Specifications

10–27 Troubleshooting
Publication 1747-6.2
Troubleshooting Your Input Modules
If your Input
Circuit LED is
And Your Input
Device is
And Probable Cause Recommended Action
Your input device will not turn
off.
Device is shorted or
damaged.
Verify device operation. Replace device.
On/Closed/Activated
Your program operates as
Input circuit is
damaged.
Verify proper wiring. Try other input
circuit. Replace module.
You
r pr
o
gr
a
m
o
per
at
es
a
s
though it is off.
Input is forced off in
program.
Check the FORCED I/O or FORCE LED
on processor and remove forces.
On
n acti at
Your program operates as
t ou it i on an o t in ut
Input device Off-state
leakage current
exceeds input circuit
specification.
Check device and input circuit
specifications. Use load resistor to
bleed-off current.
Off/Open/Deactivated though it is on and/or the input
circuit will not turn off.
Input device is shorted
or damaged.
Verify device operation. Replace device.
Input circuit is
damaged.
Verify proper wiring. Try other input
circuit. Replace module.
Input circuit is
incompatible.
Check specification and sink/source
compatibility (if DC input).
Low voltage across the
input.
Check the voltage across input circuit
and check source voltage.
On/Closed/Activated
Your program operates as
though it is off and/or the input
ci cuit ill not tu n on.
Incorrect wiring or an
open circuit.
Check wiring and COMmon
connections.
circuit will not turn on.
Input signal turn on
time too fast for input
circuit.
Check timing specifications.
Off
Input circuit is
damaged.
Verify proper wiring. Try other input
circuit. Replace module.
Your input device will not turn
on.
Input device is shorted
or damaged.
Verify operation. Replace device.
Off/Open/Deactivated
Your program operates as
though it is on.
Input is forced on in
program.
Check processor FORCED I/O or
FORCE LED and remove forces. Verify
proper wiring. Try other input circuit.
Replace module.
t
h
ou
gh
it i
s
on.
Input circuit is
damaged.
Verify proper wiring. Try other input
circuit. Replace module.