12   Troubleshooting
12 - 54
NX-series EtherNet/IP Coupler Unit User’s Manual (W536)
12-5 Troubleshooting Other Errors
This section describes error symptoms that cannot be resolved with the methods for checking for errors 
and troubleshooting that were described earlier.
Status Possible cause and correction
When the Unit configuration was 
registered, the TS indicator on the 
EtherNet/IP Coupler Unit flashed 
green, and the TS indicators on the 
first few NX Units near the Ether-
Net/IP Coupler Unit flash green and 
the TS indicators on the other NX 
Units are not lit.
The NX bus connector on the left side of the Units where the TS indica-
tors are not lit is not connected properly.
Connect it properly and cycle the power supply.
• All TS indicators on the Ether-
Net/IP Slave Terminal (EtherNet/IP 
Coupler Unit and NX Units) are lit 
green.
• When the output of the Ether-
Net/IP Coupler is active, the OUT 
indicator on the Digital I/O Unit is lit 
yellow but the actual output is 
OFF.
• A device (e.g., sensor) that is con-
nected to the Digital I/O Unit is 
ON, but a signal is not input, and 
the IN and OUT indicators are both 
not lit.
• The power supply to the Additional NX Unit Power Supply Unit is not 
turned ON. Check the wiring and turn ON the power supply.
• The NX bus connectors between the Units are not connected properly. 
Make sure that the Unit hookup guides are properly engaged.
• The wiring for the I/O power supply is disconnected. Check the wiring.
Not lit.
EtherNet/IP 
Coupler Unit
NX Units
Faulty connection
TS indicator status
Flashing.