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Configuration
4.4
Configuring a CP 243-1 from a user program
The configuration data of the CP 243-1 are stored in the S7-200 CPU memory and
can therefore be changed directly from an S7-200 user program. The cyclic redun-
dancy check (CRC) must be disabled for the configuration data so that the
CP 243-1 will accept configuration data which were changed in this way during the
next startup. For this purpose, the value 16#AC must be entered for Byte 13 of the
CDB data structure. This takes place automatically as soon as the CRC mecha-
nism is switched off in the Ethernet Wizard.
Attention
Configuring the CP 243-1 from a user program is only recommended for experi-
enced programmers.
The CP 243-1 cannot completely check the configuration data for consistency with
regard to intentional and unintentional changes after the CRC check has been
switched off. Therefore, in this case there is no guarantee whatsoever that the CP
or the components connected in the network will function correctly.
Note
Data of the "WORD" (2 bytes) or "DWORD" (4 bytes) type are stored in an S7-200
in "big endian" format, i.e.
Address n:
Address n+1:
36
MSB
LSB
(analogous for DWORD).
09/02
CP 243-1
J31069-D0428-U001-A1-7618
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