Rockwell Automation 57C415 24V AC/DC Input Module - Manual (Page 18)

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 in the 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
in the remote I/O system nor in the remote rack, try
replacing the backplane.
5.2 Bus Error
Problem: A 31" or 51" through 58" appears on the processor
module's LED. This error message indicates that there was a bus
error when the system attempted to access the module. The possible
causes of this error are a missing module, a module in the wrong
slot, or a malfunctioning module. It is also possible that the user is
attempting to write to the wrong registers on the module. Refer to the
DCS 5000 Processor Module Instruction Manual (JĆ3635) orAutoMax
Processor Module Instruction Manual (JĆ3650) for more information.
Use the following procedure to isolate a bus error:
Step 1. Verify that the input module is in the correct slot and that
the I/O definitions are correct.
Refer to figure 3.2. Verify that the slot number being
referenced agrees with the slot number defined in the