The default sample times of Simscape™ blocks are continuous. You cannot simulate Simscape blocks with discrete solvers using the default sample times.
If you switch to a local solver in the Solver Configuration block, the states of the associated physical network become discrete. If there are no continuous Simulink® or Simscape states anywhere in a model, you are free to use a discrete solver to simulate the model.
You cannot override the sample time of a nonvirtual subsystem containing Simscape blocks.
A Simscape physical network should not exist within a Simulink algebraic loop. This means that you should not directly connect an output of a PS-Simulink Converter block to an input of a Simulink-PS Converter block of the same physical network.
For example, the following model contains a direct feedthrough between the PS-Simulink Converter block and the Simulink-PS Converter block (highlighted in magenta). To avoid the algebraic loop, you can insert a Transfer Function block anywhere along the highlighted loop.
A better way to avoid an algebraic loop without introducing additional dynamics is shown in the modified model below.
Certain Simulink tools and features do not work with Simscape software:
Exporting a model to a format used by an earlier version (Simulation > Save > Previous Version) is not supported for models containing Simscape blocks.
The Simulink Profiler tool does not work with Simscape models.
Physical signals and physical connection lines between conserving ports are different from Simulink signals. Therefore, the Viewers and Generators Manager tool and the signal label functionality are not supported.
Certain Simulink tools are restricted for use with Simscape software:
You can use the Simulink
get_param commands to set or
get Simscape block parameters, if the parameters correspond to fields in the
block dialog box. It is not recommended that you use these commands to find or
change any other block parameters.
If you make changes to block parameters at the command line, run your model
first before saving it. Otherwise, you might save invalid block parameters. Any
block parameter changes that you make with
set_param are not validated
unless you run the model.
Simscape blocks accept
Simulink.Parameter objects as
parameter values in
set_param, within the restrictions specified
Enabled subsystems can contain Simscape blocks. Always set the States when enabling
parameter in the Enable dialog to
held for the subsystem's
Setting States when enabling to
is not supported and can lead to fatal simulation errors.
You can place Simscape blocks within nonvirtual subsystems that support continuous states. Nonvirtual subsystems that support continuous states include Enabled subsystems and Atomic subsystems. However, physical connections and physical signals must not cross nonvirtual boundaries. When placing Simscape blocks in a nonvirtual subsystem, make sure to place all blocks belonging to a given Physical Network in the same nonvirtual subsystem.
Nonvirtual subsystems that do not support continuous sample time blocks (such as If Action, For Iterator, Function-Call, Triggered, While Iterator, and so on) cannot contain Simscape blocks.
An atomic subsystem with a user-specified (noninherited) sample time cannot contain Simscape blocks.
Simulink configurable subsystems work with Simscape blocks only if all of the block choices have consistent port signatures.
When using Simulink operating points to save and restore simulations of models, you
cannot make any changes to the Simscape blocks in the model between the time at which you save the
ModelOperatingPoint object and the time at which you
restore the simulation using the
For more information, see Limitations of Saving and Restoring Operating Point.
This is an extension of the Simulink limitation prohibiting structural changes to the model between
these two points in time. Changes to Simscape block parameters can cause equation changes and result in changes
to the state representation. Therefore, modifying parameters of Simscape blocks between saving and restoring the
SimState is not allowed.
Instead of using Simulink operating points, you can use Simscape operating points to initialize models containing Simscape blocks. For more information, see Using Operating Point Data for Model Initialization.
Linearization with the Simulink
linmod function or with
Control Design™ functions and graphical interfaces is not supported with
Simscape models if you use local solvers.
Model referencing is supported, with some restrictions:
All Physical connection lines must be contained within the referenced model. Such lines cannot cross the boundary of the referenced model subsystem in the referencing model.
The referencing model and the referenced model must use the same solver.
You cannot create Simulink signal objects directly on the PS-Simulink Converter block outputs. Insert a Signal Conversion block after the output port of a PS-Simulink Converter block and specify the signal object on the output of the Signal Conversion block instead.
Simscape run-time parameters are run-to-run tunable. Therefore, for Dashboard blocks linked to Simscape blocks, changing the dials during simulation does not affect the simulation results.
To use Dashboard blocks for run-to-run tuning of Simscape block parameters, designate the parameter as
Run-time configurable, associate it with a
workspace variable, and link the Dashboard block to the workspace variable. For
more information, see About Simscape Run-Time Parameters .
Some Simulink tools and features do not work with Simscape blocks:
Execution order tags do not appear on Simscape blocks.
Simscape blocks do not invoke user-defined callbacks.
You cannot set breakpoints on Simscape blocks.
Reusable subsystems cannot contain Simscape blocks.
You cannot use the Simulink Fixed-Point Tool with Simscape blocks.
The Report Generator reports Simscape block properties incompletely.
Code generation is supported for Simscape physical modeling software and its family of add-on products. However, there are restrictions on code generated from Simscape models.
Code reuse is not supported.
Encapsulated C++ code generation is not supported.
Tunable parameters are not supported.
Run-time parameter inlining ignores global exceptions.
MaxStackSize is not supported.
Simulation of Simscape models on fixed-point processors is not supported.
Block diagnostics in error messages are not supported. This means that if you get an error message from simulating generated code, it does not contain a list of blocks involved.
Conversion of models or subsystems containing Simscape blocks to S-functions is not supported.
There are variations and exceptions as well in the code generation features of the add-on products based on Simscape platform. For details, see documentation for individual add-on products.
Most code generation options for Simscape models require the use of fixed-step Simulink solvers. This table summarizes the available solver choices, depending on how you generate code.
|Code Generation Option||Solver Choices|
Rapid Accelerator mode
|Variable-step or fixed-step|
|Simulink Coder™ software: RSim Target*||Variable-step or fixed-step|
|Simulink Coder software: Targets other than RSim||Fixed-step only|
* For the RSim Target, Simscape software supports only the Simulink solver module. In the model Configuration Parameters dialog box, see the Code Generation: RSim Target: Solver selection menu. The default is automatic selection, which might fail to choose the Simulink solver module.