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MELSEC-F
SETTINGS AND PROCEDURES PRIOR TO OPERATION4
4 - 14
4.7 Self-Diagnostic Tests
This section explains the self-diagnostic tests for checking the hardware and
transmission and reception function of the Ethernet module.
4.7.1 Self loopback test
The following explains the self loopback test that is used to check the hardware
including the Ethernet module's transmission and reception circuit.
The self loopback test transmits a test message within the Ethernet module to check if
the same message can be received or not. (Connection to the hub is not necessary.)
The following explains the procedure for performing the self loopback test. The test
takes approximately five seconds to complete.
The test result can be judged from the LED displays on the front of the Ethernet
module.
: Lit : Off
The following are probable causes of errors.
• Ethernet module hardware error
• Ethernet line error
An error code is stored in the error log area (BFM#229) in the buffer memory of the
Ethernet module; the error content can then be checked from GX Developer. (See
Sections 11.2 and 11.3.)
Step Description of operation
Status of LED
[RUN] [C1] [ERR.]
1
Perform a self loopback test in operation mode
( "0002
H" is written to BFM #202).
———
2
The contents of BFM#202 are written to the flash ROM
("9872
H" is written to BFM#25).
———
3
• Turn off the PLC and the Ethernet module.
• Set the RUN/STOP switch to the STOP side
• Reboot the PLC's and the Ethernet module's power.
———
4 The test is in execution.
5
The test results are shown on the LED after
approximately 5 seconds.
Normal
Error
6 Turn off the PLC and the Ethernet module. — — —