Siemens SIMATIC FM 353 - Machine Data

Defining Parameters
5-9
FM 353 Stepper Drive Positioning Module
6ES7 353-1AH01-8BG0
Data block structure
Table 5-2 gives a rough picture of data block structure.
Table 5-2 Data block structure
Addresses/
Offset
Contents Comment
DB header System information, not relevant for
user
0 and above User data area / structure header Information for labeling of data
block within the system
24 and above
for MD, other-
wise 32
User data Parameterization data
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 Value Significance of the variables Comment
DB header
0 WORD Rack slot Module address
2 WORD DB No. ( 1000) As in DB header
4 DWORD Reserved
8 WORD Error No. (from FM) With MMI services
10 WORD 1 Channel number
12 2 STRING MD DB identifier/type 2 ASCII characters
16 DWORD 353 Module identifier FM 353
20 4 CHAR 0 Version number/block number (DB structure)
24 and
above.
..
See machine data list MD5 − MD51
Note: MD address in DB = (MD-Nr. −5) * 4 +24