I/O Errors In Remote I/O Stations; Input Data Cannot Be Read From A Remote I/O Station; Data Cannot Be Output From A Remote I/O Station - Mitsubishi Melsec-L Series User Manual

8.5

I/O Errors in Remote I/O Stations

This section describes troubleshooting on I/O errors in remote I/O stations.
8.5.1

Input data cannot be read from a remote I/O station

Check the following:
The master station does not recognize the relevant remote
I/O station.
( Page 63, Section 8.7)
The input LED of the relevant remote I/O station is not on.
An incorrect remote input address is specified.
A station number is duplicated.
*1 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.
If input data cannot be read from the remote I/O station 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.
8.5.2

Data cannot be output from a remote I/O station

Check the following:
The master station does not recognize the relevant remote
I/O station.
( Page 63, Section 8.7)
The output LED of the relevant remote I/O station is not on.
Wiring between the remote I/O station and the external
device is incorrect.
*1 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.
If data cannot be output from the remote I/O station 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.
Check item
Check item
CHAPTER 8 TROUBLESHOOTING
Action
Correct the wiring of the communication cable.
( Page 36, Section 6.3)
Correct the wiring between the remote I/O station and the
external device.
Correct the address.
Correct the station number.
After changing a remote station number, power off and on
the system.
Action
Correct the wiring of the communication cable.
( Page 36, Section 6.3)
Correct the address.
Correct the wiring.
*1
8
*1
61