Slice Access - Siemens S7-1200 Programming Manualline

3 General Programming
3.6 Symbolic addressing
Advantages
High programming efficiency
Easy multiple usability thanks to PLC data types
Recommendation
Use PLC data types for access to I/O areas, for example, to symbolically
receive and send drive telegrams.
3.6.5

Slice access

For S7-1200/1500 controllers, you can access the memory area of tags of the Byte,
Word, DWord or LWord data type. The division of a memory area (e.g. byte or
word) into a smaller memory area (e.g. Bool) is also called slice. In the figure below
displays the symbolic bit, byte and word accesses to the operands.
Figure 3-30: Slice access
Advantages
High programming efficiency
No additional definition in the tag declaration required
Simple access (e.g. control bits)
Recommendation
Use the slice access rather than AT construct via accessing certain data areas
in operands.
Note You will find further information in the following entry:
How in STEP 7 (TIA Portal) can you access the unstructured data types bit-by-
bit, byte-by-byte or word-by-word and symbolically?
http://support.automation.siemens.com/WW/view/en/57374718
Programming Guideline for S7-1200/1500
V1.2, Entry ID: 81318674
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