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86
Section 4
APP
E
NDIX
E3X-DRT21-S
User’s Manual
Section 4
Errors and Countermeasures
Errors and Countermeasures
The following table describes the LED statuses, probable causes and countermeasures.
LED status
Probable causes
Countermeasure
MS and NS
LED not lit.
Power is not supplied to the
Unit.
Supply the communications power to the Unit through the
DeviceNet communications connector.
Supply voltage is outside the
permissible range.
Use the supply voltage within the permissible range.
The Unit is damaged.
Replace the Unit.
MS LED lit red.
The Unit is damaged.
Replace the Unit.
MS LED lit
green.
NS LED
flashing green.
DeviceNet Communications
The Unit is waiting for
connection to DeviceNet
communications.
Check the following items and then restart the Unit.
• Are cable lengths (trunk/branch lines) appropriate?
• Are cables shorted, broken, or loose?
• Is the wiring correct?
• Is terminating resistance connected to both ends of the
trunk line only?
• Is there too much noise?
• Is the power turned ON to the master?
The Unit is damaged.
Replace the Unit.
MS LED lit
green.
NS LED lit red.
DeviceNet is in Busoff status.
Check the following items and then restart the Unit.
• Are cable lengths (trunk/branch lines) appropriate?
• Are cables shorted, broken, or loose?
• Is terminating resistance connected to both ends of the
trunk line only?
• Is there too much noise?
The same node address has
been assigned to two or more
nodes.
Set the node addresses correctly.
The Unit is damaged.
Replace the Unit.
MS LED lit
green.
NS LED
flashing red.
A communications timeout error
has occurred.
Check the following items and then restart the Unit.
• Are cable lengths (trunk/branch lines) appropriate?
• Are cables shorted, broken, or loose?
• Is terminating resistance connected to both ends of the
trunk line only?
• Is there too much noise?
The Unit is damaged.
Replace the Unit.
SS LED not lit.
No Sensors are connected.
Connect the Sensors correctly.
The Sensors adjacent to the
communication unit are
damaged.
Replace the Unit adjacent to the communication unit.
The power is turned ON
while the Mobile Console was
connected.
Temporarily disconnect the Mobile Console.
The Unit is damaged.
Replace the Unit.