Technical data

Creating Blocks and Libraries
9.3 Creating Blocks
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 225
9.3 Creating Blocks
9.3.1 Blocks Folder
You can create the program for an S7 CPU in the form of:
• Blocks
• Source files
The folder "Blocks" is available under the S7 program for storing blocks.
This block folder contains the blocks you need to download to the S7 CPU for your automation
task. These loadable blocks include logic blocks (OBs, FBs, FCs) and data blocks (DB). An empty
organization block OB1 is automatically created with the block folder because you will always need
this block to execute your program in the S7 CPU.
The block folder also contains the following objects:
• The user-defined data types (UDT) you created. These make programming easier but are not
downloaded to the CPU.
• The variable tables (VAT) that you can create to monitor and modify variables for debugging
your program. Variable tables are not downloaded to the CPU.
• The object "System Data" (system data blocks) that contains the system information (system
configuration, system parameters). These system data blocks are created and supplied with
data when you configure the hardware.
• The system functions (SFC) and system function blocks (SFB) that you need to call in your
user program. You cannot edit the SFCs and SFBs yourself.
With the exception of the system data blocks (which can only be created and edited via the
configuration of the programmable logic controller), the blocks in the user program are all edited
using the respective editor. This editor is started automatically by double-clicking the respective
block.
Note
The blocks you programmed as source files and then compiled are also stored in the block folder.