Measurement units measure properties of business applications. These properties comprise physical properties, that can be associated with dimensions in a measurement system, and properties without dimension, that cannot be defined uniquely in a measurement system.
To use electronic data interchange (EDI) you must use the ISO code measurement units. Furthermore, measurement units carry several other names for internal and external presentation in the R/3 system.
Physical Properties
Physical properties are basic or derived. Derived properties are algebraic combinations of basic properties. Which physical properties are viewed as basic and which as derived is a matter of expediency. There are many different measurement systems with different basic properties. Each basic property defines one basic dimension of a measurement system.
The SAP standard shipment uses the international measurement unit system (SI) with the seven basic properties length, time, mass, temperature, electrical current, light intensity, and molarity. The SI-System has seven basic dimensions.
The basic properties of each dimension can be measured in specific measurement units. The measurement units of the seven basic SI system dimensions are meter (m), second (s), kilogram (kg), Kelvin (K), ampere (A), candela (cd) and mol (mol).
The dimensions of all derived properties of a measurement system are algebraic combinations of its basic dimensions. In the SI system, the measurement units of derived properties are combinations of the SI units and some have their own names and abbreviations.
Derived property |
Measurement Unit |
Name |
Speed |
m/s |
--- |
Acceleration |
m/s^{2} |
--- |
Force |
kg m/s^{2} |
Newton (N) |
Energy |
kg m^{2}/s ^{2} |
joule (J) |
You can define any number of other measurement units besides the SI units for each SI system dimension. Different measurement units of one dimension have a linear relationship which allows conversion between them and to the corresponding SI unit.
Dimension |
Measurement Unit |
Conversion to SI Unit |
Length |
inch (") |
0,0254 m |
Mass |
ton (t) |
1000 kg |
Temperature |
Celsius (°C) |
K - 273,14 |
Energy |
erg (erg) |
0.0000001 J |
Such definitions can be more convenient for some purposes (for example centimeters and kilometers) or they are country specific (for example feet and miles).
As the relationships between the dimensions as well as the different measurement units of one dimension are defined uniquely, they are maintained centrally in Customizing tables in the R/3 System. The dimensions of derived properties are defined in these tables by defining the exponents of the underlying basic dimensions. The names of these Customizing tables start with T006. You maintain these tables with the transactions CUNI and OMSC. The function modules described in this section use these tables.
In the R/3 System, combinations of basic dimensions must be unique and can be related to one derived dimension only. For example, energy (force times distance) and torque (force times radius) cannot be defined in one R/3 System simultaneously.
In some applications (e.g. SAP Oil & Gas), the temperature and pressure values for which the measurement units of certain dimensions (e.g. volume).are valid must be specified. The measurement units of such dimensions are maintained as temperature and pressure-dependent. The measurement units for this dimension are then defined for a specified temperature and pressure. This is the case for example for natural gas whose volume depends on the temperature and pressure. A basic measurement unit of the dimension volume in the inventory describes the amount of gas under defined conditions.
Properties without Dimensions
Measurement units for properties without dimensions are important for business applications as well as the measurement units for the seven physical properties of the SI system. These units are used for countable properties. For example palette, box, piece etc. There are no unique relationships between measurement units without dimensions. They depend on the business applications. For example, a box can contain one, six, or twelve pieces.
Conversions between the measurement units without dimensions in the R/3 System are defined material-specifically in the table MARM. You maintain table MARM with transactions MM01 and MM02 in the applications. The function modules described in this section also use this table.
Abbreviations of Measurement Units – ISO Code
The ISO standard 31 describes measurement units. This standard does not prescribe official abbreviations (ISO codes) for the measurement units. Recommendation 20 of WP.4 of the UN/ECE (UN Economic Commission for Europe, Information Office, Palais des Nations, CH-1211 Geneva, phone +4122917 2893, fax +4122917 0036, e-mail info.ece@unece.org, http://www.unicc.org/unece/oes/info.htm) makes recommendations for the ISO codes of measurement units. Since you need the ISO Code for electronic data exchange (EDI), you should maintain the recommended ISO code for each measurement unit in the R/3 System tables.
Internal and External Measurement Unit Formats
Measurement units in the R/3 System have different internal and external formats. The internal presentation is language-independent, is only for internal processing, and does not appear on the interface. The external format is language-dependent appears on screens. The external format has different names for different uses:
commercial |
(three upper-case characters) | |
technical |
(six-character) | |
short text |
(ten-character) | |
long text |
(thirty-character) |
These names types are maintained language-dependently in table T006A. For example, the commercial name of the dimension-less measurement unit piece is PC in English, ST (Stuck) in German, and PI (Piece) in French.
The commercial and technical formats together with the language form a language-dependent key for the corresponding internal format of the measurement unit. Therefore, they must be maintained uniquely for each language.
The system uses the language-dependent key that is defined from the commercial and technical formats in conversion exits. These conversion exits are called automatically in screens and by the WRITE command if the domains of the data elements involved use the conversion exits LUNIT (for technical measurement units) or CUNIT (for commercial measurement units).