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6. TROUBLESHOOTING MELSEC-A
6-2
6.2.1 When a communication fault occurs between the master station and this
module
If the station-number-overlapping bit is turned on in the link special resister SW0098 to SW009B
(station number overlapping status), check the AJ65BT-64DAV/DAI module of the corresponding
station number by following the flow shown below:
"ERR" LED of the
master station flashes
Do the parameter
settings match the actual
system configuration?
Is the link special
register SW0080 to SW0083
(data link status of other stations)
of the master station
turned on?
Link special
register SW0098 to SW009B
(station number overlapping status)
of the master station
Check the module whose SW0098
to SW009B is turned on.
Is the station number
switch properly set?
Breakdown of the
corresponding module
Correct parameter setting
or the actual system
configuration.
Breakdown of the
master station
Set the station number
switch correctly.
Turn on the power again.
Turn on the reset switch.
Check the module whose SW0080
to SW0083 is turned on.
Is the power
turned on?
Is the
"POWER" LED
turned on?
Is the "RD" LED
turned on?
Is the "L RUN"
LED turned on?
Is the
"SD" LED turned on
(flashing)?
Is the station
number switch set correctly?
(Is it overlapping another
station?)
Breakdown of the corresponding
module (station number switch)
Check the master side.
Check the slave station side.
Turn on the power.
Is the
supplied voltage
within the specified
range?
Adjust the supplied voltage
to within the specified range.
Breakdown of the
corresponding module
Is the
communication cable
wired correctly?
*1
Breakdown of the
corresponding module
Wire the communication
cable correctly.
Is the "SD"
LED turned on
(flashing)?
Breakdown of the
corresponding
module
Is the baud rate
setting correct?
Is the
communication cable
wired correctly?
*1
Set the baud
rate correctly.
Turn on the power again.
Turn on the reset switch.
Wire the communication
cable correctly.
Breakdown of the
corresponding module
(baud rate switch)
Is the station
number switch set correctly?
(Is it overlapping another
station?)
Set the station
number correctly.
Breakdown of the corresponding
module (station number switch)
Set the station
number correctly.
End
*1 Check the following: short-circuit,
reversed connection, cable breakage,
terminal resistor, FG connection, total
distance, and the distance between
stations.
Y
N
Y
Y
YY
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
Troubleshooting flow when the ERR LED on the master station is flashing
Turn on the power again.
Turn on the reset switch.
Turn on the power again.
Turn on the reset switch.
6