12   Troubleshooting and Maintenance
12 - 16
GX-series EtherCAT Slave Unit User’s Manual
 Error Descriptions
Event name Expansion Unit Hardware Error Event code 04A00000 hex
Meaning An Expansion Unit was disconnected during operation or a signal between the Slave Unit and Expansion Unit was 
broken.
Source EtherCAT Master Function Module Source details Slave Detection 
timing
Continuously
Error attributes Level Minor fault Recovery Error reset (after 
cycling Slave Unit 
power)
Log category System
Effects User program Continues Operation The Slave Unit where the error occurred performs the 
error output operation (fail-safe).
LED EtherCAT NET RUN EtherCAT NET ERR EtherCAT LINK/ACT
--- --- ---
System-defined 
variables
Variable Data type Name
None --- ---
Cause and 
correction
Assumed cause Correction Prevention
The Expansion Unit was 
disconnected during operation.
Turn OFF the power supply, mount 
the Expansion Unit, and turn the 
power supply back ON.
Do not allow the Expansion Unit to be 
disconnected during operation.
A signal between the Slave Unit and 
Expansion Unit was broken.
Turn OFF the power supply, mount 
the Expansion Unit, and turn the 
power supply back ON.
If cycling the power supply does not 
correct the problem, replace the 
Expansion Unit.
None
Attached 
information
None
Precautions/
Remarks
The emergency error code is 5020 hex.
Event name Slave Hardware Error Event code 04A20000 hex
Meaning A hardware error occurred in the EtherCAT communications section.
Source EtherCAT Master Function Module Source details Slave Detection 
timing
Continuously
Error attributes Level Minor fault Recovery Error reset (after 
cycling Slave Unit 
power)
Log category System
Effects User program Continues Operation The Slave Unit where the error occurred performs the 
error output operation (fail-safe).
LED EtherCAT NET RUN EtherCAT NET ERR EtherCAT LINK/ACT
--- --- ---
System-defined 
variables
Variable Data type Name
None --- ---
Cause and 
correction
Assumed cause Correction Prevention
The Slave Unit is faulty. If cycling the power supply does not 
correct the problem, replace the 
Slave Unit.
None
Attached 
information
None
Precautions/
Remarks
The emergency error codes are 7030 hex and 7100 hex.