Rockwell Automation 57C419 5V-24V DC Input Module - Manual (Page 29)

5Ć5
Step 3. Verify that the input circuit on the module 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.
Step 4. Verify that the module can be accessed.
Connect the programmer to the system and run the
ReSource Software. Use the I/O MONITOR function to
display register 1 and 2. Toggle the input device to
determine whether the bit is changing state. If it is not, the
input circuit on the module is malfunctioning.
Step 5. Verify that the hardware is working correctly.
Systematically swap out the input module, the processor
module(s), and the backplane. After each swap, if the
problem has not been corrected, replace the original item
before swapping out the next item.
5.3.2 Hardware Event TimeĆOut
Problem: All tasks in the chassis are stopped and error code 12"
appears on the faceplate of the Processor module. The interrupt has
either never occurred or is occurring at a slower frequency than the
value specified in the timeout" parameter in the event definition. Use
the following procedure to isolate the problem:
Step 1.
Verify that the timeout value is set correctly.
Check the value specified, if any, in the timeout"
parameter in the event definition. The unit is ticks. Each
tick is equal to 5.5 msec. The timeout value should be at
least 2 ticks greater than the interrupt frequency. It can
reasonably range up to 1.5 times the interrupt frequency.
Note that the `timeout' parameter is usually disabled since
the interrupt doesn't usually happen on a timed basis.
Step 2. Check for no interrupt.
Refer to section 5.3.1.
5.3.3 Hardware Event Count Limit Exceeded
Problem: All tasks in the chassis are stopped and error code 1B"
appears on the faceplate of the Processor module. A hardware
interrupt has occurred but no task is waiting. Use the following
procedure to isolate the problem:
Step 1.
Verify that the user application program is correct.
Verify that your interrupt response task contains either a
WAIT ON event" or CALL SCAN LOOP" statement that
will be executed. Check carefully to determine whether a
higher priority task is preventing the interrupt response
task from running.
Make sure that the ordering of your statements agrees
with the examples in section 4.4.
Step 2. Verify that the signal from the external device is clean.
Connect a scope to the input terminals and monitor the
pulse waveform from the external device. The waveform