Rockwell Automation 1756-XXXX ControlLogix Digital I/O Modules - Manual (Page 91)

Rockwell Automation Publication 1756-UM058G-EN-P - November 2012 91
Fast Module Features Chapter 5
Figure 9 - Valid Transition with No Bounce
Figure 10 - Transition Valid with Bounce
Figure 11 - Invalid Transition
0 1 2 3 4 5 6 7 8
Input turns On, and a
timestamp is recorded.
Time in milliseconds
Input remains On for at least 2 ms. The transition is
considered valid, and the timestamp is sent to the controller.
0 1 2 3 4 5 6 7 8
Time in milliseconds
Input turns On and remains On for at least 2 ms in the
20 ms time period that is 10x the input filter time.
The module sends the timestamp recorded at the
original transition point (time 0) to the controller.
Input turns Off before 2 ms elapses.
Input turns On, and a
timestamp is recorded.
0 1 2 3 4 17 18 19 20
Time in milliseconds
Input turns Off before 2 ms elapses.
The input never remains
On for at least 2 ms.
After the 20 ms time period that is 10x the input filter
time, the module drops the data recorded at the
original transition. If an RPI occurs during this time,
the module sends the controller its current valid input
data. The data that is sent does not include data from
the transition because the input transition has not
cleared the filter and been recognized as a valid input.
Input turns On, and a
timestamp is recorded.
The next time the input turns On, the module
records the transition as timestamp 21.6 once
the input passes the filter time.
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