Technical data

Basics of Designing a Program Structure
4.2 Blocks in the User Program
Programming with STEP 7
92 Manual, 05/2010, A5E02789666-01
Assigning Initial Values to Formal Parameters
You can assign initial values to the formal parameters in the declaration section of the FB. These
values are written into the instance DB associated with the FB.
If you do not assign actual parameters to the formal parameters in the call statement, STEP 7 uses
the values saved in the instance DB. These values can also be the initial values that were entered
in the variable declaration table of an FB.
The following table shows which variables can be assigned an initial value. Since the temporary
data are lost after the block has been executed, you cannot assign any values to them.
Data Type
Variable Elementary Data Type Complex Data Type Parameter Type
Input Initial value permitted Initial value permitted −
Output Initial value permitted Initial value permitted −
In/out Initial value permitted − −
Static Initial value permitted Initial value permitted −
Temporary − − −