8. Troubleshooting
8.2 Fault Diagnosis
8-3 ME0342-4B
8.2 Fault Diagnosis
This section describes faults largely divided into four types as follows:
●Impossible operation of controller
●Positioning and speed of poor precision (incorrect operation)
●Generation of noise and/or vibration
●Impossible Communication.
8.2.1 Impossible Operation of Controller
Situation Possible cause Check/Treatment
LED lamps would not
turn on in green after the
power is turned on
(1) Proper power is not supplied.
(2) Servo-on command (PIO) is not
input.
1) 24V DC power for PIO is not
supplied.
2) Poor contact of flat cable
3) The operation mode setting
switch on the front panel is on
“MANU” side.
(3) Occurrence of alarm. (Illuminated in
red)
(4) During emergency-stop. (Illuminated
in red)
1) Was the emergency-stop switch.
2) EMG- on the power supply
connector is not connected.
(1) Ensure that appropriate voltage
is supplied and the wiring is in
the right condition.
Refer to [3.3.1 Wiring Layout of
Power Supply Connector.]
(2) 1) Check the PIO power voltage.
When a large load is applied
to one power source, there is
a risk of power voltage drop
or a shutdown of the output.
2) Are the PIO cable connectors
inserted to the mating
connectors securely? Check
the input signals on the I/O
monitor of the teaching tool
such as PC software.
Caution
In I/O cable conduction check,
do not widen female pins of the
connectors. Failure to follow this
3) Can such operation as
jogging be performed from
the teaching tool such as PC
software? Set the operation
mode setting switch on the
front panel and restart the
controller.
Refer to [1.3 Name for Each
Parts and Their Functions.]
(3) Check the error code with the
teaching tool being connected
and remove the cause by
referring the alarm list.
Refer to [8.3 About Alarms]
(4) 1) Release the emergency stop
switch.
2) Check the connection of the
power connector (EMG-).
Refer to [3.3.1 Wiring Layout
of Power Supply Connector.]
8.2 Fault Diagnosis
ME0342-4B 8-4
Situation Possible cause Check/Treatment
ALM in the status display
LEDs turns on when the
power is supplied.
(2) During emergency-stop.
1) Was the emergency-stop switch.
2) EMG- on the power supply
connector is not connected.
(1) Check the error code with the
teaching tool being connected
and remove the cause by
referring the alarm list.
Refer to [8.3 Alarm List.]
(2) 1) Release the emergency stop
switch.
2) Check the connection of the
power connector (EMG-).
Refer to [3.3.1 Wiring Layout
of Power Supply Connector.]
The host controller (PLC)
cannot control PIO (24V
I/O).
PIO signal communication is disabled.
1) 24V DC power for PIO is not
supplied.
2) Poor contact of flat cable
3) The operation mode setting switch
on the front panel is on “MANU”
side.
4) The +/- pins of 24V DC power for
PIO are connected inversely.
1) Check the PIO power voltage. If
a single power supply is
connected with large load, the
power supply voltage may drop
or the output may be shut down
depending on power units.
2) Are the PIO cable connectors
inserted to the mating
connectors securely? Check the
input signals on the I/O monitor
of the teaching tool such as PC
software.
Caution
In I/O cable conduction check,
do not widen female pins of the
connectors. Failure to follow this
3) Can such operation as jogging
be performed from the teaching
tool such as PC software? Set
the operation mode setting
switch on the front panel and
restart the controller.
Refer to [1.3 Name for Each
Parts and Their Functions.]
4) Reverse connection of the PIO
power supply does not affect the
input circuit but makes the
output circuit faulty. Check if the
I/O of the host controller (PLC)