Alarm - AbsoluteAstronomy.com

An alarm device or system of alarm devices gives an audible or visual alarm signal about a problem or condition.

Alarm devices include:

burglar alarm
Burglar alarm
Burglar , alarms are systems designed to detect unauthorized entry into a building or area. They consist of an array of sensors, a control panel and alerting system, and interconnections...

s, designed to warn of burglaries; this is often a silent alarm: the police or guards are warned without indication to the burglar, which increases the chances of catching him or her.
alarm clock
Alarm clock
An alarm clock is a clock that is designed to make a loud sound at a specific time. The primary use of these clocks is to awaken people from their night's sleep or short naps; they are sometimes used for other reminders as well. To stop the sound, a button or handle on the clock is pressed; but...

s can produce an alarm at a given time
distributed control manufacturing 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...

s or DCSs, found in nuclear power plants
Nuclear reactor
A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...

, refineries
Refinery
A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value.-Types of refineries:Different types of refineries are as follows:...

and chemical facilities also generate alarms to direct the operator's attention to an important event that he or she needs to address.
alarms in an operation and maintenance (O&M) monitoring system, which informs the bad working state of (a particular part of) the system under monitoring.
- first-out alarm
  First-out alarm
  A first-out alarm is an alarm that indicates in some manner that it was the first of a series. This is necessary in circumstances such as an automatic trip or shutdown of equipment, where many alarms will annunciate as a result of a shutdown. The first-out alarm will clearly identify the root...
safety alarms, which go off if a dangerous condition occurs.