Rockwell Automation 57C419 5V-24V DC Input Module - Manual (Page 28)

5Ć4
reappears. If the problem proves to be neither in the
remote I/O system nor in the remote rack, try replacing the
backplane.
5.3 Interrupt Problems
Problem: No interrupts at all, or too many (unexpected) interrupts,
signified by error codes being displayed on the faceplate of the
Processor module. Go through the following steps first before going
on the the more specific troubleshooting steps:
Step 1.
Verify that the input module is in the correct slot.
Refer to figure 3.4.
Step 2. Verify that the I/O definitions are correct.
Verfiy that the configuration task contains the proper
interrupt control definitions. Refer to the example in
section 4.6.
Step 3. Verify that the user application program is correct.
Verify that the application program that uses the symbolic
names defined in the configuration task has defined those
names as COMMON.
Compare your interrupt task with the examples given in
sections 4.4.1 and 4.4.2. Make sure that the actions shown
in the examples are performed in the same order in your
task.
5.3.1 No Interrupts
Problem: The task does not execute but no error codes are displayed
on the Processor module faceplate. If interrupts are never received
and the timeout" parameter in the event definition was disabled, the
task will never execute. Use the following procedure to isolate the
problem:
Step 1.
Verify that the user application program is correct.
Verify that your interrupt response task is checking the
proper latch status bit to determine which bit caused the
interrupt. Confirm that when an interrupt has been located,
the latch reset bit is being reset.
Compare your interrupt task with the examples given in
sections 4.4.1 and 4.4.2. Make sure that the actions shown
in the examples are performed in the same order in your
task.
Step 2. Verify that the input is wired to the correct device.
Confirm that all connections at the terminal strip are tight.
Connect a voltmeter to the proper points on the terminal
strip and toggle the device. The voltĆ meter should
alternate between 0 and the DĆC power supply voltage
(5Ć24 volts). If this does not happen, there is a problem
with either the external device, the DĆC power supply, or
the wiring to the terminal strip.
If the device generates a pulse output, use a scope and
verify that the pulse width is at least .7 msec.