Implementing S-Functions
MATLABS-Functions
Level-2 MATLAB®S-functions allow you to create blocks with many of the features and capabilities of Simulink®built-in blocks, including:
Multiple input and output ports
The ability to accept vector or matrix signals
Support for various signal attributes including data type, complexity, and signal frames
Ability to operate at multiple sample rates
一个2级马TLAB S-function consists of asetup
routine to configure the basic properties of the S-function, and a number of callback methods that the Simulink engine invokes at appropriate times during the simulation.
A basic annotated version of the template resides atmsfuntmpl_basic.m
.
The template consists of a top-levelsetup
function and a set of skeleton local functions, each of which corresponds to a particular callback method. Eachcallback method performs a specific S-function task at a particular point in the simulation. The engine invokes the local functions using function handles defined in thesetup
routine. SeeLevel-2 MATLAB S-Function Callback Methodsfor a table of the supported Level-2 MATLAB S-function callback methods.
A more detailed Level-2 MATLAB S-function template resides atmsfuntmpl.m
.
We recommend that you follow the structure and naming conventions of the templates when creating Level-2 MATLAB S-functions. This makes it easier for others to understand and maintain the MATLAB S-functions that you create. SeeWrite Level-2 MATLAB S-Functionsfor information on creating Level-2 MATLAB S-functions.
墨西哥人S-Functions
Like a Level-2 MATLAB S-function, a MEX S-function consists of a set of callback methods that the Simulink engine invokes to perform various block-related tasks during a simulation. MEX S-functions can be implemented in C, C++, or Fortran. The engine directly invokes MEX S-function routines instead of using function handles as with MATLAB S-functions. Because the engine invokes the functions directly, MEX S-functions must follow standard naming conventions specified by the S-function API.
An annotated C MEX S-function template resides atsfuntmpl_doc.c
.
The template contains skeleton implementations of all the required and optional callback methods that a C MEX S-function can implement.
For a more basic version of the template seesfuntmpl_basic.c
.
MEX VersusMATLABS-Functions
Level-2 MATLAB and MEX S-functions each have advantages. The advantage of Level-2 MATLAB S-functions is speed of development. Developing Level-2 MATLAB S-functions avoids the time consuming compile-link-execute cycle required when developing in a compiled language. Level-2 MATLAB S-functions also have easier access to MATLAB toolbox functions and can utilize the MATLAB Editor/Debugger.
MEX S-functions are more appropriate for integrating legacy code into a Simulink model. For more complicated systems, MEX S-functions may simulate faster than MATLAB S-functions because the Level-2 MATLAB S-function calls the MATLAB execution engine for every callback method.
SeeAvailable S-Function Implementationsfor information on choosing the type of S-function best suited for your application.
See Also
Level-2 MATLAB S-Function|S-Function Builder|S-Function|MATLAB Function|Comparison of Custom Block Functionality