Machine Data - Siemens SIMATIC FM 353 Manual

Data block structure
Table 5-2 gives a rough picture of data block structure.
Table 5-2
Addresses/
Offset
0 and above
24 and above
for MD, other-
wise 32
Detailed data block structures and parameterization data for the individual types of
data blocks can be found in the following sections.
5.3.1

Machine data

DB structure
Table 5-3 gives you an overview of the structure of the "machine data" data block
(DB-MD).
Table 5-3 DB structure − machine data
Byte Variable type
0 WORD
2 WORD
4 DWORD
8 WORD
10 WORD
12 2 STRING
16 DWORD
20 4 CHAR
24 and
above.
..
Note: MD address in DB = (MD-Nr. −5) * 4 +24
FM 353 Stepper Drive Positioning Module
6ES7 353-1AH01-8BG0
Data block structure
Contents
DB header
User data area / structure header
User data
Value Significance of the variables
DB header
Rack slot
DB No. (w 1000)
Reserved
Error No. (from FM)
1 Channel number
MD DB identifier/type
353 Module identifier
0 Version number/block number
See machine data list MD5 − MD51
Defining Parameters
Comment
System information, not relevant for
user
Information for labeling of data
block within the system
Parameterization data
Comment
Module address
As in DB header
With MMI services
2 ASCII characters
FM 353
(DB structure)
5-9