Lenze DDS v2.3 Manual do Utilizador descarregar pdf (Página 46)

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4-8

DDS EN 2.3

4.3.9 FOR loop

Use the FOR loop to program repetitive procedures.

Syntax:

INT_Var :INT;

FOR <INT_Var>:=<INIT_VALUE> TO <END_VALUE> {BY <step size>} DO

END_FOR;

• The part in curly brackets {} is optional.

• The <instructions> are executed as long as the counter<INT_Var> is not greater than

the<END_VALUE>.

• A check is performed before the <instructions> are executed so that the

<instructions> will never be executed if <INIT_VALUE> is greater than <END_VALUE>.

• Whenever the section <instructions> has been executed, <INT_Var> will be increased

by <step size>.

• The step size can have any integer value. If no other step size is specified, step size 1 will be

used. The loop must terminate because <INT_Var> will only become greater.

• If <INIT_VALUE> is greater than <END_VALUE> and <step size> is negative, the FOR

loop is counted in opposite direction.

• If <INIT_VALUE> is less than <END_VALUE> and <step size> is negative, the FOR loop

will not be executed.

Example:

FOR Counter:=1 TO 5BY1DO

Var1:=Var1*2;

END_FOR;

Res:=Var1;

Assuming that the variable Var1 has been pre-assigned value 1, it will be 32 after the FOR loop.

Caution!

<END_VALUE> must not be the limit value of the counter <INT_VAR>.

If, for instance, the variable Counter is of type SINT, <END_VALUE> must not be 127 since

otherwise the loop would be endless.

After completion of the FOR loop, Counter has a value 6.

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Lenze DDS v2.3 Manual do Utilizador Página 46