Units error (or incompatibiity?) in VehicleInterfaces\Engines\MinimalEngine.mo: r/min vs 1/min about vehicleinterfaces

[tobolar]

Actually, IMO any common variant of revolutions per minute shall be possible: rpm, r/min, rev/min, see Modelica.Units.NonSI.AngularVelocity_rpm (or https://github.com/modelica/ModelicaStandardLibrary/blob/f095aa0350758431efcc9ff65b436c371de9b1ab/Modelica/Units.mo#L1199).
It seems to me being a tool problem. @sjoelund ?

[simonpickering]

@tobolar I'm sure your guess is significantly better than mine as today is the first time I've ever tried to use Modelica "in anger"! :)

I am curious though if you don't mind my asking what may be a basic follow-up question or two (and which aren't directly related to VehicleInterface)?:

I assume that the end of the line you linked to ("Angular velocity in revolutions per minute. Alias unit names that are outside of the SI system: rpm, r/min, rev/min") is an annotation/help entry rather than a definition (which I guess is the unit="rev/min" bit?)

That line does appear in the library in my installation fwiw. I did also do some Googling to try to work out how aliases are defined (and found some documentation on the Maplesoft website which looks very similar but uses "1/min" rather than "rev/min" as the eventual unit for Modelica.Units.NonSI.AngularVelocity_rpm (so that's what I tried.)

Is there somewhere else/some other way that aliases for a given unit are defined? e.g. is "rev" defined somewhere on its own with "r" as an alias?

I'm also a little surprised in hindsight that 1/min (which I used and it seemed to work) can be converted to rad/s which is the native AngularSpeed unit that the engine module expects (I think).

All an interesting learning experience :)

[tobolar]

I assume that the end of the line you linked to ("Angular velocity in revolutions per minute. Alias unit names that are outside of the SI system: rpm, r/min, rev/min") is an annotation/help entry rather than a definition (which I guess is the unit="rev/min" bit?)

Yes. Stating this in MSL makes an impression to me this shall be applicable in any tool. But I don't know if this is the case.

Is there somewhere else/some other way that aliases for a given unit are defined?

As long as I know is this tool specific (e.g. displayunit.mos in Dymola). To be sure, in the case of rpm I would rather use "rev/min" as this is obvious. "1/min" could be, in general, misinterpreted. I will change it in VehicleInterfaces.

You can find some discussion on it here: https://stackoverflow.com/questions/24776407/teaching-modelica-medical-non-si-units