Sequence of events recorder
Encyclopedia
A sequence of events recorder (SER) is an intelligent standalone microprocessor based system, which monitors external inputs and records the time and sequence of the changes. Sequence of events recorders usually have an external time source such as a GPS or radio clock
. When wired inputs change state the time and state of each change is recorded.
SERs enable rapid root cause analysis
after multiple events have occurred due to the secure recording of the sequence of events in the order of occurrence. SERs are therefore utilized as a diagnostic tool to minimize plant downtime. SERs are often interfaced with a SCADA
system, distributed control system
(DCS),or programmable logic controller
(PLC).
SER reports are used by electrical engineers to analyze large and small electrical system blackouts. After the Northeast blackout of 2003
, the North American Electric Reliability Corporation (NERC) specified that electrical system data should be time-tagged to the nearest millisecond
.
In 1984 The Tetragenics Company, a subsidiary of the Montana Power Company, introduced the first remote terminal unit (RTU) that time-tagged events to the nearest millisecond, and now there are also other RTUs with this capability. Digital protective relay
s and some PLCs now also include time-tagging to the nearest millisecond; SCADA systems that incorporate these devices provide SER functions without a dedicated SER device.
Radio clock
A radio clock or radio-controlled clock is a clock that is synchronized by a time code bit stream transmitted by a radio transmitter connected to a time standard such as an atomic clock...
. When wired inputs change state the time and state of each change is recorded.
SERs enable rapid root cause analysis
Root cause analysis
Root cause analysis is a class of problem solving methods aimed at identifying the root causes of problems or events.Root Cause Analysis is any structured approach to identifying the factors that resulted in the nature, the magnitude, the location, and the timing of the harmful outcomes of one...
after multiple events have occurred due to the secure recording of the sequence of events in the order of occurrence. SERs are therefore utilized as a diagnostic tool to minimize plant downtime. SERs are often interfaced with a SCADA
SCADA
SCADA generally refers to industrial control systems : computer systems that monitor and control industrial, infrastructure, or facility-based processes, as described below:...
system, distributed control system
Distributed control system
A distributed control system refers to a control system usually of a manufacturing system, process or any kind of dynamic system, in which the controller elements are not central in location but are distributed throughout the system with each component sub-system controlled by one or more...
(DCS),or programmable logic controller
Programmable logic controller
A programmable logic controller or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and machines...
(PLC).
SER reports are used by electrical engineers to analyze large and small electrical system blackouts. After the Northeast blackout of 2003
Northeast Blackout of 2003
The Northeast blackout of 2003 was a widespread power outage that occurred throughout parts of the Northeastern and Midwestern United States and Ontario, Canada on Thursday, August 14, 2003, just before 4:10 p.m....
, the North American Electric Reliability Corporation (NERC) specified that electrical system data should be time-tagged to the nearest millisecond
Millisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
.
In 1984 The Tetragenics Company, a subsidiary of the Montana Power Company, introduced the first remote terminal unit (RTU) that time-tagged events to the nearest millisecond, and now there are also other RTUs with this capability. Digital protective relay
Digital protective relay
In electrical engineering of power systems, a digital protective relay uses a microcontroller with software-based protection algorithms for the detection of electrical faults...
s and some PLCs now also include time-tagging to the nearest millisecond; SCADA systems that incorporate these devices provide SER functions without a dedicated SER device.