Omron NJ501-1 Series User Manual page 206

5 Troubleshooting
Event name Impossible to Access Special Unit
Meaning An error occurred in data exchange between the CPU Unit and a Special Unit.
Source PLC Function Module
Error attributes Level
Effects User program
System-defined Variable
variables
None
Cause and Assumed cause
correction
The setting of the rotary switches or a
DIP switch pin on a Special Unit is not
correct.
• The node address is not correct.
• The communications mode is not
correct.
• The baud rate is not correct.
An error occurred in the Special Unit.
The Unit connection is faulty.
Noise
• There is data corruption in bus sig-
nals.
A Unit has failed.
Attached Attached information 1: Special I/O Unit: Error unit number + 20 hex
information
Attached information 2: Controller information
Precautions/ None
Remarks
5-40
Source details
Minor fault Recovery
Continues. Operation
Data type
---
Correction
Correct the setting of the rotary
switches or DIP switch pin on the
Special Unit. You can check the set-
ting error on the seven-segment dis-
play on the Special Unit.
Refer to the relevant manual to trou-
bleshoot the error.
Connect the Unit so that the connec-
tors mate correctly and slide the yel-
low sliders on the top and on the
bottom toward the back to lock them
into place.
If the error did not result from the
above causes, cycle the power to the
Controller and see if that clears the
error. If the error occurs frequently,
check the FG, power supply lines, and
other noise entry paths, and imple-
ment noise countermeasures as
required.
If the error did not result from the
above causes, and cycling the power
to the Controller or resetting the Con-
troller does not clear the error,
replace the Special Unit.
CPU But Unit: Error unit number + 10 hex
Event code 6401 0000 hex
CJ-series Unit Detection
timing
Reset error, cycle Log category
power supply, or
reset Controller.
The Special Unit stops.
Name
---
Prevention
Set the rotary switches and DIP
switch pins on the Special Units cor-
rectly.
Refer to the Unit manual and use the
Unit correctly.
Make sure that the Units are con-
nected correctly. Check for vibration
and shock.
Implement noise countermeasures.
Perform regular inspections.
NJ-series CPU Unit Hardware User's Manual (W500)
Continuously
System