Rockwell Automation 1732E-OB8M8SR EtherNet/IP Dual Port 8-Point SOE Input and Scheduled Output Modules UM - Manual (Page 83)

Rockwell Automation Publication 1732E-UM003B-EN-E - March 2014 73
Use the Sequence of Events Input and Scheduled Output Modules Chapter 10
The only exception to the process is that in Retrieval by Point, the current event is
not necessarily the data in the first slot of of the on-board buffer. Instead, the
current event is the first slot (up to 256 events per input) that contains data for a
transition timestamped at the specified input.
For example, if you are using Retrieval by Point to retrieve data for input 7 and
the first transition that occurs on input 7 is the 5th transition the module
timestamped, the current event is located in slot 5 of the module’s on-board
buffer.
Change Between Retrieval Methods
When using the Sequence of Events module in FIFO mode, you may determine
that you need to change retrieval methods. You can change retrieval methods, but
keep the following in mind before doing so:
• The change will NOT take effect until all events are acknowledged/cleared
from the module’s buffers.
• When you change retrieval methods dynamically, the ideal way is to reset
events in the module buffers (as described above) and immediately switch
FIFO retrieval modes. Make sure you do not need the data being cleared
from the module buffer prior to resetting events.
To change retrieval methods, change the O.RetrieveByPoint tag to the new
method.
• To use the standard retrieval by time method, O.RetrieveByPoint = 0
• To use the retrieval by point method, O.RetrieveByPoint = 1
Manage the Data
The module sends all of its input data to the controller the next RPI after an
input transition has been timestamped and at each subsequent RPI. You must
manage the data coming from the module.
The following occurs in the process of the managing data coming from the
module:
1. The module sends data to the controller.
2. The controller copies the relevant portions of the input data to separate
array.
3. At the user’s discretion, the controller clears latched timestamp data from
the module via the O.EventAck and O.NewData tags, preparing the
module to timestamp the next transition.
This process is described in the rest of this section.