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Chapter 10
Use the Sequence of Events Input and Scheduled Output Modules
72
Sort the Data
If you need to determine the order of events that occurred in a cascade, you
must use a Sort routine to determine the order of events. Rockwell Automation
offers a sample sort routine that you can use to determine the order of events
in an event cascade.
Visit the Rockwell Automation Sample Code Library at
https://www.rockwellautomation.com/en-us/support/product/product-
downloads/application-code-library/sample-code.html.
Clear All Data From the Module Buffer At Once
If necessary, you can reset the events in the module, in effect clearing all data
from previously timestamped transitions. In other words, when all data is
cleared from the module buffers, all of the module input tags return to 0.
To reset events in the module buffer, transition the O.ResetEvents tag to 1 as
described below:
•
If the bit = 0, change the bit to 1.
•
If the bit = 1, change the bit to 0, wait for at least one RPI, and change the
bit to 1.
Once the data is cleared, the module begins timestamping input transitions
again and storing them in its on-board buffer.
Propagate a Signal From Input Pin to Ethernet
The module receives a signal at its input pin and processes it internally before
sending the input and timestamp data to the controller at the Requested
Packet Interval (RPI) via Ethernet.
When you operate the module, you must account for signal propagation delays
that exist during internal processing. Some of these delays are inherent to the
module and others are controlled by temperature and input voltage.
During processing, the following delays exist:
•
Hardware delay – The time it takes an input signal to propagate from the
module input pin to its microprocessor. This time varies according to
input transition type (OFF to ON/ON to OFF), input voltage and
temperature.
•
Firmware delay time – The time it takes the module to acquire a
timestamp once its microprocessor receives the input signal.
•
Input filter delay – user-configurable number from 0...16 ms. The input
filter does not affect when the timestamp is acquired. It acquires the
"firmware delay time" after the input changes state at the module
microprocessor. The input filter simply delays the amount of time the
input must be in a certain state before input is considered valid and the
timestamp data will be sent to the controller.
•
RPI – Once the timestamp is acquired by the microprocessor and the
input is filtered, the input and timestamp data is sent to the controller at
the next RPI.
Rockwell Automation Publication 1732E-UM003D-EN-E - November 2021
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