Mitsubishi Electric MELSEC iQ-R Series User Manual page 123

When the system has already operated
Problem Check item
Data link cannot B1-1 CPU module
be performed in
the entire
system.
B1-2 Power supply (for
communications)
B1-3 Cable or other
parts
B1-4 Noise
B1-5 Failure of the
master station
B1-6 Link stop
A station cannot B2-1 Power supply (for
perform data link communications)
occasionally.
B2-2 Cable or other
parts
B2-3 Noise
B2-4 Failure of a slave
station
Description Check method
Does the CPU module on the Check the error code of the CPU
master station have no error? module.
Check if the module has been
identified.
Is a voltage low? Check power supplied to the
master station and all slave
stations.
Are there no disconnection, Check if cables between the
short circuit, and poor master station and slave stations
connection? are not disconnected.
Is the transmission cable free Check if the transmission cable is
from noise? away from the power cable.
Check if the FG terminal is
grounded separated from the
GND terminal of the power
system.
Reduce the transmission speed
and check if the frequency of
occurrence of noise is reduced.
Do modules on the master Replace the modules and check if
station normally operate? the station normally operates.
Is the data link stop instruction Check if 'Data link stop' (SB0002)
correctly executed? is turned off.
Is a voltage low? Check power supplied to the faulty
station.
Are cables and connectors Check cables connected to the
securely connected and do they faulty station.
meet specifications?
When faulty stations occur
sequentially to one end on the
transmission path, check cables
connected to faulty stations close
to the master station.
Is the transmission cable free Check if the transmission cable is
from noise? away from the power cable.
Check if the FG terminal is
grounded separated from the
GND terminal of the power
system.
Reduce the transmission speed
and check if the frequency of
occurrence of noise is reduced.
Do slave stations normally Replace modules on the faulty
operate? station and check if the station
normally operates.
Action
Remove the CPU module error.
(MELSEC iQ-R CPU Module
User's Manual (Application))
Take action so that the CPU
module may identify the master/
local module. (MELSEC iQ-R
CPU Module User's Manual
(Application))
Apply the voltage within the
specified range.
Correct the wiring.
Keep the transmission cable away
from the power cable. (Keep a
distance of 100mm or more is
recommended)
Ground the terminals separately.
• Take measures to reduce noise.
• Reduce the transmission speed.
Repair or replace the module on
the master station.
• Do not turn on 'Data link stop'
(SB0002).
• Do not write to the refresh
source device of 'Data link stop'
(SB0002) from multiple
locations.
Apply the voltage within the
specified range.
Correct the wiring.
Keep the transmission cable away
from the power cable. (Keep a
distance of 100mm or more is
recommended)
Ground the terminals separately.
• Take measures to reduce noise.
• Reduce the transmission speed.
Repair or replace the module on
the faulty station.
4 TROUBLESHOOTING
4.5 Troubleshooting by Symptom
4
121