Specialized Administration > Tailoring Business Objects > Type and Attribute Management > Working with the Type and Attribute Management Utility > About Windchill Units > Supported Unit Strings
  
Supported Unit Strings
This topic provides the supported unit strings that are valid when creating measurement systems, quantities of measure, and attributes for types.
Valid Syntax for Supported Unit Strings
The following table provides the syntax for composing a supported unit string. The Syntax column lists the possible syntax and the Legal Values column provides the valid values for each syntax. The following list of topics contain base units, pure units, and unit prefixes which are used in various combinations to build many of the syntax examples shown in the following table:
• Windchill Pure Units
• Base Measures and Units
• Exponential Units Prefixes
The Examples of Supported Unit Strings table provides literal examples used to form a supported unit string. A list of the base units which are the basis for all convertible units can be found in Base Measures and Units.
* 
The following table uses <> (angle brackets) to note the possible syntax that is user-defined with the values shown in the Legal Values column.
Syntax for Building a Supported Unit String
Syntax
Legal Values
<compound_unit>
• <known_compound_unit>
• <unknown_compound_unit>
• (<compound_unit>)
• <compound_unit><integer_power>
• <compound_unit><operation><compound_unit>
<integer_power>
• ** int
• ^ int
<real_power>
• ** real
^ real
<operation>
• *
• /
<pure_unit>
• any symbol from the Pure Units Table
<base_unit>
• any symbol from the Base Units Table
<unit_prefix>
• any symbol from the Unit Prefix Table
<known_unit>
• <pure_unit>
• <unit_prefix> <pure_unit>
<known_compound_unit>
• <known _unit>
• (<known_compound_unit>)
• <known_compound_unit><integer_power>
• <known_compound_unit><operation><known_compound_unit>
<unknown_unit>
• any symbol that is not a <known_unit>
<unknown_compound_unit>
• <unknown_unit>
• <known_compound_unit><real_power>
• <unknown_compound_unit><real_power>
<base_compound_unit>
• <base_unit>
• <base_unit><integer_power> (where base_unit index is greater than 0, and integer_power is greater than 0)
• <base_compound_unit><operation><base_unit> (where base_unit index is greater than all base_unit indices within base_compound_unit)
Units Operator Precedence
Use the following table to determine the priority in which the mathematical operational functions are to be used within supported units strings.
Operator
Description
Precedence
()
parenthesis
1
**
power
2
^
power
2
*
multiply
3
/
divide
3
Examples of Supported Unit Strings
The set of supported unit strings is the union of all convertible unit strings and non-convertible unit strings. The units shown in the Examples column for Base Unit strings and Convertible Unit strings are combinations from the list of Pure Units.
The following table provides examples of supported unit strings:
Examples of Supported Unit Strings
Supported Unit String:
Examples:
Definition
Base Unit strings:
• kg*m/s**2
• cd/m**2
Base unit strings are all <base_compound_unit> strings.
All base unit strings are convertible units strings.
Convertible Unit strings:
• kg*m/s**2
• A**2/kg/m**2*s**4
• 1/um
• oz/s
• (N*m)**-3
Convertible unit strings are all <known_compound_unit> strings.
Non-convertible Unit strings:
• foo
• foo**1.4
• W**0.5
Non-convertible unit strings are all <unknown_compound_unit> strings.
The sets of convertible units strings and non-convertible units strings have no intersection.