Different Types of Alarms in distributed control systems (DCS) or Emergency Shutdown systems (ESD) are as foolows.
Types of Alarms
Alarm: Equipment status alarm. Pump is on or off, or motor is running or stopped.
Alarm: Abnormal measurement alarm. Measurement is outside of specified limits.
Alarm: An alarm switch without its own sensor. When it is not necessary to know the actual value of the process variable, only whether it is above (or below) a specified limit.
Alarm: An alarm switch with its own sensor. This serves as a backup in case the regular sensor fails.
Alarm: Automatic Shutdown or Startup System.