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Chapter 4 Troubleshooting
4-3
Continued
Is the LED of SWITCH1, 2 on?
No
Check the voltage of Switch 1, 2
by a tester
Ye
s
Is the measurement normal?
Separate the external wiring
and check the input status by
forcible input.
Is the measurement normal?
Check the status of input
devices(switch 1,2).
Replace the input
module.
Measure the terminal voltage of
Switch 1,2 by a tester
Is the measurement normal?
Is the tightness of
a terminal good?
Is the input wiring correct?
Is wiring correct?
Tighten the terminal
screw.
Replace the terminal
strip connector.
Replace the input
module.
Check it from the first step
Is the contact of terminal strip
connector correct?
Yes
No
No
Ye
s
No
Ye
s
Ye
s
No
Yes
No
No
Yes