Mitsubishi Electric A1SJ71DN91 User Manual page 86

8. TROUBLESHOOTING
RUN L.RUN MS
LED LED LED LED
Green
l l
l
Green Green
NS
Status
Duplicate station number error
Red
l
Bus-off error
Online communication not
¥
established
Check item
Is a station number used for
more than one station?
Is the same baud rate set for all
stations?
Is a termination resistance
connected?
Is the communication cable
correctly connected?
Does the total cable length
exceed the permitted limit?
Reduce the total cable length.
Wrong connection type for a
slave station?
Is the slave station power
turned ON?
Is the same baud rate set for all
stations?
Is a termination resistance
connected?
Is the communication cable
correctly connected?
Does the total cable length
exceed the permitted limit?
Does the drop line length or
total drop line length exceed the
permitted limit?
Is the network power supply
correctly connected?
Is the network power supply
capacity sufficient?
Is the production inhibit time set
too short in the parameters?
Is the expected packet rate set
too short in the parameters?
Incorrect slave I/O data length
in the parameters?
l : Lit O : Not lit ¥: Flashing ¥ r: Flashing (random)  : Undetermined
−
8 7
MELSEC-A
Remedy
Correct the station numbers.
Set the same baud rate for all
stations.
Connect a termination
resistance.
Correctly connect the
communication cable.
Reduce the baud rate.
Is the network power supply
capacity sufficient?
Increase the network power
supply capacity.
Change the position of the
network power supply.
Correct the parameters.
Turn ON the slave station power.
Set the same baud rate for all
stations.
Connect a termination
resistance.
Correctly connect the
communication cable.
Reduce the baud rate.
Reduce the total cable length.
Reduce the baud rate.
Reduce the drop line length or
total drop line length.
Correctly connect the network
power supply.
Increase the network power
supply capacity.
Change the position of the
network power supply.
Correct the parameters.