Rockwell Automation 1732E-OB8M8SR EtherNet/IP Dual Port 8-Point SOE Input and Scheduled Output Modules UM - Manual (Page 81)

Rockwell Automation Publication 1732E-UM003B-EN-E - March 2014 71
Use the Sequence of Events Input and Scheduled Output Modules Chapter 10
The following occurs in the process of the managing data coming from the
Sequence of Events module in CIPSync/PTP Per Point mode:
1. The controller retrieves current event data from the Sequence of Events
module in one of two retrieval methods.
2. The controller copies the relevant portions of the current event data to a
separate array.
3. At the user’s discretion, controller clears current data from the Sequence of
Events module by copying the current event number (I.EventNumber) to
the O.EventAck tag, preparing the module send data from the next current
event.
This process is described in the rest of this section.
Retrieve Data in FIFO Mode
In FIFO Mode, the Sequence of Events module automatically sends the
controller the data from the first timestamped transition in its buffer. The
controller must retrieve the data for the remaining timestamped transitions in the
Sequence of Events module’s buffers.
The controller can retrieve data in one of the following ways:
• Standard Retrieval – By default, the module uses this retrieval method
which returns events in order of occurrence.
• Retrieval by Point
Standard Retrieval
In Standard Retrieval, the controller retrieves the data for each event in the order
in which the events occurred. This retrieval method includes the following:
1. At each RPI, the Sequence of Events produces the current event in its on-
board buffer.
2. The controller copies relevant input data from the current event to a
separate data structure for later use.
3. The controller clears the current event from the Sequence of Events
module’s on-board buffer by acknowledging the data via the module’s
output word.
4. When the current event is cleared, the next event in the module’s on-board
buffer becomes the new current event. If no other events are present, the
event data will be 0.
5. The Sequence of Events module produces the new current event as
described in step 1.