Units
EDCS adopts the ISO 31 International System of Units (SI)
Ref: http://physics.nist.gov/cuu/Units/index.html
- The SI is founded on seven base units for seven base quantities assumed to be mutually independent.
- Other quantities, called derived quantities, are defined in terms of the seven base quantities via a system of quantity equations. The derived units for these derived quantities are obtained from these equations and the seven base units.
- The radian and steradian are supplemental units which are now interpreted as so-called dimensionless derived units, and they may be used in expressions for derived units.
- SI base, derived, and supplemental units may be combined with standard prefixes, or scales.
- Certain units are not part of the International System of Units; that is, they are outside the SI, but are important and widely used. Units in this category are accepted for use with the SI, and in the EDCS Standard e.g., ARC_MINUTE, HOUR, LITRE.
- Other units outside the SI are currently accepted for use with the SI by NIST. Their continued use is not encouraged. Units in this category which are accepted for use with the SI in the EDCS are referred to as deprecated units. They will be removed from a future release of the EDCS Standard; e.g., MILE, TON.