Siemens SINUMERIK 808D Parameter Manual page 472

PLC user interface
6.1 Addressing ranges
Note
The permitted offset for an address depends on the access:
● Bit or byte access: any offset.
Byte-size variables are placed one beside another seamlessly in a DB.
● Word access: the offset must be divisible by 2.
Word-size variables (2 bytes) are always saved on straight offsets.
● Double word access: the offset must be divisible by 4.
Double word-size variables (4 bytes) are always saved on offsets that are divisible by 4.
Special bit memory SM bit definition (read-only)
Special marker bit definition
SM 0.0
SM 0.1
SM 0.2
SM 0.3
SM 0.4
SM 0.5
SM 0.6
Variable access rights
[r]
[r/w]
Data format information
1
8
16
32
Note
All of the empty fields in the user interface are "reserved for Siemens" and may neither be
written to nor evaluated.
Fields designated with "0" always have the value "logical 0".
If there is no data format information, you can read or write to all the specified data formats.
472
SM bits
Bit memory with the defined ONE signal
Initial setting: first PLC cycle '1', subsequent cycles '0'
buffered data lost - only valid in first PLC cycle
('0' data ok, '1' data lost)
POWER ON: first PLC cycle '1', subsequent cycles '0'
60 s clock (alternating '0' for 30 s, then '1' for 30 s)
1 s clock (alternating '0' for 0.5 s, then '1' for 0.5 s)
PLC cycle clock (alternating one cycle '0', then one cycle'1')
You can "read only" designated area
You can "read and write" designated area
BIT
BYTE
INT/WORD
DINT/DWORD/REAL
Description
Parameter Manual
List Manual, 01/2017