If Then

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If Then

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if condition then





The simplest if statement evaluates a condition and performs the specified equation(s) if the condition is true. If the condition is not true, 20-sim ignores the equation(s).


b = false;

y = ramp(1);

u = -ramp(1);

if time > 5 then

 y = -ramp(1); // equations to be executed if condition is true,

 u = ramp(1); // these are not executed if condition is false


if time == 10 then // note the use of the equal operator ==

 b = true; // equations to be executed if condition is true,



1.The output of the condition must be a boolean.


1.Take care when using an event functions in if-then-else statements. In if-then-else statements only the equations of the true parts are evaluated, so event functions may not always be triggered!
2.There is also an if-then-else statement.
3.Equations within an if statement have to be written in the correct order of execution, i.e. they are not rewritten into a causal form but executed sequentially.