Troubleshooting; Checking Communication Status Based On Led Indication; Checking Installation And Wiring; Checking Sequence Program - Mitsubishi MELSEC iQ-F FX5 User Manual

3.8

Troubleshooting

This section explains troubleshooting.

Checking communication status based on LED indication

Check the status of the LED indications of [RD] and [SD] on the CPU module or the communication board/communication
adapter.
LED status
RD
On
On
Off
Off
While parallel link is executed normally, both LEDs flash brightly.
If the LEDs are not flashing, check the wiring or the master or slave station setting.

Checking installation and wiring

• Connection status
The communication cannot be operated if the PLC and the communication board/communication adapter are not connected
correctly.
For the connection procedure, refer to the following.
MELSEC iQ-F FX5U User's Manual (Hardware)
MELSEC iQ-F FX5UC User's Manual (Hardware)
• Wiring
Verify that all communication equipment is correctly wired. (Page 54 Wiring)

Checking sequence program

When the channel number that uses parallel link is specified in the instructions to be used in the inverter communication, non-
protocol communication or predefined protocol support function, some error may occur. (Page 236 Combined Use of
Serial Communication)

Checking the communication settings

Verify that the protocol type is "parallel link." When the protocol type is not "parallel link," communication will not function
correctly. (Page 57 Communication Setting)
After changing any communication setting, make sure to turn the PLC power from OFF→ON, or reset.
3 PARALLEL LINK FUNCTION
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3.8 Troubleshooting
SD
On
Off
On
Off
Operation status
The data is being sent or received.
The data is received, but is not sent.
The data is being sent, but is not received.
The data is not being sent or received.