Siemens SIMATIC NET CP 243-1 IT Technical Manual page 68

Configuration
Access to the configuration data in the memory of the CPU
The configuration data stored in the memory of the S7-200 CPU can also be
changed directly from an S7-200 user program. Before the CP 243-1 IT can accept
configuration data which have been changed like this when it boots again, the CRC
protective routine for configuration data must be disabled. The value 16#AC must
be entered in byte 13 of the CDB data structure. This takes place automatically as
soon as the CRC routine is disabled in the Internet wizard.
Caution
Configuration of the CP 243-1 IT from a user program is only recommended for
experienced programmers.
Since, after the CRC check is disabled, the CP 243-1 IT is no longer able to com-
pletely check the configuration data on the S7-200 CPU for consistency in relation
to desired and undesired changes, there is no guarantee whatsoever for this appli-
cation that the CP or the components connected on the network will function cor-
rectly.
Note
Data of type "WORD" (2 bytes) or "DWORD" (4 bytes) are stored on an S7-200 in
"big endian" format.
Address n:
Address n+1:
Alternate configuration of the IT functions
STEP 7 Micro/WIN 32 creates the configuration files for the IT functions. In princi-
ple, these files could also be created or manipulated by a conventional text editor
without STEP 7 Micro/WIN 32. For the structures of the configuration files, see
chapters 4.4.6, 4.4.7 and 4.4.8.
Caution
Only STEP 7 Micro/WIN 32 should be used to create and change the IT configura-
tion files. If other tools (e.g., text editors) are used to create or change these files,
configuration errors may not be detected. If you do this anyway, there is no guaran-
tee whatsoever that the CP 243-1 IT or the components connected in the network
will function correctly.
68
MSB
LSB (for DWORD accordingly)
03/03
CP 243-1 IT
J31069-D0429-U001-A0-7618