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CHAPTER 12 TROUBLESHOOTING
12
12.3 Checking the LEDs
(6) The L ERR. LED turns on
If the above actions do not solve the problem, follow the directions shown in "Communication is unstable".
( Page 245, Section 12.4.6)
(7) The LINK LED turns off
If the above actions do not solve the problem, perform the following tests on the master/local module to check for an
error.
• Hardware test ( Page 60, Section 6.2.1)
• Self-loopback test ( Page 62, Section 6.2.2)
• Cable test ( Page 74, Section 6.4.2)
Check item Action
Are the Ethernet cables operating normally?
• Check if 1000BASE-T-compliant Ethernet cables are used.
( Page 33, Section 3.2)
• Check if the station-to-station distance is 100m or less.
( Page 66, Section 6.3 (2))
• Check if the Ethernet cables are not disconnected.
Is the switching hub operating normally?
• Check if a 1000BASE-T-compliant switching hub is used.
( Page 57, Section 5.2.2)
• Check if the switching hub is on.
Are other stations connected to the master/local modules
operating normally?
Check if the systems on other stations are on.
Is the master station set to online mode?
Change the mode of the module to Online. ( Page 79, Section 7.2)
Is there any noise affecting the system? Check the wiring condition.
Is the loopback function enabled for the master station?
When the loopback function is enabled, check if the ring topology is
correctly configured for the port where the L ERR. LED is on.
( Page 47, Section 5.1.1)
Check item Action
Are 1000BASE-T-compliant Ethernet cables used?
Replace the cables with 1000BASE-T-compliant Ethernet cables.
( Page 56, Section 5.2.1)
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 the switching hub and other stations connected to the
master/local module normal?
Power on the switching hub and the other stations.