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

7.9

Troubleshooting

This chapter explains troubleshooting and error codes.

Checking communication status based on LED display

Check the status of the LED display of [RD] and [SD] on the CPU module or the communication board/communication
adapter.
LED status
RD
On
On
Off
Off
When normally sending and receiving data with predefined protocol support, the LEDs both flash brightly.
If they do not flash, check the wiring and the communication settings.

Checking installation

• 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 154 Wiring)

Checking sequence program

S(P).CPRTCL instruction cannot be used in the same serial port which is being used for any other communication (such as
inverter communication instruction, RS2 instruction). (Page 236 Combined Use of Serial Communication)

Checking the communication settings

Verify that protocol type is "Predefined Protocol Support Function". When the protocol type is not "Predefined Protocol
Support Function", communication will not function correctly. (Page 191 Communication Settings)
After changing any communication setting, make sure to turn the PLC power from OFF→ON, or reset.

Checking absence/presence of errors

Serial communication error
■Error flags
If a communication error occurs in the predefined protocol support function, the serial communication error flag turns ON.
Verify that the device specified in the table below is ON.
CH1 CH2
SM8500 SM8510
7 PREDEFINED PROTOCOL SUPPORT FUNCTION
224
7.9 Troubleshooting
SD
On
Off
On
Off
CH3 CH4
SM8520 SM8530
Operation status
Data is being sent or received.
Data is being received, but not being transmitted.
Data is being transmitted, but not being received.
Data is neither being transmitted nor being received.
Name
Serial communication error
Description
Turns ON when an error occurs in serial
communication.