Technical data

Creating STL Source Files
13.2 Rules for Programming in STL Source Files
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 285
13.2.6 Permitted Block Properties for Each Block Type
The following table shows which block properties can be declared for which block types:
Property OB FB FC DB UDT
KNOW_HOW_PROTECT • •
•
• −
AUTHOR • •
•
• −
FAMILY • •
•
• −
NAME • •
•
• −
VERSION • •
•
• −
UNLINKED − −
−
• −
NON_RETAIN
− − − • −
READ_ONLY − −
−
• −
Setting Block Protection with KNOW_HOW_PROTECT
You can protect your blocks from unauthorized users by setting block protection using the keyword
KNOW_HOW_PROTECT when you program the block in the STL source file.
This block protection has the following consequences:
• If you want to view a compiled block at a later stage in the incremental STL, FBD, or Ladder
editors, the code section of the block cannot be displayed.
• The variable declaration list for the block displays only the variables of the declaration types
var_in, var_out, and var_in_out. The variables of the declaration types var_stat and var_temp
remain hidden.
• The keyword KNOW_HOW_PROTECT is entered before any other block properties.
Setting Write Protection for Data Blocks with READ_ONLY
For data blocks, you can set up write protection so that the block is not overwritten during program
processing. The data block must exist in the form of an STL source file to do this.
Use the keyword READ_ONLY in the source file to set write protection. This keyword must appear
immediately before the variable declarations in a line on its own.