%% If Block Demonstration
% 
% This demonstration shows what happens when a sine wave is fed into an 
% If block.  After running the simulation, the scope shows three plots.  This 
% demonstration is designed to compare the If block with enabled subsystems.
% 
% The first of these plots shows the original sine wave and the absolute 
% value of the original sine wave offset by two.  The absolute value of the sine
% wave is only shown when the subsystem is executed.  This occurs between
% 0 and 2.5 seconds and 5 and 7.5 seconds.  When the subsystem is not
% executed then the output of the subsystem is reset to 0.  The value of 0 is
% determined by the initial condition of the outport. You can see when 
% the subsysytem is executed by looking at the second plot.  A value of 1 
% indicates that it is executed.
% 
% The second plot shows the original value of the input signal.  If the signal
% is towards the top of the plot then the if subsystem related to the first plot
% is executed.  If the signal is towards the bottom of the plot then the else
% subsystem related to the third plot is executed.  
% 
% The third plot shows the original sine wave and the saturation limited sine 
% wave offset by two.  The saturated value of the sine wave is only shown when 
% the subsystem is executed.  This occurs between 2.5 and 5 seconds and 7.5
% and 10 seconds.
% 
% 

open_system('sldemo_ifsub')