Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 140

4 SETUP AND PROCEDURES BEFORE STARTING THE OPERATION
Switch position
Display section
Switch position
Display section
4 - 34
(4) Checking the test result
The T.PASS LED of the network module flashes at approximately 0.5 s intervals.
When the T. PASS LED flashes 20 times (approx. 10 seconds)
the ERR.LED does not flash, this condition indicates normal completion.
When the test has failed, the ERR. LED flashes.
[Normal test result]
Before test
(during RESET)
RUN
MNG
T.PASS
D.LINK
SD
RD
ERR.
L ERR.
[Abnormal test result]
Before test
(during RESET)
RUN MNG
T.PASS D.LINK
SD RD
ERR. L ERR.
Upon detection of an error, the test will be terminated (abnormal termination).
1: For the twisted bus system, the test is conducted at 156kbps and eight
minutes is required for the test.
If the ERR. LED does not flash after the eight minutes, the test has
completed normally.
(a) Possible causes of errors in the optical loop system
1) Forward loop error
• The cable of the forward loop is disconnected.
• The sending and receiving stations of the forward loop are not
connected with a cable.
• The sending stations of the forward and reverse loops, or the
receiving stations of the forward and reverse loops are connected.
2) Reverse loop error
• The cable of the reverse loop is disconnected.
• The sending and receiving stations of the reverse loop are not
connected with a cable.
3) Defective cable
4) The cable was disconnected or broken during the test
5) Hardware error
(b) Possible causes of errors in the coaxial/twisted bus system
1) The cable is broken or defective
2) The cable was disconnected or broken during the test
3) A terminating resistor was detached
4) Hardware error
5) Incorrect wiring (For the twisted bus system)
During test
(during STOP)
RUN
MNG
T.PASS
D.LINK
SD
RD
ERR.
L ERR.
Or L. ERR.
During test
(during STOP)
RUN MNG
T.PASS D.LINK
SD RD
ERR. L ERR.
Or L. ERR.
MELSEC-Q
1
or more and if
Test complete
Complete when
T.PASS flashed 20 times
(approx. 10 seconds) or more.
1
Test complete
Flashing of the ERR.
LED indicates an error.
4 - 34