names of functions? Better ideas?
>> * Should ValueUnit output the units?
>> * In Value() there is the line bool decode =
>> duk_opt_boolean(ctx, 1, true);
>> * What does 'decode' mean here?
>> * Do I need it for ValueUnit() ?
>>
>> *
>> (function() {
>> print( OvmsMetrics.Value("xiq.v.trip.consumption"));
>> print("\n")
>> print(
>> OvmsMetrics.ValueUnit("xiq.v.trip.consumption",""));
>> print("\n")
>> print(
>> OvmsMetrics.ValueUnit("xiq.v.trip.consumption","mipkwh"));
>> print("\n")
>>
>> print(
>> OvmsMetrics.AsFloatUnit("xiq.v.trip.consumption","kmpkwh"));
>> })();*
>> --- Output ---
>> 17.0597
>> 17.0597kWh/100km
>> 3.64233mi/kWh
>> 5.86177
>> ------
>>
>> The basic stuff all works - it's just quibbling over the
>> details.. but let's get them right!
>>
>> //.ichael
>>
>> On Sat, 5 Nov 2022 at 20:09, Michael Geddes
>> <frog at bunyip.wheelycreek.net> wrote:
>>
>> Yeah - this was copied code from kia/kona and is what
>> triggered these ideas; I totally agree this shouldn't
>> be doubled up on.
>>
>> I've got some commits centred round Metrics that I'll
>> just check over and push up ... and then I'll just
>> have the single xiq.v.trip.consumption metric (unless
>> you have some ideas for the namespace) which will be
>> much neater.
>>
>> If it's ok with you then I might do that unit
>> conversion proposal.
>> Would it ok if the unit specifications were the same
>> as to the programatic codes in ovms_metrics.h?
>> (kWh, WattHours , MetersPSS )
>> I would probably add a command
>> metric units <spec>
>> to list all (matching) units and their associated Labels.
>>
>> //.ichael
>>
>> On Sat, 5 Nov 2022 at 18:48, Michael Balzer
>> <dexter at expeedo.de> wrote:
>>
>> Michael,
>>
>> adding unit conversion support to the shell and
>> Duktape commands is a good idea.
>>
>> Metrics are not meant to provide a user
>> interface, they should be defined to be efficient
>> and non-redundant.
>>
>> Btw, metrics names also shall not use upper case
>> characters, and shall only use "." as a separator.
>>
>> Regards,
>> Michael
>>
>>
>> Am 05.11.22 um 11:22 schrieb Michael Geddes:
>>> Hi all,
>>> Some of the code I copied from Kona/Kia code had
>>> both kwh/100km and km/kwh metrics in the code as
>>> 'Other'.
>>> Adding the various power consumption Units is
>>> not particularly hard (I will have a
>>> pull-request soon) - though the conversions
>>> between them all required some thought!
>>> ... but it also made me think these two metrics
>>> that are (with the consumption units added)
>>> defined like this:
>>> m_v_trip_consumption1 =
>>> MyMetrics.InitFloat("xiq.v.trip.consumption.KWh/100km",
>>> 10, 0, kWHP100K);
>>> m_v_trip_consumption2 =
>>> MyMetrics.InitFloat("xiq.v.trip.consumption.km/kWh
>>> <http://xiq.v.trip.consumption.km/kWh>", 10, 0,
>>> kPkWH);
>>>
>>> These are effectively the same metric but in
>>> different units!
>>> I'm wondering if we would be better to have
>>> scripting and Duktape support for converting
>>> metrics to different unit! This might be also
>>> quite useful for those strange countries that
>>> insist on using miles as a measurement.
>>>
>>> On top of the 'metric list' and 'metric set' we
>>> could add a 'metric get' which gets a single
>>> value.. and add unit support for get/set.
>>>
>>> I've also got a pull request that improves the
>>> precision of the km<->mi conversions and factors
>>> it out.
>>>
>>> //.ichael
>>>
>>> _______________________________________________
>>> OvmsDev mailing list
>>> OvmsDev at lists.openvehicles.com
>>> http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>
>> --
>> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
>> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
>>
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>>
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>
> --
> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
>
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--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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