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Entry type: FAQ Entry ID: 14761527, Entry date: 12/21/2010
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How can you install block protection for an S7-SCL block?

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Instructions 
You can set a block protection for blocks by adding the attribute KNOW_HOW_PROTECT when programming the block. 

Activating block protection has the following effects. 

  • If you later open a compiled block with the incremental STL editor, the statement part of the block cannot be viewed.
  • The negotiation part of the block will only show the variables of declaration types VAR_IN, VAR_OUT and VAR_IN_OUT. The variables of the negotiation blocks VAR and VAR_TEMP remain hidden. 

When entering the block protection, the following applies.

  • The keyword is KNOW_HOW_PROTECT. It is entered before all other block attributes. 
  • OBs, FBs, FCs and DBs can be protected this way. 

Proceed as described in the table below to install block protection for an S7-SCL block.
 

No. Procedure
1 In the source folder of your STEP 7 program you open the S7-SCL source.
2 Insert a line with the attribute "KNOW_HOW_PROTECT" in the declaration part of the S7-SCL source.


Fig. 01

3 Save and compile the S7-SCL source.
4 Remove the S7-SCL source from the source folder. This activates block protection for your S7-SCL program.
5 Save your S7-SCL source.

A padlock is displayed on the block icon in the SIMATIC Manager to indicated that the function is protected.


Fig. 2: Icon for a protected function

Note
After the deletion of the S7-SCL source, the block cannot be changed anymore. Likewise, you can no longer deactivate the Know How protection.
More information on the topic of block protection ("Know_How_Protect") for DBs, FBs and FCs is available in Entry ID 10025431.

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