S函数模板

function [sys,x0,str,ts] = abs(t,x,u,flag)
%MIXEDM An example integrator followed by unit delay M-file S-function
% Example M-file S-function implementing a hybrid system consisting
% of a continuous integrator (1/s) in series with a unit delay (1/z).
%
% See sfuntmpl.m for a general S-function template.
%
% See also SFUNTMPL.

% Copyright 1990-2007 The MathWorks, Inc.
% $Revision: 1.28.2.1 $


% Sampling period and offset for unit delay.


switch flag

%%%%%%%%%%%%%%%%%%
% Initialization %
%%%%%%%%%%%%%%%%%%
case 0
[sys,x0,str,ts]=mdlInitializeSizes;

%%%%%%%%%%%%%%%
% Derivatives %
%%%%%%%%%%%%%%%
case 1
sys=mdlDerivatives(t,x,u);

%%%%%%%%%%
% Update %
%%%%%%%%%%
case 2,
sys=[];

%%%%%%%%%%
% Output %
%%%%%%%%%%
case 3
sys=mdlOutputs(t,x,u);

%%%%%%%%%%%%%
% Terminate %
%%%%%%%%%%%%%
case 9
sys = []; % do nothing

otherwise
DAStudio.error('Simulink:blocks:unhandledFlag', num2str(flag));

end

% end mixedm

%
%=============================================================================
% mdlInitializeSizes
% Return the sizes, initial conditions, and sample times for the S-function.
%=============================================================================
%
function [sys,x0,str,ts]=mdlInitializeSizes

sizes = simsizes;
sizes.NumContStates = 0;
sizes.NumDiscStates = 0;
sizes.NumOutputs = 1;
sizes.NumInputs = 1;
sizes.DirFeedthrough = 1;
sizes.NumSampleTimes = 1;

sys = simsizes(sizes);
x0 = [];
str = [];
ts = [0 0];

% end mdlInitializeSizes

%
%=============================================================================
% mdlDerivatives
% Compute derivatives for continuous states.
%=============================================================================
%
function sys=mdlDerivatives(t,x,u)

sys = 2;

% end mdlDerivatives

%
%=============================================================================
% mdlUpdate
% Handle discrete state updates, sample time hits, and major time step
% requirements.
%=============================================================================
%


% end mdlUpdate

%
%=============================================================================
% mdlOutputs
% Return the output vector for the S-function
%=============================================================================
%
function sys=mdlOutputs(t,x,u)

% Return output of the unit delay if we have a
% sample hit within a tolerance of 1e-8. If we
% don't have a sample hit then return [] indicating
% that the output shouldn't change.

sys =2* u;


% end mdlOutputs