Specifications

3 - 6
3.3.1 Self-loopback test
This test checks the hardware of a standalone network module, including the
send/receive circuit and cable of the transmission system.
(1) Connect the IN and OUT terminals of the QJ71LP21-25 network module (for the
optical loop system) with an optical fiber cable.
For QJ71LP21-25
(optical loop system)
Connect IN
and OUT
(2) Set the mode setting switch of the network module to "1".
The self-loopback test is selected.
(3) Reset using the RESET/L.CLR switch of the CPU module.
The self-loopback test is executed; check the execution status on the network
module display.
During the test, the T.PASS LED flashes and the test is determined to have
completed normally when it flashes 20 times.
If the test is abnormally completed, the ERR.LED flashes.
Before test During test Normal completion of test
T.PASS
: Off : Flashing : Normal completion of test after
20 flashes (approximately 10s)
Abnormal completion of test
ERR.
: Flashing
When an error occurs, the contents of the error should be checked with a
peripheral device. The faulty area can be examined by replacing the cable.
REMARK
In the MELSECNET/H, a link refresh is executed even when the module is offline.
Thus, the user can check the testing status and the result with a peripheral device or
a sequence program using the special link registers.
• Host communication status SW0047
1F : Offline test
• Cause of communication interruption SW0048
2 : Offline test
• Offline test status on requesting side SW00AC 7 : Self-loopback test
• Offline test results on requesting side SW00AD
0 : Normal
1 or larger : Error code
For details on how to check the error contents, refer to Appendix 5.
If two or more modules are installed, the testing status and the result of each module
can be checked by adding 200
H to the corresponding device number.