This information is part of the Modelica Standard Library maintained by the Modelica Association.

The following conventions are used in package SIunits:

• Modelica quantity names are defined according to the recommendations of ISO 31. Some of these name are rather long, such as "ThermodynamicTemperature". Shorter alias names are defined, e.g., "type Temp_K = ThermodynamicTemperature;".
• Modelica units are defined according to the SI base units without multiples (only exception "kg").
• For some quantities, more convenient units for an engineer are defined as "displayUnit", i.e., the default unit for display purposes (e.g., displayUnit="deg" for quantity="Angle").
• The type name is identical to the quantity name, following the convention of type names.
• All quantity and unit attributes are defined as final in order that they cannot be redefined to another value.
• Similar quantities, such as "Length, Breadth, Height, Thickness, Radius" are defined as the same quantity (here: "Length").
• The ordering of the type declarations in this package follows ISO 31:

    Chapter  1: Space and Time
    Chapter  2: Periodic and Related Phenomena
    Chapter  3: Mechanics
    Chapter  4: Heat
    Chapter  5: Electricity and Magnetism
    Chapter  6: Light and Related Electro-Magnetic Radiations
    Chapter  7: Acoustics
    Chapter  8: Physical Chemistry
    Chapter  9: Atomic and Nuclear Physics
    Chapter 10: Nuclear Reactions and Ionizing Radiations
    Chapter 11: (not defined in ISO 31-1992)
    Chapter 12: Characteristic Numbers
    Chapter 13: Solid State Physics
  

• Conversion functions between SI and non-SI units are available in subpackage Conversions.