Siemens SINUMERIK 808D ADVANCED Series Commissioning Manual page 130

Structure of the DB-range address
Access Example
Bit DB3801.DBX1000.7
Byte DB3801.DBB0
Word DB4500.DBW2
Double Word DB2500.DBD3004
Note
The permitted offset for an address depends on the access as follows:
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.
Notes on the PLC interface signal address representation
Currently, PLC interface signal addresses are represented by the V structure on the HMI while the manual shows them by
the DB structure.
See the following table for the relationship between the two representations.
V Structure
Access
Bit
Byte
Word
Double Word
130
Description
Bit 7 of the byte with offset 0 in subrange 1 for axis 2, user range 38
Byte with offset 0 in subrange 0 for axis, user range 38
Work with offset 2 in subrange 0, range 0, user range 45
Double word with offset 4 in subrange 3, range 0, user range 25
Example
V38000002.1
VB38000002
VW38000002
VD38000004
DB Structure
Example
DB3800.DBX2.1
DB3800.DBB2
DB3800.DBW2
DB3800.DBD4
Access
Bit
Byte
Word
Double word
Commissioning Manual
6FC5397-4EP10-0BA8, 07/2018