Before you use the Loop adapter, it is important to understand
the following information:
-
You cannot select parameter types other than the selected
parameter type for expression formation or value substitution. For example,
if you have a For Each loop with a real parameter,
you cannot select a string parameter as one of its values; you can select
only another real parameter. The only exception is that you can select
integer parameters when the loop variable is real.
-
Proper loop execution requires that the parameters
(iteration parameter in For and For
Each loops, and condition parameters in While
and Do Until loops) are mapped correctly between
the parent loop and its subflows.
-
For While and Do Until loops to function properly,
all parameters that are used in the conditions and that are expected to change
their values during iterations must be input/output parameters. In this case
their values are preserved from one iteration to another by the Loop adapter.
For example, when creating a While loop with the
condition (N < 10) and a calculator in the subflow with the
expression N = N + 1, you must ensure that parameter
N is an input/output parameter in both the Loop adapter and the
Calculator adapter and that the parameter is mapped in both directions. If this
is not done, parameter N's values are always reset to the initial
value at every calculator execution, and the loop ends up running infinitely or
until it reaches the maximum number of iterations.
-
For all loops, the values of all output or input/output parameters after the
loop finishes are taken from the last iteration (highest run number,
not the last iteration to finish).