% Simulate a digital controller
% Plant = Gs
% Controller = K
% Sampling Rate = T

Gs = zpk([],[-1,-5,-10],200);
T = 0.5;
dt = T/100

Gs_ABCD = ss(Gs);
K = 0.7;
A = Gs_ABCD.A;
B = Gs_ABCD.B;
C = Gs_ABCD.C;
D = Gs_ABCD.D;

A = expm(A*dt);
B = B*dt;
N = length(B);

Data = [];
X = zeros(N,1);

Y = 0;
R = 1;
t = 0;

while(t < 9.9)
   if(mod(t,T) < dt)
       U = K*(R - Y);
       end

    X = A*X + B*U;
    Y = C*X + D*U;
   
    t = t + dt;  
    
    Data = [Data ; [Y, U, R]];
end

t = [0:length(Data)-1]' * dt;
plot(t, Data)
xlabel('Time (seconds)')