Rockwell Automation 1732E-OB8M8SR EtherNet/IP Dual Port 8-Point SOE Input and Scheduled Output Modules UM - Manual (Page 82)

72 Rockwell Automation Publication 1732E-UM003B-EN-E - March 2014
Chapter 10 Use the Sequence of Events Input and Scheduled Output Modules
This process continues as long as the Sequence of Events module timestamps
input transitions and the controller continues to retrieve the data for each
transition.
Retrieval by Point
Retrieval by Point is similar to Standard Retrieval by time except that with this
method, the controller only retrieves timestamp data for input transitions that
occurred on a specific point.
The Sequence of Events module still timestamps input transitions for any events
that occur on Enable Timetamp Capture-enabled inputs. The module stores up
to 256 events per input.
Additional Module Settings Required with Retrieval by Point Method
By default, the Sequence of Events module operates as if the controller will use
Standard Retrieval to retrieve data. To use the Retrieval by Point method, you
must change the following two tags in the module’s output word:
• O.RetrieveByPoint = 1 (default value is 0)
• O.PointtoRetrieve = input point for which you want the controller to
retrieve data – for example, if you want to retrieve the data for input 8, you
must change this tag to 8.
Retrieval Process Similar to Standard Retrieval
After you make the output tag changes listed above, the controller retrieves the
data for each transition on the specified input in the order in which the
transitions occur.
IMPORTANT The module stores up to 256 events per input. Each input's buffer is
independent of the others.
You must manage the module buffer effectively to make sure that the
module timestamps all transitions on a specific input.
Consider the following example:
You are using Retrieve by Point to retrieve timestamp data from input 4,
and 10 of the first 34 input transitions that the Sequence of Events
module timestamps occur on input 4.
If Latch Timestamp is enabled for the module and you fail to clear any
of the timestamp data for input 4 before the input transitions again, the
Sequence of Events module will not timestamp the next transition for
input 4, even though there are 126 slots still available in the module’s
on-board buffer.