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431
CHAPTER 12 TROUBLESHOOTING
12
12.
3
C
hecking t
he LEDs
(3) When the D LINK LED turns off or is flashing
Check item
Action
Is the master station connected to the network and operating
normally?
• If an error has occurred in the CPU module of the master station,
remove the cause of the CPU module error. (
12.2)
• Connect GX Works2 to the master station. Check if the master station
is performing data link using CC-Link IE Field Network diagnostics,
and take action. (
When the master station and submaster station are the module of the
MELSEC-Q series, and there is a local station of the MELSEC iQ-R
series module, refer to the following.
(
Are 1000BASE-T-compliant Ethernet cables used?
Replace the cables with 1000BASE-T-compliant Ethernet cables.
(
Is the station-to-station distance 100m or less?
Change the station-to-station distance to 100m or less.
Does the cabling condition (bend radius) meet the
specification?
Refer to the manual for the Ethernet cable, and correct the bend radius.
Is any Ethernet cable disconnected?
Replace the Ethernet cable.
Are 121 or more slave stations connected?
Change the connection of the slave stations to 120 stations or less.
Is the loopback function enabled for the master station?
Configure the network in ring topology without a switching hub.
Are other stations connected to the master/local modules
operating normally?
Power on the other stations.
Is the switching hub operating normally?
• Check if a 1000BASE-T-compliant switching hub is used.
(
• Power off and then on the switching hub.
Check that the cables are not connected as described below.
• Both PORT1 and PORT2 are connected to a switching hub.
• Although the loopback function is disabled, the network is
configured in ring topology.
• Although the loopback function is enabled, the network is
configured in star topology.
• The network is incorrectly configured in ring topology.
• Correct the wiring. (
• If the system does not contain a switching hub.
• If the system contains a switching hub.
Is the station number of the master/local module duplicated with
any of the other stations?
Change the duplicated station number.
• When not using the loopback function
Disconnect an Ethernet cable connected to any station on the
network (either PORT1 or PORT2).
The network topology will become a line topology and data link will
start.
• When using the loopback function
Enable the loopback function and rewrite the network parameter to
the CPU module.
(
1.
Check if the loopback function setting is correctly configured.
(
If incorrect, correct the network parameter and rewrite it to the
CPU module. When data link starts across the entire network, this
procedure is successful.
2.
Disconnect one Ethernet cable connected to the switching hub
and power off and then on the hub. (Repeat this operation until
data link starts over the network.)
3.
When data link starts over the network, check the network
configuration by CC-Link IE Field Network diagnostics.
(