Mitsubishi Electric MELSEC QS Series User Manual page 138

9
TROUBLESHOOTING
Description of problem
Is the number of
connected remote stations
within the allowable
range?
Is the terminal block or
connector for T-branch
system correctly
connected? (If the module
is used in the T-branch
system.)
A remote station is not
Is the terminating resistor
started.
connected to the correct
location? (If a repeater is
used.)
Is there any breakage on
CC-Link dedicated
cables?
Unable to detect a faulty Isn't the station number
station. overlapped?
If the transmission speed
is reduced to a lower level
An error is generated on a
such as 156 kbps, can
station depending on the
communication be
transmission speed.
performed without an
error?
Is there any fault in the
A remote device station is program for the remote
not operating normally. device station's initial
setting?
9
- 8 9.1 Checking the Condition by Each Problem
Check item Check procedure
Check if it is within the
allowable range or not
referring to Section 2.1
Overall Configuration.
Visually check the
connection of the terminal
block or connector for T-
branch system.
Check if the terminating
resistor is connected to
the correct location.
Check the CC-Link
dedicated cables (for
breakage, short-circuit,
incorrect wiring, poor
contact or
nonconformance) visually
or by the CC-Link
diagnostics line test.
Check the parameters.
Change the transmission
speed to 156kbps in
network parameters, and
check the communication
status by the other station
monitor of the CC-Link
diagnostics.
Check the sequence
program.
Check result
The number of connected Reduce the number of
remote stations is connected remote
exceeding the limit. stations.
The number of connected
remote stations is within Check other items.
the allowable range.
The terminal block or Correctly connect the
connector for T-branch terminal block or
system is incorrectly connector for T-branch
connected. system.
The terminal block or
connector for T-branch
Check other items.
system is correctly
connected.
The terminating resistor is Connect the terminating
connected to an incorrect resistor to the correct
location. location.
The terminating resistor is
connected to the correct Check other items.
location.
Remove the cause of the
A cable fault is found. fault and correct the
connection.
Check other items. If all
the check results are
normal, a hardware fault
of the safety master
No cable fault is found.
module or the remote
module may be probable.
Contact your local
Mitsubishi representative.
The station No. is Correct the station No.
overlapped. setting.
The station No. is not
Check other items.
overlapped.
Communication is Modify the transmission
performed normally. speed setting.
Change the transmission
A communication error speed in network
occurs. parameters again, and
check the result.
A fault is found in the Modify the sequence
sequence program. program.
There is no fault in the
Check other items.
sequence program.
Corrective action