Siemens SIMATIC S7-1200 - Page 374

Extended instructions
9.2 String and character
S7-1200 Programmable controller
374 System Manual, V4.2, 09/2016, A5E02486680-AK
Usage
Note the following tips on using the GetSymbolPath instruction:
● Specify the block interface through which the name of the input tag is read at the
VARIABLE parameter of the instruction:
– If a data block tag supplies the input parameter, GetSymbolPath outputs the name of
the DB, contained structures and the name of the tag.
– If a PLC tag supplies the input parameters GetSymbolPath outputs the name of the
PLC tag.
– If a constant supplies the input parameter, GetSymbolPath outputs the constant value.
● To limit the length of the read tag name, use the SIZE parameter. If the name has been
truncated, this is indicated by the character "..." (Unicode character 16#2026) at the end
of the name. Note that this character has the length 1.
Example: Meaning of the SIZE parameter
The following example illustrates the meaning of the SIZE parameter. GetSymbolPath has
read out the following tag name is read out from the block interface: "MyPLCTag" (The
double quotes at the start and end belong to the name.)
SIZE
GetSymbolPath 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 '"M...'
• First character of WSTRING:'
• The first two characters of the name and identifier that
the name was truncated:"... "M...
• Last character of WSTRING:'
6 '"MyPL...'
• First character of WSTRING:'
• The first five characters of the name and identifier that
the name was truncated: "MyPL...
• Last character of WSTRING:'
0 '"MyPLCTag"'
• First character of WSTRING:'
• All characters of the name: "MyPLCTag"
• Last character of WSTRING:'