Omron CJ1W-DRM21 3 I/O Link Problems, Use the following table to troubleshoot I/O Link problems

Troubleshooting	Section 9-3
Error	Probable cause
The DeviceNet Unit’s MS indicator is ON and	• If the DeviceNet Unit’s 7-segment display is displaying an error code,
green, but the NS indicator continues to flash	refer to the tables in 9-1 Troubleshooting with the DeviceNet Unit In-
green.	dicators.
(The NS indicator normally goes ON 2 s after	• Restart the Unit. Replace the Unit if it doesn’t restart.
the MS indicator.)
The DeviceNet Unit’s MS and NS indicators are	• Check that the DeviceNet Unit’s baud rate matches the baud rates set
ON and green, but the 7-segment display contin-	on all of the slaves. If they don’t match, set all of the baud rates to the
ues to flash the master’s node address.	same value.
(The node address normally stops flashing	• Make sure that there are121-Ωterminators connected at both ends
within 8 s after the NS lights.)	of the trunk line. Connect 121-Ωterminators if the wrong resistance
	is being used.
	• Check whether all of the slaves’ settings are correct.
	• Check whether the communications cables are wired correctly.
	• Check whether the power supply cables and power supply are wired
	and set correctly.
	• Check for broken wires in the communications and power supply ca-
	bles attached to the connectors.
	• Check whether the slaves are operating properly.
	When an OMRON slave is being used, refer to the DeviceNet Slaves
	Operation Manual (W347).
	• If another company’s slave is being used, refer to that slave’s user’s
	manual.

9-3-3 I/O Link Problems

Use the following table to troubleshoot I/O Link problems.

Error	Probable cause
The I/O isn’t simultaneous.	Observe the following precautions when writing application programs:
	• The simultaneity of node-units of data is ensured between the PC and
	DeviceNet Unit.
	• In OMRON slaves, the simultaneity of word-units of data is ensured.
	• If another company’s slave is being used, refer to that slave’s user’s
	manual for details.
At startup, OFF outputs are output from the	When the master is operating in scan list enabled mode and the PC is
slaves.	set to maintain the status of I/O area bits, those held output points will
	be output from the output slaves at startup.
	Be sure to perform the Create Scan List operation and operate the
	master with the scan list enabled.
	Refer to the CS1 Series CPU Unit Operation Manual (W339) or the CJ
	Series CPU Unit Operation Manual (W393) for details on maintaining I/
	O area data with the IOM Hold Bit.

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