Siemens SIMATIC S7 F Manual page 95

Programming
Recommendation: meaningful names for placed blocks
Give each block placed a meaningful name. You can choose any name.
Assigning a Value to a Fail-Safe I/O
To assign a value to a fail-safe I/O of an F-Block, proceed as follows:
1. Open the sheet view of the F-Block.
2. Select the I/O and open Object Properties by double-clicking it, for example.
Result: The "Select Structure Element" dialog box appears.
3. Double-click the first structure element in the "Select Structure Element" dialog
box.
Result: The "Properties – Inputs/Outputs" dialog box appears.
4. Enter the desired value in the "Value" text box and confirm with "OK".
Fail-Safe Systems
A5E00085588-03
5-13