Rockwell Automation 1732E-OB8M8SR EtherNet/IP Dual Port 8-Point SOE Input and Scheduled Output Modules UM - Manual (Page 65)

Rockwell Automation Publication 1732E-UM003B-EN-E - March 2014 55
Specific Features of the 1732E-IB8M8SOER Sequence of Events Input Module Chapter 8
Software Configurable
Input Filters To account for hard contact “bounce”, you can configure ON to OFF and OFF to
ON input filter times in RSLogix 5000 software for your module. These filters
define how long an input transition must remain in the new state before the
module considers the transition valid.
When an input transition occurs, the module timestamps the transition on the
initial edge of the transition and stores data for the transition on-board; the
module then scans the input where the transition occurred every millisecond for
the length of the filter time setting to verify that the input remains in the new
state (remained OFF or ON).
• If the input remains in the new state for a time period equal to the filter
time setting, the module sends data for the transition to the controller.
When an input transition is detected, the module counts the number of
1 ms intervals the input is in the new state until the count reaches the filter
value.
• If the input changes state again (returns to the original state) before the
length of time of the filter setting has elapsed, the module starts
decrementing the number of 1 ms intervals counted until it reaches zero.
At this point the module stops filtering the input and discards the
timestamp. During this continued scan period, one of the following events
occurs:
– At some point while still filtering the input, the input returns to the
transitioned state and remains there until the module counts the
number of 1 ms intervals equal to the filter setting. In this case, the
module sends data from the transition to the controller.
– The input does not remain in the transitioned state for a time period
equal to the filter setting and the 1 ms counter decrements to zero. In
this case, the module does not consider the original transition valid and
drops the timestamp.
The following example illustrates how the module’s input filters operate.
In the example, a module:
• is Timestamp Capture-enabled for all of its points
• uses a 2 ms input filter setting for OFF to ON transitions
Three possible scenarios can result after an input transitioning from OFF to ON
in the given circumstances.
IMPORTANT Input filters are applied to all inputs on the module. You
cannot apply input filters to individual inputs on the
module.