Technical data

Checking Block Consistency and Time Stamps as a Block Property
15.6 Time Stamps in UDTs and Data Blocks Derived from UDTs
Programming with STEP 7
330 Manual, 05/2010, A5E02789666-01
15.6 Time Stamps in UDTs and Data Blocks Derived from UDTs
User-defined data types (UDTs) can, for example, be used to create a number of data blocks with
the same structure.
Code Time stamp
The code time stamp is updated on every change.
Interface Time stamp
The interface time stamp is updated when the interface description is changed (changes to data
types or initial values, new parameters).
The interface time stamp of a UDT is also updated when the ASCII source file is compiled.
Rules for Opening Without Conflicts
• The interface time stamp of the user-defined data type must be older than the interface time
stamp in logic blocks in which this data type is used.
• The interface time stamp of the user-defined data type must be identical to the time stamp of a
data block derived from a UDT.
• The interface time stamp of the user-defined data type must be younger than the time stamp of
a secondary UDT.
Procedure if a Time stamp Conflict Occurs
If you change a UDT definition that is used in a data block, function, function block, or another UDT
definition, STEP 7 reports a time stamp conflict when the block is opened.
The UDT component is shown as a fanned-out structure. All variable names are overwritten by
values preset by the system.
15.7 Correcting the Interfaces in a Function, Function Block, or UDT
If you need to correct the interface in an FB, FC, or UDT, proceed as follows to avoid time stamp
conflicts:
1. Generate an STL source file from the block you want to change and all directly or indirectly
referenced blocks.
2. Save the changes in the source file you generated.
3. Compile the modified source file back into blocks.
You can now save/download the interface changes.