Omron CS1W-DRM21, CJ1W-DRM21 Troubleshooting, CPU Unit’s ERR/ALM Indicator Lit or Flashing

TroubleshootingSection 9-3

9-3	Troubleshooting
9-3-1	CPU Unit’s ERR/ALM Indicator Lit or Flashing
	Use the following table to troubleshoot the network when the DeviceNet Unit
	is mounted and the CPU Unit’s ERR/ALM indicator is lit or flashing.
	Error			Probable cause
An I/O verification error occurred.		•	Make sure that the Unit is connected properly.
		• Check the I/O table with the I/O Table Verification operation and correct it
			if necessary. After correcting it, perform the I/O Table Create operation.
A CPU Bus Unit setting error occurred.		•	The CPU Bus Unit model registered in the I/O table does not match the
			model of CPU Bus Unit actually mounted. Check the I/O table with the I/O
			Table Verification operation and correct it if necessary.
		• After correcting the I/O table, perform the I/O Table Create operation.
A CPU Bus error occurred.		•	Make sure that the Unit is connected properly.
		• Restart the Unit. Replace the Unit if it doesn’t restart.
An I/O Bus error occurred.		•	Make sure that the Unit is connected properly.
		• Restart the Unit. Replace the Unit if it doesn’t restart.
	Note Refer to the CS1 Series CPU Unit Operation Manual (W339) or the CJ Series
	CPU Unit Operation Manual (W393) for more details on these errors.
9-3-2	Remote I/O Communications Disabled
	Use the following table to troubleshoot the network when remote I/O data
	communications won’t start. (The I/O Data Communications Flag remains
	OFF in Master Status 1.)
	Error			Probable cause
All of the DeviceNet Unit’s indicators are OFF.				• Check whether power is being supplied to the PC.
				• Check whether the DeviceNet Unit is mounted in the Backplane cor-
				rectly.
				• When a watchdog timer (WDT) error has occurred in the PC, follow
				the procedures described in the PC’s manual to correct the problem.
				• All of a CS1W-DRM21 or CJ1W-DRM21 Unit’s indicators will be OFF
				when a CPU Bus Unit error has occurred. Check for a CPU Bus Unit
				error.
				• Restart the Unit. Replace the Unit if it doesn’t restart.
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 remains OFF.				refer to the tables in 9-1 Troubleshooting with the DeviceNet Unit In-
(The NS indicator normally goes ON about 2 s				dicators.
after the MS indicator.)				• Make sure that the master’s unit number setting is correct.
				• Make sure that the unit number is not duplicated on another Special
				Unit.
				• Check the I/O table with the I/O Table Verification operation and cor-
				rect it if necessary. After correcting it, perform the I/O Table Create
				operation.
				Restart the Unit. Replace the Unit if it doesn’t restart.

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