Rockwell Automation 57C400-1 115V AC/DC Input Module - Manual (Page 20)

5Ć2
If operation is intermittent, verify that the program reading
the module is executing fast enough to catch all of the
input changes.
Step 5. Verify that the hardware is working correctly.
Toggle the input device. Verify that the LED associated
with the particular bit is also toggling. If it is not, the input
circuit on the module is malfunctioning.
Verify the hardware functionality by systematically
swapping out modules. After each swap, if the problem is
not corrected, replace the original item before swapping
out the next item.
D To test local I/O, first replace the input module. Next,
replace the processor module(s). If the problem
persists, take all of the modules out of the backplane
except one processor module and the input module. If
the problem is now corrected, one of the other
modules in the rack is malfunctioning. Reconnect the
other modules one at a time until the problem
reappears. If none of these tests reveals the problem,
replace the backplane.
D To test remote I/O, first verify that the remote I/O
system is communicating with the drop that contains
the input module being tested. Next, determine
whether the input module is the only module that is not
working. If more than one module is not working
correctly, the problem most likely lies inthe remote I/O
system. If the problem does not lie in the system, it
probably involves the remote rack.
D To test the remote rack, first replace the input module.
Next, replace the slave remote I/O module. If the
problem persists, take all of the modules out of the
remote backplane except the slave remote I/O module
and the input module. If the problem is now corrected,
one of the other modules in the rack is malfunctioning.
Reconnect the other modules one at a time until the
problem reappears. If the problem proves to be neither
inthe remote I/O system nor inthe remote rack, try
replacing the backplane.