Mitsubishi Electric A1SJ71DN91 User Manual page 82

8. TROUBLESHOOTING
Symptom
No Communication With
Slave Stations After A
Certain Station
No Communication With A
Certain Station
Check Item
Is the power supply connected to that station?
Is the network power supply capacity sufficient?
Is the position where the network power supply is connected
OK?
Determine whether the network power supply is connected
to a suitable position, referring to 5.6 Instructions for
Connecting the Network Power Supply.
Is the communication cable correctly connected to that slave
unit (no discontinuity)?
Are the slave stations set in the parameters?
Is a termination resistance correctly connected to each end
of the network?
Is the same baud rate set for each station?
Does the cable length exceed the permitted limit?
Check the cable length restrictions appropriate for the cable
thickness and baud rate, referring to 3.2 Performance
Specifications.
Check the parameter settings.
Check the error codes.
See 8.3 Troubleshooting using Error Codes.
Is the power supply connected to that station?
Is the network power supply capacity sufficient?
Is the position where the network power supply is connected
OK?
Determine whether the network power supply is connected
to a suitable position, referring to 5.6 Instructions for
Connecting the Network Power Supply.
Is the communication cable correctly connected to that slave
unit?
Is the slave station set in the parameters?
Is the slave station set as a reserved station in the
parameters?
Does any slave station have the same station number as
another slaves station?
Station number in the parameters differs from the station
number of the actual slave station.
Do the I/O data length and I/O communication connection
type in the parameters match those of the actual station?
−
8 3
MELSEC-A
Remedy
Turn ON the slave station power supply.
Replace with a power supply of larger
capacity.
Add a power supply.
Reduce the network load.
Change the position where the network
power supply is connected.
Correctly connect the cable.
Set the slave stations in the parameters.
If a station is set as a reserved station,
change the parameter setting to actively
communicating station.
Check if termination resistances are
connected and if they are connected
correctly.
Make sure that the same baud rate is set
for each station.
Reduce the cable length.
Reduce the baud rate.
If thin cable is used in the trunk line,
replace it with thick cable.
See 8.1.2 Problems Due to Incorrect
Parameter Settings
Take the remedy described for the error
code.
Turn ON the slave station power supply.
Replace with a power supply of larger
capacity.
Add a power supply.
Reduce the network load.
Change the position where the network
power supply is connected.
Correctly connect the cable.
Set the slave station in the parameters.
Change the slave station from a
reserved station to an actively
communicating station.
Set the station numbers to avoid
duplication.
Set the station number in the parameters
to match the station number of the actual
slave station.
Set the I/O data length and I/O
communication connection type in the
parameters to match those of the actual
station.