Simultaneous Equations Using MATLAB Function Block in Simulink

Hi all,

I suspect this may be a very basic question, however I am very new to the software and am trying my best to battle through by trial and error and helpful advice found on this website.

I have three equations containing three unknown. This is how I have inputted into the MATLAB workspace inside the MATLAB function block of Simulink:

function [qdot,Tpo,Tso] = fcn(mdotp,Cpp,Tpi,mdots,Cps,Tsi,U,A,f)
%#codegen

qdot = U*A*f*((Tpo-Tso)-(Tpi-Tsi))/log((Tpo-Tso)/(Tpi-Tsi))
qdot = mdotp*Cpp*(Tpi-Tpo)
qdot = mdots*Cps*(Tso-Tsi)

Where; qdot, Tpo, Tso are the unknowns I want as outputs from the Simulink block

and; mdotp, Cpp, Tpi, mdots, Cps, Tsi, U, A, f are known input into the Simulink block

Unfortunately when I run the simulation, a whole host of error is spewed out.

I would be forever grateful if someone can help me. Very much left scratching my head!

Regards Andy

Answer 1

[TAB]

1. Tpo and Tso are used for calculating qdot without defining and initializing them first.
2. Tpo and Tso are outputs from the function but they are never returned.From the program it seems that you are treating then as input.
3. Also you are overwritting qdot in 3 statements. (It may generate warning).