Mitsubishi Electronics QJ71DN91 ユーザーズマニュアル

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MELSEC-Q

9 TROUBLESHOOTING

9.1 Items to Check When an Error Occurs

This section explains the items to check when an error occurs and its troubleshooting

procedure:

9.1.1 Checking the LEDs

Is the NS LED lit in green

or flashing in green?

Occurrence of an error

Is the mode switch set

between 0 and 8?

Reset by setting the mode switch between
0 and 8.

Yes

Is the MS LED lit in green?

(The NS LED is off.)
Turn ON the module power.

Is the NS LED lit?

Turn ON the network power (24V).

Is the NS LED lit in red?

Check the following:
•   Is the node number between 0 and 63?
•   Does a duplicate node number exist within
  the network?
•   Is the communication speed uniform in the
  entire network?
•   Is a terminal resistor installed at both ends of
  the trunk line?

Check the error code.

If all of the above check items are normal, check
the entire network status such as noise and installation.

Is the ERR. LED lit?

Turn ON the "I/O communication request" (Y11).

Is the NS LED flashing in red?

An I/O communication error has
occurred with one or more slave stations.
Check the error code with 1B1

master function for error information
function" and 601

, "slave function for error

information" of the buffer memory,
and take an appropriate action.

A parameter error has occurred.
Check the error code with 1B1

"master function for error information"
and 601

, "slave function for error

information" of the buffer memory,
and take an appropriate action.

Yes