Troubleshooting - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
Computer Link
8.

Troubleshooting

This chapter explains troubleshooting.
8.1 Checking FX PLC Version Applicability
Verify that the FX PLC main unit is an applicable version.
8.2 Checking Communication Status Based on LED Indication
Check the status of the "RD(RXD)" and "SD(TXD)" indicator LEDs provided in the optional equipment.
LED status
RD(RXD)
Flashing
Flashing
Off
Off
While computer link is executed normally, both LEDs flash brightly.
If they do not flash, check the wiring, station number settings and communication setting.
8.3 Checking Installation and Wiring
1. Mounting status
If the communication equipment is not securely connected to the PLC, communication is not possible.
2. Power supply (for FX
The FX -485ADP requires a driving power supply. Verify that the power supply is provided correctly.
0N
3. Wiring
Verify that the wiring to all communication equipment is correct. If the communication equipment is wired
incorrectly, communication is not possible.
8.4 Checking Sequence Program
1. Communication setting in the sequence program
Verify that the parallel link and N:N Network are not set. Verify that the communication format (D8120, D8400
and D8420) is set correctly. Communication is not possible if a communication port is set twice or more.
After changing any setting, make sure to reboot the PLC's power.
2. Communication setting using parameters
Verify that the communication settings using parameters is suitable to the purpose of use.
If the communication settings are not suitable to the purpose of use, communication will not function correctly.
After changing any setting, make sure to reboot the PLC's power.
3. Ethernet port setting (in FX
Verify that the same channel is not used in the Ethernet port setting. Do not set the channel used in computer link.
After changing the setting, make sure to reboot the PLC's power.
D-86
SD(TXD)
Flashing Data is being sent or received.
Off Data is received, but is not sent.
Flashing Data is sent, but is not received.
Off Data is not sent or received.
For mounting method, refer to the respective communication equipment manual.
-485ADP)
0N
, FX , FX
3S 3G
For the version applicability check, refer to Section 1.3.
Operation status
For wiring method check, refer to Chapter 4.
, FX and FX
3GC 3U 3UC
8 Troubleshooting
8.1 Checking FX PLC Version Applicability
PLCs)