Custom attributes and units

[mbgitmbgit]

Hello,

I am trying to create value types with custom units. I have three different cases:

1. I found millimetre and nanometre in the SI units but not micrometre. How can I create the unit micrometre, possibly with the SI prefix "micro" and the SI unit "metre".
2. A fully custom unit such as "pixels" with the symbol [px] or "counts" with the unit [cts].
3. A combination of different units such as "counts/watt" with a unit [cts/w].

I have been trying different approaches but i never managed to generate a behavior similar to for example a mass value that accepts mass : MassValue = 1 [kg].

Thank you very much for your help.

[AxelRICHARD]

Hello,

Thank you for using SysON.

The easiest way to do that is to import the following textual model into SysON:

package CustomUnits {
	// Custom units, just for example purposes
	private import SI::*;
	private import SIPrefixes::*;
	private import MeasurementReferences::*;
	
	attribute <μm> micrometre : LengthUnit { :>> unitConversion: ConversionByPrefix { :>> prefix = micro; :>> referenceUnit = m; } }

	attribute <px> pixel: LengthUnit;

	attribute <'px/W'> 'pixel per watt' : LengthUnit = px/W;
}

You can put the text above in a text file (with .sysml extension) and then use the "Upload model" action from the Explorer view toolbar to import the sysml text file:

Alternatively, you can use the "New objects from text" menu item on a Package element:

then paste the text into the popup:

Hope it will help you!

Regards,

[mbgitmbgit]

That worked, thank you very much!