Mitsubishi Electric MELSEC iQ-R Series User Manual page 121

Problem Check item
Data link A3-1 Cable or other
cannot be parts
performed in
the entire
A3-2 Parameter
system
setting
occasionally.
A3-3 Power supply (for
communications)
A3-4 Noise
A3-5 Failure of the
master station
A3-6 Link stop
Description
Are cables and connectors
securely connected and do they
meet specifications?
Is the sequence scan long?
(Synchronous mode)
Is the power on, and is the applied
voltage within the specified
range?
Is the transmission cable free from
noise?
Do modules on the master station
normally operate?
Is the data link stop instruction
correctly executed?
Check method
Check cables between the master
station and slave stations.
Check if the sequence scan time is
within the range.
10Mbps: 50ms
5Mbps: 50ms
2.5Mbps: 100ms
625kbps: 400ms
156kbps: 800ms
Check power supplied to the master
station and all slave stations.
Check if the transmission cable is
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.
Replace the modules and check if the
station normally operates.
Check if 'Data link stop' (SB0002) is
turned off.
4.5 Troubleshooting by Symptom
Action
Correct the wiring.
Set the asynchronous mode or
reduce the transmission speed.
Apply the voltage within the
specified range.
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.
4 TROUBLESHOOTING
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