Checking Online For Reverse Optical Fiber Cable Connection - Mitsubishi Electric Q Series Reference Manual

8 TROUBLESHOOTING

8.2.9 Checking online for reverse optical fiber cable connection

Start
Check the loopback information
(SW0090) of the host station.
Are the loops normal?
(Is the SW0090 value 0?)
Yes (0)
Check the loop using status of each
station (SW009C to SW009F).
Are all bits of SW009C to
SW009F OFF or ON?
Yes
The cables are connected normally
to all stations.
End
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This section explains the checking procedure for incorrect optical fiber cable
connection (IN-IN, OUT-OUT) during online and the link special registers (SW009C to
SW009F) used for the check.
Unlike the loop test, the checking procedure given in this section allows a check
without stopping a data link.
If incorrect cable connection is found, correct the wiring after shutting off all phases of
the system.
POINT
Before starting the check given in this section, make sure that the following
conditions are satisfied.
If these are not satisfied, conduct a loop test to make a check.
The optical fiber cables have no breaks. (Both the forward and reverse loop
cables are normal.)
There are no stations having data link error (power off, MELSECNET/H module
failure).
(1) Checking procedure
Follow the procedure given below to check for incorrect optical fiber cable
connection (IN-IN, OUT-OUT) during online.
No
(Other than 0)
No
Conduct a loop test to identify the faulty portion, and change the cable.
1) The bit of only one station is ON or OFF.
<Cause>
The cable of the station whose bit is ON is incorrectly connected
(IN-IN, OUT-OUT).
<Corrective action>
Check the cable connection status of the station whose bit is ON.
2) The bits of multiple stations are ON or OFF.
<Cause>
The cables of the stations whose bits are ON are incorrectly
connected (IN-IN, OUT-OUT).
<Corrective action>
Check the cable connection status of the stations whose bits are ON.
3) The bits of all stations except for the host station are ON or OFF.
<Cause>
The cable of the host station is incorrectly connected
(IN-IN, OUT-OUT).
<Corrective action>
Check the cable connection status of the host station.
MELSEC-Q
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