The L Err. Led Is On Or Flashing - Mitsubishi Electric MELSEC Q Series User Manual

6.3.4
Check the following.
(1) The L ERR. LED is on
The test mode switch is on.
A remote station is connected outside the control range.
A faulty remote station is detected by Faulty station
information (buffer memory address: 4 to 7 (Un/G4 to 7)).
(
A communication cable is incorrectly wired.
*1
If the L ERR. LED remains on even after the above actions are taken, the possible cause is a hardware failure.
Please consult your local Mitsubishi service center or representative, explaining a detailed description of the
problem.
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The L ERR. LED is on or flashing

Check item
Page 31, Section 3.3.2)
Check for short circuit, reverse connection, disconnection, excessive pressure, terminating resistors, overall cable
distance, branch line distance (overall branch line length, maximum branch line length), and surrounding environment
such as a noise.
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Action
Please consult your local Mitsubishi service center or
representative, explaining a detailed description of the
problem.
• Remove the remote station connected outside the control
range.
• Increase the number of occupied I/O points.
• Set a greater value for the last station number.
After taking the above actions, power off and on the system
or reset the CPU module.
Troubleshoot the faulty remote station.
Remote I/O station: Page 70, Section 6.4
Remote device station: User's manual for the remote
device station used
*1
Correct the wiring.
( Page 49, Section 4.5)