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Alarm Annunciator Overview

Omniflex is a leading supplier of alarm annunciators and systems, and has been designing and manufacturing alarm systems for over 55 years.

Alarms are vital tools in the management of safety on industrial plants today, and the alarm annunciator is a key component of these safety systems.

Alarm annunciators have a long history in most sectors of industry and remain a vital tool in keeping processes safe.


View/download our full Alarm Annunciator Sector Overview pdf document

What is an Alarm?

Within industrial applications an alarm can be defined as an “indication requiring an immediate response by the operator”.

Such indication normally reflects an abnormal condition within the plant or process.

Responding to these alarms appropriately and timeously is vital to ensure that the plant or process remains safe.

What is an Alarm Annunciator?

Alarm annunciators are devices which accept inputs from field sensors (typically hard-wired switches in the plant, arranged to operate when a process condition enters an abnormal state, such as high temperature, low pressure, loss of cooling water flow, or many others). and provide visual indication, such that each illuminated light on the annunciator can be immediately and uniquely associated with a specific process condition.

Defined flashing of the alarm windows gives the operator quick and simple indication of the state of the alarm.

Why are Alarm Annunciators separate devices?

The purpose of an alarm annunciator is to provide a reliable indication to the operator of the state of critical aspects of the process under any failure condition.

Alarm Annunciators need to be relied upon to always alert the operator when any abnormal condition occurs that can affect safety, including the failure of the control system. The alarm annunciator is considered an additional and independent "layer of protection", and is vital when considering the overall safety of the plant.

SIL Rating of Alarm Annunciators

Because of their critical application in protecting people and assets, alarm annunciators need to be demonstrated to be reliable under any condition.

When alarms are programmed into PLC or DCS software, there is always the undefinable risk that an error in the software programming will mask the alarm when it is most needed.

For this reason, alarm annunciators undergo rigorous qualification during the design phase to ensure that their performance can be assured to a high enough degree of certainly.

More recently, the IEC61508 standard has become the norm by which most safety systems are rated. According to this standard, safety loops must meet  a defined "Safety Integrity Level" which required definitive calculation of the reliability of every component in the safety loop including the alarm annuncaitor and the operator.

The Omniflex Omni16 family of alarm annunciators have undergone independent scrutiny to ensure that they comply with the highest required level of safety for alarm indication systems. 

Omni16C Nuclear Industry Approved

Surely the industry with the highest demand on safety is the nuclear industry. Because of this heightened awareness for safety, the Nuclear Industry in the United Kingdom has added an additional requirement for intelligent devices.  All intelligent devices deployed on nuclear plants in the UK must undergo an additional rigorous software and hardware assessment process known as the EMPHASIS program.

The Omni16C from Omniflex is the only intelligent alarm annunciator to have met all of the requirements of this program including serial communications.


When safety is your concern be sure to specify the Omni16C SIL rated Alarm Annunciator for complete peace of mind.

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Alarm System Obsolescence

One of the requirements in the assessment of safety systems is assessment of the complete lifecycle fo the safety system.

Many alarm systems are still in operation performing critical safety roles that are now beyond the end of their design life. In many cases, the manufacturers of these systems are no longer in business, and as the equipment starts to fail, support and maintenance becomes a real issue.

Omniflex understands the criticality of these obsolete alarm systems to the safety and performance of the plant, and works with the operator to upgrade these systems to acceptable safety standards with minimum downtime.

Omniflex alarm specialists will work with your plant engineers to tailor a unique solution for your exact needs. Contact Omniflex for a free assessment.

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