Output argument 'x' is not assigned on some execution paths.

Hello, I wrote the following code in the Matlab function in simulink and the error "Outut argument 'x' is not assigned on some execution paths" occurred. I don't know why the code not working. I hope you can help me. Thank you

My simulink function block have this code:

function [x,y] = fcn(u)
% u = battery voltage
% x=1 battery charge switch
% y=1 battery discharge switch

    if (u<=0.9) % battery charge
        while (u<=1.2)
            x=1;
            y=0;
        end
    elseif (u>1.2) || (u>0.9) && (u<1.2) %battery discharge
        while (u>=0.9)
            x=0;
            y=1;
        end
    else
        x=0;
        y=0;
    end
end

Answer 1

[Ameer Hamza]

Ok. I suspect you are trying to run this code on Simulink in the MATLAB function block. Since you didn't provide this information, so it is difficult to see what the issue is. Simulink use C/C++ code-generation and then compile your model. Therefore, it is necessary to initialize your variables, even if they will get their values later in code execution. Therefore, at the beginning of your function, initialize x, and y

function [x,y] = fcn(u)
% u = battery voltage
% x=1 battery charge switch
% y=1 battery discharge switch

x = 0; % this initialization is necessary for Simulink. Even if this is not goint to be used
y = 0;

% rest of your code

Also, use 'if', instead of while as pointed out by KSSV.

[Serdar GÜNAY]

Yes,the problem was solved.

but,

if (u <= 0.9)% battery charging

if (u <= 1.2)

x = 1;

y = 0;

end

elseif

this condition not working. 1. if is working, 2. if is not working. u initial value <=0.9 , when u is greater than 0.9, y = 1 x = 0.

[Ameer Hamza]

Can you describe your condition in words or write a mathematical equation of what you want to implement here. It seems like there will be an easier way, but I am not able to understand what you are trying to do in these lines.

[Serdar GÜNAY]

If the battery voltage is less than 0.9, it will charge until it reaches 1.2 volts and exit this cycle.

If the battery voltage is between 0.9 and 1.2, it will discharge to 0.9 and return to the initial state by exiting this cycle.

So, for this purpose, the battery will not stay on continuous charge.

x=1 y=0 charge

y=1 x=0 discharge

[Ameer Hamza]

By default, the MATLAB function block does not remember what happened in the previous time-step, so it will not remember whether it needs to charge or discharge of voltage is between 0.9 and 1.2. In that case, we need to use a persistent variable. Try the following code

function [x,y,z] = fcn(u)
    % u = battery voltage
    % x=1 battery charge switch
    % y=1 battery discharge switch
    x = 0;
    y = 0;
    
    persistent state % state=0<=>charging, state=1<=>discharging
    if isempty(state)
        state = 0;
    end
    
    if u <= 0.9
        state = 0;
    elseif u >= 1.2
        state = 1;
    end
    
    if state==0
        x = 1;
        y = 0;
    else
        x = 0;
        y = 1;
    end
    z = state;
end

[Serdar GÜNAY]

I didn't know about this problem in Matlab. Thank you. My problem is solved.

Good work..

[蒙召 张]

Thank you. I have the same problem. Your answer was very useful and solved my problem

[akhongbam]

guys can u help in coding for active cell balancing

this is my code

function [s1,s2,s3,s4,s5,s6,s7,s8,s9,s10,s11,s12,s13,s14] = fcn(soc1,soc2,soc3,soc4,soc5,soc6,soc7,pwm1,pwm2)

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;

s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

high= max([soc1 soc2 soc3 soc4 soc5 soc6 soc7]);

low = min([soc1 soc2 soc3 soc4 soc5 soc6 soc7]);

if high==soc1&&low==soc2

s1=pwm1;s2=1;s5=pwm2;

s3=0;s4=0;s6=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc1&&low==soc3

s1=pwm1;s2=pwm1;s4= pwm2;s7=pwm2;

s3=0;s5=0;s6=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc1&&low==soc4

s1=pwm1;s2=pwm1;s6=pwm2;

s3=0;s4=0;s5=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc1&&low==soc5

s1=pwm1; s4=pwm1; s7= pwm2;s11=pwm2;

s2=0;s3=0;s5=0;s6=0;s8=0;s9=0;s10=0;s12=0;s13=0;s14=0;

elseif high==soc1&&low==soc6

s1=pwm1;s7=pwm1;s10=pwm2;s12=pwm2;

s2=0;s3=0;s4=0;s5=0;s6=0;s8=0;s9=0;s11=0;s13=0;s14=0;

% soc2 starts here

elseif high==soc2&&low==soc1

s3=1;s4=pwm1;

s1=0;s2=0;s5=0;s6=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc2&&low==soc3

s3=pwm1;s5=pwm1;

s1=0;s2=0;s6=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc2&&low==soc4

s3=pwm1;s4=pwm1;s6=pwm2;

s1=0;s2=0;s5=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

%soc3 starts here

elseif high==soc3&&low==soc1

s3=pwm2;s5=pwm1;s6=pwm1;

s1=0;s2=0;s4=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc3&&low==soc2

s2=pwm1;s6=pwm2;s5=1;

s1=0;s3=0;s4=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc3&&low==soc4

s5=pwm1;s6=1;

s1=0;s2=0;s3=0;s4=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc3&&low==soc5

s5=pwm1;s7=pwm1;s9=pwm2;

s1=0;s2=0;s3=0;s4=0;s6=0;s8=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc3&&low==soc6

s5=pwm1;s7=pwm1;s9=pwm2;s11=pwm2;

s1=0;s2=0;s3=0;s4=0;s6=0;s8=0;s10=0;s12=0;s13=0;s14=0;

elseif high==soc3&&low==soc7

s5=pwm1;s7=1;s9=pwm1;s11=pwm2;s13=pwm2;

s1=0;s2=0;s3=0;s4=0;s6=0;s8=0;s10=0;s12=0;s14=0;

%soc4 starts here

elseif high==soc4&&low==soc1

s3=pwm2;s7=pwm1;s8=pwm1;

s1=0;s2=0;s4=0;s5=0;s6=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc4&&low==soc2

s2=pwm2;s5=pwm2;s7=pwm1;s8=pwm1;

s1=0;s3=0;s4=0;s6=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc4&&low==soc3

s4=pwm2;s8=pwm1;s7=1;

s1=0;s2=0;s3=0;s5=0;s6=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc4&&low==soc5

s7=pwm1;s9=pwm1;s10=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s8=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc4&&low==soc6

s7=pwm1;s9=pwm1;s11=pwm2;s12=1;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s8=0;s10=0;s13=0;s14=0;

elseif high==soc4&&low==soc7

s7=pwm1;s9=1;s11=pwm1;s13=pwm2;s14=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s8=0;s10=0;s12=0;

%soc5 starts here

elseif high==soc5&&low==soc1

s10=pwm1;s9=pwm1;s2=pwm2;s4=pwm2;s6=1;

s1=0;s3=0;s5=0;s7=0;s8=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc5&&low==soc2

s10=pwm1;s7=pwm1;s4=pwm2;s3=pwm2;

s1=0;s2=0;s5=0;s6=0;s8=0;s9=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc5&&low==soc3

s10=pwm1;s9=pwm1;s6=pwm2;s5=pwm2;

s1=0;s2=0;s3=0;s4=0;s7=0;s8=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc5&&low==soc4

s10=pwm1;s8=pwm1;s7=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s9=0;s11=0;s12=0;s13=0;s14=0;

elseif high==soc5&&low==soc6

s9=pwm1;s11=pwm1;s12=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;s10=0;s13=0;s14=0;

elseif high==soc5&&low==soc7

s9=pwm1;s11=pwm1;s12=pwm2;s14=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s10=0;s8=0;s13=0;

%soc6 starts here

elseif high==soc6&&low==soc1

s12=pwm1;s10=1;s8=pwm1;s2=pwm2;s4=pwm2;

s1=0;s3=0;s5=0;s6=0;s7=0;s9=0;s11=0;s13=0;s14=0;

elseif high==soc6&&low==soc2

s12=pwm1;s10=pwm1;s6=pwm2;s3=pwm2;s4=1;

s1=0;s2=0;s5=0;s7=0;s8=0;s9=0;s11=0;s13=0;s14=0;

elseif high==soc6&&low==soc3

s12=pwm1;s9=pwm1;s6=pwm2;s5=pwm2;

s1=0;s2=0;s3=0;s4=0;s7=0;s8=0;s10=0;s11=0;s13=0;s14=0;

elseif high==soc6&&low==soc4

s12=pwm1;s10=pwm1;s8=pwm2;s7=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s9=0;s11=0;s13=0;s14=0;

elseif high==soc6&&low==soc5

s12=pwm1;s10=pwm1;s9=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;s11=0;s13=0;s14=0;

elseif high==soc6&&low==soc7

s11=pwm1;s13=pwm1;s14=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;s9=0;s10=0;s12=0;

%soc7 starts here

elseif high==soc7&&low==soc1

s14=pwm1;s13=pwm1;s9=pwm2;s7=1;s2=pwm2;s5=1;

s1=0;s3=0;s4=0;s6=0;s8=0;s10=0;s11=0;s12=0;

elseif high==soc7&&low==soc2

s14=pwm1;s11=pwm1;s9=pwm2;s3=pwm2;s5=1;

s1=0;s2=0;s4=0;s6=0;s7=0;s8=0;s10=0;s12=0;s13=0;

elseif high==soc7&&low==soc3

s14=pwm1;s12=pwm1;s5=pwm2;s9=pwm2;s7=1;

s1=0;s2=0;s3=0;s4=0;s6=0;s8=0;s10=0;s11=0;s13=0;

elseif high==soc7&&low==soc4

s14=pwm1;s11=pwm1;s9=pwm2;s7=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s8=0;s10=0;s12=0;s13=0;

elseif high==soc7&&low==soc5

s14=pwm1;s12=pwm1;s10=pwm2;s9=pwm2;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;s11=0;s13=0;

elseif high==soc7&&low==soc6

s14=pwm1;s11=pwm2;s13=pwm1;

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;s9=0;s10=0;s12=0;

else

s1=0;s2=0;s3=0;s4=0;s5=0;s6=0;s7=0;s8=0;s9=0;s10=0;s11=0;s12=0;s13=0;s14=0;

end

end

the code is running but it didnt balance

Answer 2

[KSSV]

You should not use while. Repalce it with if.

function [x,y] = fcn(u)
% u = battery voltage
% x=1 battery charge switch
% y=1 battery discharge switch

    if (u<=0.9) % battery charging
        if (u<=1.2)
            x=1;
            y=0;
        end
    elseif (u>1.2) || (u>0.9) && (u<1.2) %battery discharge
        if (u>=0.9)
            x=0;
            y=1;
        end
    else
        x=0;
        y=0;
    end
end

[Serdar GÜNAY]

it didn't work again.

Error:

Output argument 'x' is not assigned on some execution paths.

If the battery voltage is less than 0.9, it will charge until it reaches 1.2 volts and exit this cycle.

If the battery voltage is between 0.9 and 1.2, it will discharge to 0.9, exit this cycle and go back to the first condition

[KSSV]

Tell me for what input it din't work?

[Serdar GÜNAY]

Error: Output argument 'x' is not assigned on some execution paths.

[Ameer Hamza]

It feels like you are not showing the actual code you are running on your PC. The code in KSSV answer will assign values to output variables on all execution paths.

[KSSV]

You need to rethink on your code...

if (u<=0.9) % battery charging
        if (u<=1.2)
            x=1;
            y=0;
        end
elseif 

The above line looks ridiculous ...Now as you got to know using while is wrong and you have to use if elseif...you can proceed on your own.

[Serdar GÜNAY]

14/5000

that's all the code. Sorry.. I am trying to express my purpose to you. I am not oppose you. But code not working. I hope you can help me. thank you

• 

[KSSV]

Hey...it is not you are opposing me...I said it because..now you understood the gist..and you can do it...

[Serdar GÜNAY]

if (u <= 0.9)% battery charging

if (u <= 1.2)

x = 1;

y = 0;

end

elseif

this condition not working. 1. if is working, 2. if is not working. u initial value <=0.9 , when u is greater than 0.9, y = 1 x = 0.