Input Data Cannot Be Read From A Remote I/O Station; Data Cannot Be Output From A Remote I/O Station - Mitsubishi Electric MELSEC Q Series User Manual

6.4.4
Check the following.
The master station does not recognize the relevant remote
I/O station. (
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.
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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.
6.4.5
Check the following.
The master station does not recognize the relevant remote
I/O station.
(
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
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.
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Input data cannot be read from a remote I/O station

Check item
Page 74, Section 6.6)
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.

Data cannot be output from a remote I/O station

Check item
Page 74, Section 6.6)
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
Correct the wiring of the communication cable.
( Page 49, Section 4.5)
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 49, Section 4.5)
Correct the address.
Correct the wiring.
*1
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