PLC concepts
4.2 Accessing data
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
65
Figure 4-4 Accessing the accumulators
The SM bits provide a means for communicating information between the CPU and your
user program. You can use these bits to select and control some of the special functions of
the CPU, such as: a bit that turns on for the first scan cycle, a bit that toggles at a fixed rate,
or a bit that shows the status of math or operational instructions. You can access the SM bits
as bits, bytes, words, or double words:
Table 4- 12 Absolute addressing of SM memory
SM
[byte address].[bit address]
Byte, Word, or Double Word: SM
[size][starting byte address]
SMB86,
SMW300,
For more information, see the descriptions of the SM bits (Page 665).