Problem Identification; Checking The Leds - Mitsubishi Electric QJ71DN91 User Manual

9 TROUBLESHOOTING

9.1 Problem Identification

This section explains checking procedures and actions to be taken when a problem
occurs.

9.1.1 Checking the LEDs

Problem occurred
Mode switch set in 0 to 8?
Yes
MS LED lit green?
Yes
NS LED lit?
Yes
NS LED lit green
or flashing green?
Yes
ERR.LED lit?
Parameter error has occurred.
Check 1B1H "Error Information for
Master Function" or 601H "Error
Information for Slave Function" in
the buffer memory for an error code,
and take corrective actions.
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No
No
No
No
NS LED lit red?
Yes
Check if:
Node No. is within the range of 0 to 63.
The same node No. exists on the network.
The same communication speed is set for
the entire network.
Terminating resistors are connected to both ends of
the trunk line.
Check for an error code.
If the above check results are normal, check the entire
network condition such as noise or installation.
No
Yes
Set Mode switch in range of 0 to 8
and reset.
(MS LED is OFF.)
Power ON the module.
Turn ON the network power (24V).
No
NS LED flashing red?
Yes
I/O communication with one or more
slave nodes has failed.
Check 1B1H "Error Information for
Master Function" or 601H "Error
Information for Slave Function"
in the buffer memory for an error code,
and take corrective actions.
Set I/O Communication Request (Y11) to ON.
MELSEC-Q
9
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