Mitsubishi Electric MELSEC L Series User Manual page 95

(8) When the L ERR. LED turns on
Are the Ethernet cables correctly used and connected?
Is the switching hub used in the system operating normally?
Are other stations connected to the head module operating normally? Check the operating status of modules on other stations.
Is the mode of the module on the master station set to Online?
Is there any noise affecting the system?
Is the loopback function enabled for the master station?
If the above actions do not solve the problem, perform the following tests on the head module to check for an
error.
• Unit test (
• Cable test (
(9) When the LINK LED turns off
Are the Ethernet cables correctly used and connected?
Does the cabling condition (bending radius) meet the
specifications?
Are the switching hub and other stations connected to the head
module operating normally?
If the above actions do not solve the problem, perform the following tests on the head module to check for an
error.
• Unit test (
• Cable test (
(10)When the REM. LED flashes
After execution of the write to PLC function, was the head
module reset?
Are any forced I/O data being registered?
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Page 45, Section 6.4)
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• Check if 1000BASE-T-compliant Ethernet cables are used.
( Page 26, Section 3.2)
• Check if the station-to-station distance is 100m or less. (
Page 50, Section 6.5.3)
• Check if the Ethernet cables are not disconnected.
• Check if a 1000BASE-T-compliant switching hub is used. (
User's manual for the master/local module used)
• Check if the switching hub is powered on.
Change the mode to Online. (
master/local module used)
Check the wiring condition.
When the loopback function is enabled, check if the ring topology
is correctly configured for the port where the L ERR. LED is on.
( User's manual for the master/local module used)
• Check if 1000BASE-T-compliant Ethernet cables are used. (
Page 26, Section 3.2)
• Check if the station-to-station distance is 100m or less. (
50, Section 6.5.3)
• Check if the Ethernet cables are not disconnected.
Refer to the manual for the Ethernet cable used, and correct the bending
radius to meet the specifications.
Check if the switching hub and other stations are powered on.
Reset the head module.
Cancel the registration.
CHAPTER 11 TROUBLESHOOTING
Action
User's manual for the
Action
Action
11
Page
93