Siemens SIMATIC S7-1200 - Page 380

Extended instructions
9.2 String and character
S7-1200 Programmable controller
380 System Manual, V4.2, 09/2016, A5E02486680-AK
Example: Calling GetInstancePath to get the path of a multi-instance FB call
In the following example, the FB_Level_3 function block calls the GetInstancePath
instruction.
● The FB_Level_3 function block stores its data in the calling FB_Level_2 function block.
● The FB_Level_2 function block in turn stores its data in the calling FB_Level_1 function
block.
● The FB_Level_1 function block in turn stores its data in its instance data block
IDB_LEVEL_1. Through the use of multi-instances, the instance data block of FB_Level_1
contains all data of the three function blocks.
The GetInstancePath instruction returns the following values for this example, depending on
the value of the SIZE parameter:
SIZE
GetInstancePath returns
Explanation
1 '...'
• First character of WSTRING:'
• Identifier that the name was truncated: ...
• Last character of WSTRING:'
2 '"...'
• First character of WSTRING:'
• The first character of the name and identifier that the
name was truncated:"...
• Last character of WSTRING:'
3 '"I...'
• First character of WSTRING:'
• The first two characters of the name and identifier that
the name was truncated:"... "I...
• Last character of WSTRING:'