Siemens SIMATIC STEP 7 V5.2 Getting Started page 56

Creating a Program with Function Blocks and Data Blocks
When you create program structures with organization blocks, function blocks, and data
blocks, you must program the call for subordinate blocks (such as FB1) in the block above
them in the hierarchy (for example, OB1). The procedure is always the same.
You can also give the various blocks symbolic names in the symbol table (for example, FB1
has the name "Engine" and DB1 the name "Petrol").
You can archive or print out the programmed blocks at any time. The corresponding
functions can be found in the SIMATIC Manager under the menu commands File >
Archive or File > Print.
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Click the name Switch_On_PE. This
is taken from the pull-down list and
added automatically in quotation
marks.
Assign all the required addresses to
the variables of the function block
using the pull-down list.
Program the call for the function block
"Engine" (FB1) with the data block
"Diesel" (DB2) in a new network.
Proceed in the same way as for the
other call.
Save your program and close the
block.
You can find more information under Help > Contents
in the topics "Calling Reference Helps" under
"Language Description: STL," and "Program Control
Instructions."
A signal "PE_xxx" is assigned
to each of the variables for
the petrol engine.
STEP 7 Getting Started
A5E00171228-01