Simulink - How to create a conditional "if" block with more than 3 conditions?

Simulink - How do I create a conditional "if" block with more than 3 statements?

For example:

if(a>2)

do something

elseif (b>3)

do something else

elseif (c>4)

do something else

elseif (a<2 and c<2)

do something else

else

do default

end

What have I tried so far:

• The default "if" block permits only 2 conditions + default.
• I tried using the "case" but case only take one input and I need multiple inputs and 1 output (different depending on the conditions).

[Nom]

Try using

elseif (a<2) && (c<2)

for your third if statement

[Katarina Vuckovic]

The "and" is not an issue. I used sudo code in the example above. The issue is that simulink is not allowing more than 2 conditional statements in an if/else if structure.

[Nom]

I'm running the script and it seems to be running fine for me.

a = 1;
b = 1;
c = 1;

if(a>2)
    disp('first');
elseif (b>3)
    disp('second');
elseif (c>4)
    disp('third');
elseif (a<2 && c<2)
    disp('fourth');
else 
    disp('default');
end 

The issue I think you're facing is once a statement is true (e.g. if b is greater than 3, hence second if statement is correct). The program will exit the if statement and not check if a<2 && c<2.

One way to solve this issue (may not be the best but it should work) is just dividing the if statements into seperate statements instead of creating multiple elseifs.

[Katarina Vuckovic]

I used the user defined function and it worked. Thank you David K.

Also, the image is very helpful and now I see how I can do it in the window.

Answer 1

[David K.]

**Moved from questions to answer**

When you know the matlab code needed to do something in Simulink a Matlab Fuction Block can be added to solve the problem.

However, the IF block can also do multiple else ifs as shon below.

[Nachiket Bapat]

can someone let me know what im doing wrong ?