Omron CJ Series Operation Manual page 200

5 Operation
Determine which slave device failed during network startup or data exchange. To do this, use the
CJ1W-PRM21 Master DTM Monitoring User Interface or the slave DTM (see 5-7-1 Monitoring the
Master Unit and the Network and 5-7-2 Monitoring Slave Status) to determine the slave and its type
of failure.
Remove the cause of the failure.
Press the OPERATE Button in the Master Units Monitoring window.
Alternatively, the Master can also be switched to OPERATE from the CPU program.
5-48 CJ-series PROFIBUS Master Unit Operation Manual for NJ-series CPU Unit (W509)