Siemens SIMATIC FM 351 Manual page 43

Job Status
You can check the status of job execution using the return value RET_VAL and the
JOBBUSY activity bit in the channel DB. You can evaluate the status of a single
job based on the trigger, done, and error bits of the job.
Job active
Job completed
without error
Job completed
with error
Write job
aborted
Response to Errors
If incorrect data were written during a write job, the channel returns the message
DATA_ERR = 1 in the channel DB. 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 also reset but only the error bit
(_ERR) is set for all write jobs still pending. Any pending write jobs are
canceled, since one job may depend on another.
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 errors, refer to the description of the parameters
JOB_ERR and DATA_ERR (see Section 11 and Appendix C.3, page C-11).
FM 351 Positioning Module
C79000-G7076-C351-02
RET_VAL JOBBUSY
1 1
0 0
–1 0
–1 0
Programming the FM 351
Trigger bit Done bit
_EN _D
1 0
0 1
0 1
0 0
Error bit
_ERR
0
0
1
1
6-9