Gestão de Alarmes

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CHAPTER 1

Meet Alarm Management

If you need a new machine and don’t buy it, you pay for it anyway but never get to

use it.

—Henry Ford

An alarm is an announcement to the operator initiated by a process variable (or

measurement) passing a defi ned limit as it approaches an undesirable or unsafe

value. The announcement includes audible sounds, visual indications (e.g., fl ashing

lights and text, background or text color changes, and other graphic or pictorial

changes), and messages. The announced problem requires operator action. An alarm is a

construction by which an aspect of manufacturing operation is identifi ed and confi gured

in a binary way to be either “in alarm” or “cleared” (i.e., not in alarm). The condition

of in alarm is passed to an operator via intrusive sounds and notices placed on video display

units or other devices to gain attention. The operator can manage these sounds and

notices only via specifi c “silence the alarm” or “acknowledge the alarm” actions using

the existing, planned infrastructure of the alarm platform. Usually, this alarm platform is

an integral part of the process control system (PCS) infrastructure.

The PCS alarm system is a vital and productive tool for managing industrial process

control plants. Through several unique cooperative endeavors, industry has identifi ed a

best practice for alarm system design. This design utilizes confi guration changes, alarm

reprioritization and balancing, alarm reductions, graphics modifi cations, online fi ltering,

and decision support aids. Alarms perform the vital function of operational integrity

monitoring. Properly designed alarms will notify the operator of abnormal situations

with enough time to successfully manage them.