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MELSEC-Q
6 PRE-OPERATIONAL PROCEDURES AND SETTING
6.5.2 Self-loopback test
This section explains the self-loopback test conducted to check the QJ71MT91
hardware including the send/receive circuits.
The procedure for the self-loopback test is shown below.
This test is run for about 5 seconds.
The test result can be checked with the LEDs on the front of the QJ71MT91.
LED Status
Step Operation
[RUN] [OPEN] [ERR.]
1
STOP the programmable controller CPU.
Disconnect the network cable from the QJ71MT91.
2
In the intelligent function module switch setting of GX
Developer, set Switch 1 to 000E
H
to select the self-
loopback test mode. (Refer to Section 6.6.)
3
Reset the programmable controller CPU. (Test start)
Normal
4
After 5 seconds, check the status of each
LED.
Error
5
When the self-loopback test is completed, change the
operation mode to "Online" or another mode in the
intelligent function module switch setting.
6
Reset the programmable controller CPU.
: ON
: OFF
: A possible cause of error is the hardware fault of the QJ71MT91.
When an error occurs, the error code is stored into the error log area (address: CFE
H
to
CFF
H
) of the buffer memory in the QJ71MT91.
Using GX Developer, confirm the error code and take corrective action.
(Refer to Section 11.2 and 11.3.)
POINT
When the self-loopback test results in an error, run the test again.
If the error occurs again, its possible cause is the hardware fault of the QJ71MT91.
Please consult your local Mitsubishi service center or representative, explaining a
detailed description of the problem.
