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MELSEC-Q
4 SETTINGS AND PROCEDURES PRIOR TO OPERATION
(Procedure 4) Checking the results of an individual loopback test
(1) This test is performed repeatedly. When the ERR LED is off, the test is being
executed normally.
(2) The test is completed with an error when the ERR LED is lit. Check the error
description on one of the following screens. (The ERR LED is lit upon error
occurrence, and the test is completed.)
• The "Monitor/test others" screen of GX Configurator-SC (see Section 8.6.9)
• The buffer memory monitor screen of GX Developer (see the GX Developer
Manual for operation method)
When checking for errors in the buffer memory monitor screen of GX
Developer, monitor the LED ON status storage area (address CH1: 201
H
,
CH2: 202
H
).
Check the error descriptions on the screens by bit-decoding the monitored value
(16-bit integer). Each bit corresponds to the following error description.
Buffer memory monitored
Address
Bit location
CH1 side
201
H
CH2 side
202
H
Description when corresponding
bit is on
Corrective action
b0 to b3 — — —
Error occurrence in the CPU module.
Remove errors occurring in the CPU
module.
Not enough power supply capacity. Examine the power supply capacity.
Module is not mounted correctly. Reinstall the module properly.
b4 C/N —
Error occurrence in the base unit,
extension cable, CPU module, or the
Q series C24.
Check each module and remove the
cause of the error.
Reconnect the cable correctly.
Reinstall the module correctly.
b5 to b13 — — —
b14 CH2 ERR CH2 side communication error
b15
—
CH1 ERR CH1 side communication error
Reconnect the cable correctly.
Examine the test wiring connection.
(Procedure 5) Ending individual station loopback test
(1) Perform the following procedures after checking normal completion/abnormal
completion of the test result.
Normal completion : Perform operation (2) to finish the test.
Upon error occurrence : Remove the cause of the error according to the corrective
action specified in the table above, and test again.
(2) Perform the ending procedure for individual station loopback test
1) Follow the procedure in Section 4.7.1 to perform a ROM/RAM/switch test.
2) Perform the following procedure to end the test and start data communication
with an external device.
• Set the switch settings on GX Developer according to the procedure
specified in Section 4.5.2.
• Turn off the power to the station on which the Q series C24 is installed and
connect the communication cable with the external device.
• Turn on the power to the station on which the Q series C24 is installed.