[Ovmsdev] New Metric Units

Michael Balzer dexter at expeedo.de
Sat Nov 26 22:42:27 HKT 2022


The metrics subscription scheme is an option, and the auto-subscribe 
feature via a getter is a nice idea. But I wouldn't apply that to 
metrics value conversions and units.

Also we would still need the current set of metrics to be subscribed by 
default, as there are also non Javascript devices (e.g. smart buttons, 
Wifi displays) reading the WebSocket stream.

My thoughts on this so far:

Basically the web UI, as any frontend, should adapt to unit 
configurations seamlessly. The web UI includes many command outputs, 
which already automatically switch units as configured.

For all practical purposes, the web UI needs to interact with users in 
their preferred units. Only some plugins and functions will need certain 
values in metric (native) units for calculations, and these will also 
need a simple way to convert calculation results back to user units for 
displaying. So I think we need to provide the unit configuration and 
value conversion tools in the web framework as well.

Proposal:

a) We provide a config option and a WebSocket command to switch the 
WebSocket metrics transmission mode to user / native units. To keep 
plugin compatibility, the default is 'native'.

b) We introduce a separate units dictionary object containing the user 
units for both metrics and the unit groups in their code & label 
representation. The units dictionary only needs to be sent initially, 
when new metrics are registered, when the metrics mode is changed for 
the current connection, and when some user unit configuration is 
changed, keeping the bandwidth and processing requirements low.

The units dictionary can combine both metrics and group units, as the 
unit group names are fully distinct from the metrics namespace. The 
transport scheme could be:

{ units: {
   "v.p.speed": { code: "kmph", label: "km/h" }, …
   "units.distance": { code: "miles", label: "M" }, …
}

c) In the web framework, accessing units should be as simple as possible 
and avoid throwing exceptions for undefined entries, so we could e.g. 
split these into separate code & label objects:

units["v.p.speed"]          = "km/h"    // consistently accompanies 
metrics["v.p.speed"]
unitcodes["v.p.speed"]     = "kmph"

units["units.distance"] = "M"
unitcodes["units.distance"] = "miles"

…or provide a getter that tests for the key existence and returns an 
object with empty fields as necessary.

With this, all metrics displays can easily be changed to display the 
actual unit labels instead of using fixed strings.

d) To provide value conversion we implement UnitConvert() in Javascript 
plus some wrappers that automatically look up the unit for a given 
metrics/group name and do the conversion to/from native units, something 
like…

var speed_kph    = toNativeValue("v.p.speed");   // optional second arg 
to convert any data
var speed_kph    = metrics_native["v.p.speed"];  // using a getter

var trip_display = toUserValue("units.distance", 1234);


Plugins for scientific/technical applications that depend on native 
(metric) units can use the new metrics transmission mode control command 
to force native mode. Or they can choose to migrate from "metrics[]" to 
"metrics_native[]".

The metrics mode config option can come with a note informing users that 
there may be some old plugins not compatible with non-native units. They 
can then check their plugins for this and make an informed decision on 
wether to enable user units and/or wether to install a specific plugin.

Thoughts, comments?

Regards,
Michael


Am 25.11.22 um 03:13 schrieb Michael Geddes:
> I have an idea which might reduce traffic for maintaining the 
> metrics[] array in the browser and cope with the user units.
> I'll start by saying I'm not a JS developer per se.. so a newb in JS 
> really. Still, it's mainly just another language so .. we'll give it a 
> go.
>
> Firstly:
> * Implement the 'changed' filters as below for the web-socket.. for 
> both normal and 'user' values.
> * Add a function that subscribes to a value (and returns the current 
> value of it)..including to 'user' value/unitlabel.
>
> Subscribing the normal way to the metrics over the websocket would 
> have the normal effect.. but we would have a new way that would 
> subscribe in a filtered way.
>
> I've had a little play with the Proxy object .. so at least I know 
> this should work:
>
> Have a metrics_ array that is the real associative array for metrics[] 
> and then define a Proxy that has (at the least)  'get' and 'has' 
> defined (giving us the ability to overload /metrics['prop']/  and 
> /"prop" in metrics operations/).
>
> The /get /function would return the underlying value if it exists in 
> the /metrics_ /array (which  is maintained through the websocket from 
> currently subscribed values in the current manner).
> If the value is not in the /metrics_/ array - it would then do a 
> subscribe+query on the websocket getting the current value and adding 
> it into the /metrics_/  container. If it was unavailable then it would 
> put /undefined/ into the array.
> The 'has' would do the get() and return true if the value was not == 
> /undefined/.
>
> For the 'query the websocket' bit, I'm assuming I would be working 
> with promises or futures or some such: I'll do the research and do it 
> properly unless somebody can help me out with it. That's the bit I was 
> going to work on next for the proof-of-concept.
>
> Any immediate thoughts? Dangers?
>
> I also noticed there was a bit that went through html element 
> properties and looked for metrics .. this could be used to bulk 
> subscribe to any metric values required there.
>
> //.ichael
>
>
> On Thu, 17 Nov 2022 at 07:52, Michael Geddes 
> <frog at bunyip.wheelycreek.net> wrote:
>
>     Yeah, ok.
>
>     I will get all the other 'user unit' stuff done as a line in the
>     sand, and then move to working out the web stuff.  I'm still
>     finding my way though all the client side javascript, which looks
>     very cool.. but I've not really done jQuery before (just enough to
>     recognise it).
>
>     Subscribing to metrics with/without user units makes a lot of
>     sense.  Obviously the default needs to be 'Subscribe to all
>     metrics but not user units' to maintain compatibility... but I was
>     also thinking it might be nice if we could filter down even the
>     normal subscribed events.
>     We could have:
>     * Web socket command to  filter units (flag on websocket to say
>     'filtered' + flag bitset on each metric  similar to 'dirty')
>     Then either:
>     * Web socket command to turn on user units (single flag on that
>     websocket)
>     or
>     * Web socket command to turn on user units for specific metrics
>     (flag bitset on each metric)
>
>     A parameter to the URI for the websocket could start the socket in
>     'filtered' mode to avoid the initial rush of metrics.
>
>     This could drastically reduce traffic and time for the metrics
>     command to execute.  It would be possible to also check (on a
>     'filtered' websocket) for any changes to metrics for that
>     websocket slot before queueing the 'metric update' socket command.
>
>     //.ichael
>
>
>     On Thu, 17 Nov 2022 at 00:35, Michael Balzer <dexter at expeedo.de>
>     wrote:
>
>         Michael,
>
>         I don't have much spare time currently, just some quick first
>         comments: it's important to implement this as lightweight as
>         possible, both in terms of network load and client CPU &
>         memory requirements. Some devices already have issues, which
>         can be seen by the "websocket overflow" messages. The web UI
>         also should stay usable via cellular.
>
>         My impression is the new scheme, while only slightly raising
>         the client requirements, adds substantially to the network
>         requirements.
>
>         An option could be to separate the units -- or more, back when
>         implementing this I thought about separating the names later
>         on. Another question is if we normally generally need both the
>         native and the converted values in the web UI. We maybe could
>         provide an option to switch to converted values, or add an
>         option to retreive or subscribe to a set of converted metrics
>         on demand.
>
>         Standard plugins like ABRP and PwrMon rely on getting metric
>         (native) units, and there probably are non-public plugins,
>         e.g. for engineering & scientific projects, that depend on
>         metric units to do their calculations and don't need anything
>         else. We shouldn't make life harder for these applications
>         without good reason.
>
>         Regards,
>         Michael
>
>
>         Am 15.11.22 um 01:26 schrieb Michael Geddes:
>>         If you're ok with the [default] option I'll stick with that.
>>         I mean in some ways it would be nice to have a button choice
>>         metric | usa | europe | asia | custom   etc and I kind of
>>         considered something like that but figured it's only a
>>         handful of choices.. and it's an embedded device.. so simpler
>>         is better.
>>
>>         On a related note - I was thinking how it would be nice if
>>         the dashboard (etc) had access to the 'user' units, so went
>>         hunting down that little rabbit hole. Quite a nice mechanism
>>         with the web socket updating the "metrics" object in the UI.
>>         This is a snippet of one idea, which is that for any metric
>>         that has the possibility of a user unit, we set the extra
>>         values of the metric with '#unit' and '#user' appended - see
>>         below. (I've chosen '#' arbitrarily.. but it could be '/' or
>>         ':' or '>'  but maybe not '.' )
>>
>>         v.p.odometer#unit: "M"
>>         v.p.odometer#user: 6754.91
>>         v.p.satcount: 13
>>         v.p.speed: 0
>>         v.p.speed#unit: "km/h"
>>         v.p.speed#user: null
>>         *v.p.trip: 28*
>>         *v.p.trip#unit: "M"
>>         v.p.trip#user: 17.3984*
>>
>>         Then we can use this in the dials to populate the values and
>>         captions! (not that I like Miles).
>>         I
>>
>>         image.png
>>
>>         The other (similar) way was to have something like the following:
>>         "v.p.trip#user" : { "value": 17.3984, "unit": "M" }
>>         It wouldn't make the total message any shorter.. soo.. dunno.
>>
>>         There's also some complications with setting up the dials
>>         (for min/max values) - like for the speed.
>>
>>         Notice also that I'm returning null for undefined values.
>>         It's nice - but I'm not sure how javascript handles null when
>>         used / printed etc.
>>
>>         //.ichael
>>
>>         On Sun, 13 Nov 2022 at 21:06, Michael Balzer
>>         <dexter at expeedo.de> wrote:
>>
>>             Michael,
>>
>>             looks good.
>>
>>             I think having an explicit 'default' option is better
>>             than taking the 'Metric' equivalent for that, as in your
>>             example you already show unit alternatives within the
>>             metric system to support different scalings (kW / W, kWh
>>             / Wh). (Btw… waiting for someone to miss Horsepower & BTU
>>             here ;-))
>>
>>             @Patrick, I think that also answers your implicit question:
>>>             The default button makes it unclear what the actual setting is.
>>
>>             The default (native unit) is always metric, but you may
>>             have a mix of scalings, as we try to find the one that
>>             fits best for the given application when defining a
>>             metric. For example the current driving energy
>>             consumption is stored natively in Wh/km, while the energy
>>             used or regenerated is in kWh, and the odometer & trip
>>             counters are in km, while the altitude ist in m.
>>
>>             Regards,
>>             Michael
>>
>>
>>             Am 13.11.22 um 08:42 schrieb Michael Geddes:
>>>             Greetings,
>>>             so this is my idea of being able to select which units
>>>             various groups use (in addition to Distance).
>>>             This can be then accessed by the special 'user' unit
>>>             code. (or  'metrics list -u ' )
>>>             The idea of [Default] selection below  simply means
>>>             storing the value to blank - meaning use whatever unit
>>>             the particular metric uses.  The other idea I had was to
>>>             actually default it to the equivalent of 'Metric'
>>>             special unit code and not have the [Default] button.
>>>
>>>
>>>             image.png
>>>
>>>             Currently I've made it so that if there are more than 3
>>>             choices other than [default] that it uses the
>>>             choice/combo box rather than the Radio buttons. (ie this
>>>             list is auto-generated from the Metric Units table and
>>>             the Metric Groups table).
>>>
>>>             Thoughts / comments?
>>>
>>>             //.ichael
>>>
>>>             On Sat, 12 Nov 2022 at 17:35, Michael Geddes
>>>             <frog at bunyip.wheelycreek.net> wrote:
>>>
>>>                 https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/pull/771
>>>
>>>                 I'm hoping this P/R is ok in this form (made of 5
>>>                 separate commits).
>>>
>>>                 I will have a look at implementing the "user" unit
>>>                 code.  The base for how it would work is already a
>>>                 part of the above pull request.  I'll just look at
>>>                 the module configuration for distance.
>>>
>>>                 The 'power consumption' is one where it's not just a
>>>                 check-box.. there're 5 possible choice!
>>>
>>>                 I should also add 'bar' for pressure given that for
>>>                 some reason that's still a thing people want.
>>>
>>>                 //.ichael
>>>
>>>                 On Sat, 12 Nov 2022 at 16:24, Michael Balzer
>>>                 <dexter at expeedo.de> wrote:
>>>
>>>                     I think this is pretty decent & complete now.
>>>
>>>                     I also like the approach of the 'user' unit
>>>                     code. Moving all user unit prefs into the module
>>>                     configuration is an old todo. Currently only the
>>>                     distance unit is defined at the module side,
>>>                     temperature and pressure are App prefs.
>>>
>>>                     Regards,
>>>                     Michael
>>>
>>>
>>>                     Am 11.11.22 um 09:54 schrieb Michael Geddes:
>>>>                     Ok - so here's what I have implemented for
>>>>                     Duktape and Metrics. (I added IsDefined() as
>>>>                     well).
>>>>                     Any thoughts on this?
>>>>
>>>>                     Noting
>>>>                      OvmsMetrics.Float( {metric} ) -> Outputs
>>>>                     metric as float (same)
>>>>                      OvmsMetrics.Float( {metric}, {unit}) ->
>>>>                     Outputs metric as float converted to given unit
>>>>                     (new)
>>>>                      OvmsMetrics.Value( {metric} )  -> Outputs
>>>>                     Metric in native value (same)
>>>>                      OvmsMetrics.Value( {metric} , false)   ->
>>>>                     Outputs Metric as string and no units (same)
>>>>                      OvmsMetrics.Value( {metric} , {unit})  ->
>>>>                     Outputs Metric converted to given unit as
>>>>                     native value. (new)
>>>>                     OvmsMetrics.Value( {metric} , {unit}, false ) 
>>>>                     -> Outputs Metric converted to given unit as
>>>>                     string including any unit specifier. (new)
>>>>                     also OvmsMetric.GetValues( {metric} [,{unit}]
>>>>                     [, {converted} ] )  Adds similar behaviour to
>>>>                     Value() above.
>>>>                     also the special units '*imperial*' and
>>>>                     '*metric*' will convert to the associated
>>>>                     imperial / metric version of the units as
>>>>                     appropriate.
>>>>
>>>>                     (function() {
>>>>                        dump = function (metric) { print( metric+ "
>>>>                     ["+(typeof metric)+"]\n"  ); }
>>>>                        dump_obj = function (obj )  {
>>>>                      print('--- Object ----\n')
>>>>                          for (var k in obj) {
>>>>                            xk = obj[k];
>>>>                            print( k+':'+ xk + ' ['+typeof xk+ "]\n");
>>>>                          }
>>>>                        }
>>>>                      dump(OvmsMetrics.Value("xiq.v.trip.consumption"));
>>>>                      dump(OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                     false));
>>>>                      dump(OvmsMetrics.Value("xiq.v.trip.consumption","kmpkwh"));
>>>>                      dump(OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                     "mipkwh", false));
>>>>                      dump(OvmsMetrics.AsFloat("xiq.v.trip.consumption"));
>>>>                      dump(OvmsMetrics.AsFloat("xiq.v.trip.consumption","kmpkwh"));
>>>>                      dump(OvmsMetrics.Value("xiq.v.trip.consumption","imperial"))
>>>>                      dump(OvmsMetrics.Value("xiq.v.trip.consumption","imperial",
>>>>                     false))
>>>>                      dump_obj(OvmsMetrics.GetValues("trip", "metric"))
>>>>                      dump_obj(OvmsMetrics.GetValues("trip",
>>>>                     "imperial", false))
>>>>                     })();
>>>>
>>>>                     With this output:
>>>>                     19.2308 [number]
>>>>                     19.2308 [string]
>>>>                     5.2 [number]
>>>>                     3.23112mi/kWh [string]
>>>>                     19.2308 [number]
>>>>                     5.2 [number]
>>>>                     309.49 [number]
>>>>                     309.49Wh/mi [string]
>>>>                     --- Object ----
>>>>                     v.p.trip:13 [number]
>>>>                     xiq.e.trip:0 [number]
>>>>                     xiq.e.trip.energy.recuperated:0 [number]
>>>>                     xiq.e.trip.energy.used:0 [number]
>>>>                     xiq.v.trip.consumption:19.2308 [number]
>>>>                     --- Object ----
>>>>                     v.p.trip:8.07781M [string]
>>>>                     xiq.e.trip:0M [string]
>>>>                     xiq.e.trip.energy.recuperated:0kWh [string]
>>>>                     xiq.e.trip.energy.used:0kWh [string]
>>>>                     xiq.v.trip.consumption:309.49Wh/mi [string]
>>>>
>>>>                     On Wed, 9 Nov 2022 at 05:47, Michael Geddes
>>>>                     <frog at bunyip.wheelycreek.net> wrote:
>>>>
>>>>                         Yeah - I like HasValue.  I implemented
>>>>                         IsDefined() but I will rename it.. that's a
>>>>                         much clearer name.
>>>>
>>>>                         Another thought. How about if we did this
>>>>                         (but also with GetValues() as well - see
>>>>                         the special values below)
>>>>
>>>>                         OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                          true)  -> 17.0582  (Number)
>>>>                         OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                          false) -> 17.0582  (String)
>>>>                         OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                         "mipkwh", true)  -> 3.64264  (Number)
>>>>                         OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                         "mipkwh", false)  -> 3.64264Mi/kWh  (String)
>>>>                          OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                         "native", false)  -> 17.0582km/kWh  (String)
>>>>
>>>>                         and
>>>>                         OvmsMetrics.Value("xiq.v.trip.consumption",
>>>>                         "imperial", false)  -> 3.64264Mi/kWh  (String)
>>>>
>>>>                         I have already implemented the special
>>>>                         values 'native' (existing), 'imperial' and
>>>>                         'metric'.
>>>>
>>>>                         I was also thinking that in the future you
>>>>                         could have 'user'. Where for each group of
>>>>                         values:
>>>>                         'temperature', 'distance', 'shortdistance',
>>>>                         'power' etc.. you could have a user
>>>>                         preference. I probably won't implement it
>>>>                         now,.but it could be cool that any UI could
>>>>                         just ask for the user defined units (rather
>>>>                         than having a separate choice).
>>>>
>>>>
>>>>
>>>>                         //.ichael
>>>>
>>>>                         On Tue, 8 Nov 2022 at 21:57, Mark
>>>>                         Webb-Johnson <mark at webb-johnson.net> wrote:
>>>>
>>>>                             Or perhaps something more specific?
>>>>
>>>>                                 HasValue()
>>>>
>>>>                             Mark
>>>>
>>>>>                             On 8 Nov 2022, at 9:01 PM, Michael
>>>>>                             Balzer <dexter at expeedo.de> wrote:
>>>>>
>>>>>                             Signed PGP part
>>>>>                             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
>>>>>>>
>>>>>>>                                                 _______________________________________________
>>>>>>>                                                 OvmsDev mailing list
>>>>>>>                                                 OvmsDev at lists.openvehicles.com
>>>>>>>                                                 http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>>>>>>
>>>>>>>
>>>>>>>                                 _______________________________________________
>>>>>>>                                 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
>>>>>>
>>>>>>                                 _______________________________________________
>>>>>>                                 OvmsDev mailing list
>>>>>>                                 OvmsDev at lists.openvehicles.com
>>>>>>                                 http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>>>>>
>>>>>>
>>>>>>                             _______________________________________________
>>>>>>                             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
>>>>>
>>>>
>>>>                             _______________________________________________
>>>>                             OvmsDev mailing list
>>>>                             OvmsDev at lists.openvehicles.com
>>>>                             http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>>>
>>>>
>>>>                     _______________________________________________
>>>>                     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
>>>
>>>                     _______________________________________________
>>>                     OvmsDev mailing list
>>>                     OvmsDev at lists.openvehicles.com
>>>                     http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>>
>>>
>>>             _______________________________________________
>>>             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
>>
>>             _______________________________________________
>>             OvmsDev mailing list
>>             OvmsDev at lists.openvehicles.com
>>             http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>
>>
>>         _______________________________________________
>>         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
>
>         _______________________________________________
>         OvmsDev mailing list
>         OvmsDev at lists.openvehicles.com
>         http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>
>
> _______________________________________________
> OvmsDev mailing list
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> 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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