8   Troubleshooting
8 - 14
NX-series Analog I/O Units User’s Manual for Analog Input Units and Analog Output Units (W522)
This section describes the information that occurs on the Analog Input Units and Analog Output Units.
*6. Refer to the appendices of the troubleshooting manual for the connected CPU Unit or Industrial PC for the applicable 
range of the HMI Troubleshooter.
Error Descriptions
Event name Non-volatile Memory Hardware Error Event code 0020 0000 hex
Meaning An error occurred in non-volatile memory.
Source Depends on where the Support 
Software is connected and the 
system configuration.
Source details NX Unit Detection 
timing
When power is 
turned ON to 
the NX Unit
Error 
attributes
Level Minor fault Log category System
Recovery For the NX bus of CPU Units
Cycle the power supply to the Unit or restart the NX bus.
For Communications Coupler Units
Cycle the power supply to the Unit or restart the Slave Terminal.
If the errors are detected in the Controller, reset all of the errors in the Controller.
Effects
User program
Continues. Operation I/O refreshing for the NX Unit stops. Messages can-
not be sent to the NX Unit.
Sys-
tem-defined 
variables
Variable Data type Name
None --- ---
Cause and 
correction
Assumed cause Correction Prevention
Non-volatile memory failure. For the NX bus of CPU Units
Cycle the power supply to the Unit 
or restart the NX bus. If the error 
persists even after you make the 
above correction, replace the rele-
vant NX Unit.
For Communications Coupler 
Units
Cycle the power supply to the Unit 
or restart the Slave Terminal. If the 
error persists even after you make 
the above correction, replace the 
relevant NX Unit.
None
Attached 
information
None
Precautions/
Remarks
None