SMC Networks ex250-sen1 Operation Manual page 24

Trouble No.5
Trouble Possible cause
Failure of the power
supply for the input
and control of the SI
unit.
Incorrect connection
between the SI unit
and input block
The Input
block
PWR_LED
The Input block fuse
goes off.
has melted
Intrusion of liquids
such as water
Input block failure
Trouble No.6
Trouble Possible cause
Inconsistent polarity
in sensors
Only the input
signal LED of
Incorrect connection
the Input block
of the sensor
do not lights
up
Sensor failure
Trouble No.7
Trouble Possible cause
Incorrect wiring of the
power supply for the
The SI unit
input and control
PWR_LED
goes off.
Failure of the power
supply for the input
and control
Investigation method of cause
Check the supply voltage to the power
supply for the input and control of the SI
unit.
Check that the bolt joining the SI unit and
Input block has not loosened.
Check if the fuse of the input block has
melted.
Check that unused connectors of the Input
block are plugged with waterproof caps.
Replace the Input block with new one and
operate to check the normal operation
recovers.
Investigation method of cause
Check the specifications of the Input block
(NPN, PNP) match those of the sensor.
Check that the sensor cable is not broken
and that the connection between the sensor
cable and connector has not loosened.
Check the troubleshooting of the sensor.
Investigation method of cause
Check that the power supply cable for the
input and control is not broken, and that the
connection between the power supply cable
and connector has not loosened.
Check that there is no incorrect wiring of
the power supply cable.
Check the supply voltage to the power
supply for the input and control.
-23-
Remedy
Supply 24 VDC ±10% to the
power supply for the input
and control.
Tighten the bolts by hand so
that there is no gap between
the SI unit and Input block.
Tighten at the specified
torque.
(Tightening torque: 0.6 Nm)
Remove the cause of the
short-circuit and replace the
fuse with new one.
If liquid such as water has
got into the input, replace the
Input block with new one.
Replace the Input block with
new one.
Remedy
Make a suitable combination
of Input block and sensor.
Review the connection
condition of the sensor cable.
(If the cable is broken,
replace it with new one.)
Correct the trouble of the
sensor.
Remedy
Review the connection
condition of the power supply
cable. (If the cable is broken,
replace it with new one.)
Review the wiring condition
of the power supply cable.
Supply 24 VDC ±10% to the
power supply for the input
and control.
No.EX##-OMK0004-A