Parameters, variables, and physical signals can have units associated with them. You specify the units along with the parameter values in the block dialogs, and Simscape™ unit manager performs the necessary unit conversion operations when solving a physical network. Simscape blocks support standard measurement systems. The default block units are meter-kilogram-second or MKS (SI).
Simscape software comes with a library of standard units, and you can define additional units as needed (see Unit Definitions). You can use these units in your block diagrams:
To specify the units of an input physical
signal, type a unit name, or a mathematical
expression with unit names, in the Input
signal unit field of the Simulink-PS
Converter block dialog. You can also
select a unit from a drop-down list, which is
prepopulated with some common input units. Signal
units that you specify in a Simulink-PS Converter
block must match the input type expected by the
Simscape block connected to it. For example,
when you provide the input signal for an Ideal
Angular Velocity Source block, specify angular
velocity units, such as rad/s
or rpm, in the Simulink-PS
Converter block, or leave it unitless. If you
leave the block unitless, with the Input
signal unit parameter set to
1, then the physical signal
units are inferred from the destination
block.
Simscape block dialogs have drop-down combo
boxes of units next to a parameter value, letting
you either select a unit from the drop-down list,
or type a unit name (or a mathematical expression
with unit names) directly into the box. These
drop-down lists are automatically populated by
those units that are commensurate with the unit of
the parameter, based on the current list of unit
definitions. For example, if a parameter is
specified, by default, with the units of meters
per second, m/s, the drop-down
list of units contains commensurate units, such as
mm/s, in/s,
fps (feet per second),
fpm (feet per minute), and so
on, including any other linear velocity units
currently defined in your unit registry.
To specify the units of an output physical
signal, type a unit name, or a mathematical
expression with unit names, in the
Output signal unit field of
the PS-Simulink
Converter block dialog. You can also
select a unit from a drop-down list, which is
prepopulated with some common output units. The
system compares the units you specified with the
actual units of the input physical signal coming
into the converter block and applies a gain equal
to the conversion factor before outputting the
Simulink® signal. The default value is
1, which means that the unit is
not specified. If you do not specify a unit, or if
the unit matches the actual units of the input
physical signal, no gain is applied.
For more information, see How to Specify Units in Block Dialogs.