Rockwell Automation 1756-IH16ISOE ControlLogix Sequence of Events Module - Manual (Page 76)

Publication 1756-UM528A-EN-P - April 2004
6-4 Using The Sequence of Events Module in CST Per Point Mode
What Are The Typical
Applications Where CST
Per Point Mode is Used? CST Per Point mode is typically used in applications that need to
determine relative first fault detection after an event cascade occurs.
The Sequence of Events module can provide unique timestamps for
separate input transitions as long as they occur 25
µs apart; you can
sort the data resulting from an event cascade to determine where the
first input transition occurred in the cascade.
You can also use the 1756HP-GPS module to give the stored CST
timestamps a real-time reference. For more information on how to
integrate the 1756HP-GPS module into your ControlLogix Sequence of
Events system, see Appendix B.
The following are example typical applications for CST Per
Point mode:
• Substation automation
• Load-shedding/energy management
• Emergency shutdown systems
Configuring the Module for
CST Per Point Mode You configure the same general set of configurable features
(described in Chapter 5) whether you are using the Sequence of
Events module in CST Per Point mode or FIFO mode. However, for
some features, the module behavior as dictated by the feature,
varies according to operational mode. For example, Latch CST
impacts the Sequence of Events module behavior slightly
differently in CST Per Point mode than in FIFO mode.
You should be aware of the impact the following configurable
features have on module behavior in CST Per Point mode:
• Communications Format
• Latch CST
• Enable CST Capture
• Universal Coordinated Time (UCT)