SMC Networks EX600-SEC Series Operation Manual page 39

No. Problem
Abnormal digital input
device operation
15
Abnormal digital output
device operation
Presumed cause
Polarity of input does not
match.
Power supply for control
and input is abnormal.
Wiring or connection is
defective.
Input unit has failed.
Input device failure.
Polarity of output does not
match.
Power supply for output is
abnormal.
Wiring or connection is
defective.
Output unit has failed.
Output device failure.
Program etc. is defective.
-38-
Troubleshooting
If the polarity (PNP, NPN) of the input unit and the input
device are different, replace one of them to make the
combination match.
Check if the green PWR LED of the SI unit is ON. If the
LED is off, or the red LED is ON, supply 24 VDC ±10%
to the power supply for control and input.
Connect the wiring correctly between the digital input
device and the Digital input unit.
Replace the input unit with a normal one, and check the
operation.
Replace the input device with a normal one, and check
the operation. Or refer to the troubleshooting of the input
device used.
If the polarity (PNP, NPN) of the output unit and the
output device are different, replace one of them to make
the combination match.
Check if the green PWR(V) LED of the SI unit is ON. If
the LED is off, or the red LED is ON, supply 24 VDC
+10/-5% to the power supply for output.
Connect the wiring correctly between the digital output
device and the Digital output unit.
Replace the Output unit with a normal one, and check
the operation.
Replace the output device with a normal one, and check
the operation. Or refer to the troubleshooting of the
output device used.
Check if the ladder program of master, etc. is correct.
No.EX##-OMO0027