Rockwell Automation 1756-IH16ISOE ControlLogix Sequence of Events Module - Manual (Page 95)

Publication 1756-UM528A-EN-P - April 2004
Using The Sequence of Events Module in FIFO Mode 7-9
Using Enable CST Capture in FIFO Mode
Regardless of operating mode, Enable CST Capture causes the
Sequence of Events module to timestamp specific input transitions.
However, keep the following in mind when using this feature in
FIFO mode:
• The module is capable of timestamping an unlimited number
of transitions. However, at any one time the Sequence of
Events module can store the data for up to 160 events in its
on-board buffer. You must manage the buffer effectively (i.e.,
retrieve data) to make sure no events are missed or overwritten.
• The controller must retrieve data associated with each input
transition from the Sequence of Events module’s on-board
buffers. See Retrieving Data in FIFO Mode on page 7-10 to learn
how to manage the module’s on-board storage buffer.
• When the first transition is timestamped, the module sends the
data for that specific event, as well as the status of all the other
points on the module, to the controller and at every subsequent
RPI until the data is acknowledged.
• As subsequent events occur after the first, the module
timestamps the transition and records the data for that event in
its on-board buffer.
Use the Configuration tab in RSLogix 5000 to set Enable CST
Capture, as shown in the example below.
Click the Configuration tab.
• Click on the individual boxes
for each input point to enable
CST Capture for that point.
• Clear the individual boxes for
each input point to disable
CST Capture for that point.