Troubleshooting - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
N:N Network
9.

Troubleshooting

This chapter explains troubleshooting.
9.1 Checking FX PLC Version Applicability
Verify that the FX Series PLC main unit is an applicable version.
9.2 Checking Communication Status Based on LED Indication
Check the status of the "RD" and "SD" indicator LEDs provided in the optional equipment.
LED status
RD
Flashing
Flashing
Off
Off
While the N:N Network is executed normally, both LEDs flash brightly.
If they do not flash, check the wiring and the communication setting in the master and slave stations.
9.3 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 correctly provided.
0N
3. Wiring
Verify that the wiring to all communication equipment is correct. If the communication equipment is wired
incorrectly, communication is not possible.
9.4 Checking Sequence Program
1. Communication setting in the sequence program
Verify that the parallel link is not set. Using both the parallel link and the N:N Network at the same time is not
allowed.
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 are suitable for use. Do not set parameters for the
N:N Network. If the communication settings are not suitable for use, communication will not function correctly.
After changing the setting, make sure to reboot the PLC's power.
B-48
SD
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 nor received.
For mounting method, refer to the respective communication equipment manual.
-485ADP)
0N
For the version applicability check, refer to Section 1.3.
Operation status
For wiring method check, refer to Chapter 4.
For communication setting, refer to Chapter 5.
For the communication setting, refer to Chapter 5.
9 Troubleshooting
9.1 Checking FX PLC Version Applicability