User manual

Publication LOGIX-AP010B-EN-P - May 2010 43
Software Conversions - Program Structure Chapter 2
Internal Memory
Addressing
Internal controller memory locations are available as flag words/bits or
DataBlock (DB) words/bits.
Flag Words/Bits
Step 5 internal controller flag address locations have these formats:
• F3.5 for a bit
• FB7 for a byte
• FW10 for a word
• FD for a double word
• S for an extended memory location
These addresses can then be assigned symbolic names via the symbols table.
RSLogix 5000 software does not use this type of address format. Instead,
memory locations are defined and referenced solely by the name assigned to
them in the tag database.
Example
In Step 5, an internal PLC location for storing tank weight could be defined as
follows.
This can be used in the PLC logic to perform a comparison as shown below.