Mitsubishi Electric MELDAS C6 Instruction Manual page 400

(3) Problems related to remote I/O
The communication alarm LED ALM (red) lights.
The power system LED POWER (green) turns OFF.
(4) Problems related to Ethernet
A communication error message is appeared on the display, and the communication LEDs RX (green)
and TX (green) turn OFF.
In other cases, a communication error message is appeared on the display, and after the OK button is
pressed, the communication error message appears again and the communication LEDs RX (green)
and TX (green) turn OFF.
CAUTION
Do not apply voltages other than those indicated in the Connection and Maintenance Manual on
the connector. Doing so may lead to destruction or damage.
Incorrect connections may damage the devices, so connect the cables to the specified connectors.
Do not connect or disconnect the connection cables between each unit while the power is ON.
Do not connect or disconnect the PCBs while the power is ON.
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Cause
The remote connection cable is
not connected.
The cable is disconnected or has
a connector contact fault.
The remote I/O unit is faulty.
Cause
The input power is not being
supplied.
(The input power is not within the
tolerable range, or the internal
power is faulty.)
Cause
The Ethernet cable is not
connected, is broken, or there is
a contact fault at the connector.
A straight type Ethernet cable is
in use.
The Ethernet unit is not inserted
to the very back.
The Ethernet unit is faulty.
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8. Fault Diagnosis and Action
8.2 Fault Examples
Check the connection of the R211 cable between the NC
control section and remote I/O unit.
Contact the Mitsubishi Service Center, and then replace
the card.
Supply a +24V±5% voltage to the Remote I/O unit.
Check that the input voltage is not +20V or less. If it is
being supplied correctly, contact the Mitsubishi Service
Center.
Check the cable connected between the NC control unit
and display.
Use a cross type Ethernet cable.
Insert the Ethernet unit so that the plate is flush with the
front panel.
Contact the Mitsubishi Service Center and replace the unit.
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Remedy
Remedy
Remedy