Siemens SIMATIC FM 452 Manual page 47

Response to Errors
If bad data were written by a write job, the module returns the message
DATA_ERR = 1. If an error occurs in communication with the module during a write
or read job, the cause of the error is entered in the JOB_ERR parameter in the
channel DB.
Error in a write job:
If an error occurs in a job, the trigger bit is reset and the error bit (_ERR) and
the done bit (_D) are set. The trigger bit is reset and the error bit (_ERR) is set
for all write jobs still pending.
The pending read jobs continue to be processed. JOB_ERR is set again for
each job.
Error in a read job:
If an error occurs in a job, the trigger bit is reset and the error bit (_ERR) and
the done bit (_D) are set.
The read jobs still pending continue to be processed. JOB_ERR is set again for
each job.
For more detailed information on the errors, refer to the parameters JOB_ERR and
DATA_ERR (see Chapter 11, Diagnostics and Appendix C.3, Page C-12)
FM 452 Electronic Cam Controller
C79000-G7076-C452-04
Programming the FM 452
6-9