9 Troubleshooting and Maintenance
9-56
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
Event name Remote I/O Communications Error Event code 8475 0000 hex
Meaning A timeout occurred in remote I/O communications.
Source PLC Function Module Source details CJ-series Unit Detection
timing
During DeviceNet
communications
Error attributes Level Minor fault Recovery Error reset Log category System
Effects User program Continues. Operation The DeviceNet Unit periodically performs reconnection
processing for slaves that have a remote I/O communica-
tions error. Remote I/O communications will stop, how-
ever, when a communications error occurs and remote I/O
communications are set to stop.
System-defined
variables
Variable Data type Name
None --- ---
Cause and
correction
Assumed cause Correction Prevention
The master and slaves have different
baud rates.
Correct the settings so that the mas-
ter and slaves use the same baud
rate.
Set the master and slaves to the
same baud rate.
Communications cable lengths (trunk
line and branch lines) are unsuitable.
Refer to the communications specifi-
cations and adjust all of the cables to
suitable lengths.
Refer to the communications specifi-
cations and adjust all of the cables to
suitable lengths.
A communications cable is discon-
nected or loose.
Connect the communications cable
securely. If the communications cable
is broken, replace it.
Connect the communications cable
securely. Check to see if the commu-
nications cable is operating properly.
The terminating resistance is some-
where other than the ends of the trunk
line.
Connect terminating resistance only
to the ends of the trunk line.
Connect terminating resistance only
to the ends of the trunk line.
Noise Implement noise countermeasures. Implement noise countermeasures.
Attached
information
None
Precautions/
Remarks
You can change the event level to the observation level. If you change the level to the observation level, recovery proce-
dures are not required.
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