/UNITS

/UNITS, Label, LENFACT, MASSFACT, TIMEFACT, TEMPFACT, TOFFST, CHARGEFACT, FORCEFACT, HEATFACT
Annotates the database with the system of units used.

DATABASE: Set Up

Label

Label to denote the system of units used in this job:

USER	—	User-defined system (default).
SI	—	International system (m, kg, s, K).
MKS	—	MKS system (m, kg, s, °C).
uMKS	—	μMKS system (μm, kg, s, °C).
CGS	—	CGS system (cm, g, s, °C).
MPA	—	MPA system (mm, Mg, s, °C).
BFT	—	U. S. Customary system using feet (ft, slug, s, °F).
BIN	—	U. S. Customary system using inches (in, lbf*s²/in, s, °F).

If Label = USER, the remaining fields on this command may be used to enter conversion factors that are appropriate for the user-defined system of units.

*`LENFACT`*	—	Conversion factor to meter (m). Default = 1.
*`MASSFACT`*	—	Conversion factor to kilogram (kg). Default = 1.
*`TIMEFACT`*	—	Conversion factor to second (s). Default = 1.
*`TEMPFACT`*	—	Conversion factor to kelvin (K). Default = 1.
*`TOFFST`*	—	Temperature offset from absolute zero in kelvin. Default = 0.
*`CHARGEFACT`*	—	Conversion factor to coulomb. Default = 1.
*`FORCEFACT`*	—	Conversion factor to newton (N). Default = 1.
*`HEATFACT`*	—	Conversion factor to joule (J). Default = 1.

Command Default

User-defined units.

Notes

Allows the user to set a marker in the database indicating the system of units used. The setting may be reviewed with the /STATUS command at the Begin level. The units label and conversion factors on this command are for user convenience only and have no effect on the analysis or data. That is, /UNITS will not convert database items from one system to another (for example, from U. S. Customary to SI, etc.). The units setting will be written to the file of IGES data [IGESOUT or CDWRITE], which can then be read by many programs that read IGES files. The user must still use consistent units for the results to be valid.

If you choose the MKS system of units, the EPZRO option for the EMUNIT command is set to 8.85 e-12 F/m. (EPZRO specifies alternate free-space permittivity.)

For micro-electromechanical systems (MEMS), where dimensions are on the order of microns, see the conversion factors in System of Units in the Coupled-Field Analysis Guide.

If you use the Mechanical APDL ADAMS Interface to export model information to the ADAMS program, the /UNITS command is required to ensure the correct transfer of data between Mechanical APDL and ADAMS. You can choose a predefined unit system label (Label = SI, CGS, etc.) or you can select the user-defined system option (Label = USER) and input the appropriate conversion factors (LENFACT, MASSFACT, TIMEFACT, and FORCEFACT). The conversion factors are written to the ADAMS input file Jobname.MNF to correctly generate the load. For more information, see Export to ADAMS.

All differences between the base solution units used by the Mechanical APDL and CFX solvers are noted in the Mechanical APDL output file. Unit conversions are applied automatically to all loads transferred unless Label = USER. Unit conversions are not applied to any of the loads transferred between the Mechanical APDL and CFX solvers if they use a user-defined unit system.

This command is valid in any processor.

Menu Paths

This command cannot be accessed from a menu.