function xprime=input_multivessel(t,X) 
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%%%%% Program written by Stathis skouras, May 2001.%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% Number of stages in the top section: 
NT1=25;
% Number of stages in the bottom section (without the reboiler): 
NT2=25;
% Total number of 'stages'  
NT=NT1+NT2+3;  % We include condenser and middle vessel (for practical reasons) and reboiler 

% Inputs
VB=5;                                  % Boilup (kmol/hr)
L0=VB;                                 % Nominal liquid flows in both sections of the column (kmol/hr)

% Controllers gains and setpoints 
Kc1=5;                                 % Controller gain at the top section (Kmol/(hr*C))
tI=1;                                  % Integration time (hr)
Ms=0.0001;                             % Level controller set-point (kmol)

Kc2=0.236;                             % Proportional controller gain at the bottom section (kmol/(hr*C))
Tsp2=90.7;                             % Temperature setpoint in the bottom section (C)

% Precaution so as condenser and middle vessel do not run empty
Hmin=0.001;                            % Minimum liquid holdup in condenser and middle vessel   

% Store all inputs and disturbances
U(1)=VB; U(2)=L0; U(3)=Kc1; U(4)=tI; U(5)=Ms; U(6)=Kc2; U(7)=Tsp2; U(8)=Hmin;
xprime=multivessel(t,X,U);
t