Siemens CP 243-2 - Manual (Page 41)

Interface to the User Program in the S7-200 CPU
2-15
SIMATIC NET CP 243-2 AS-i Master
C79000-G8976-C142/02
Example of Access to the Error Register
Assuming that the CP 243-2 is inserted directly beside the S7-200 CPU.
Evaluate the special memory bits SM 11.0 to SM 11.2 in the SM area (for more
information about the special bit memory area of the S7-200 CPU, refer to /4/).
If an error has occurred, bit SM 11.0 and/or bit SM 11.2 is set.