Process control Annunciator panel

alarm annunciator used process controls



alarm annunciators being used in electricity distribution substations



example of alarm annunciator used in variety of different plants.

annunciator panels relatively costly install in plant because had dedicated wiring alarm initiating devices in process plant. since incandescent lamps used, lamp test button provided allow detection of failed lamps. modern electronic distributed control systems require less wiring since process signals can monitored within control system, , engraved windows replaced alphanumeric displays on computer monitor.

behavior of alarm systems, , colors used indicate alarms, standardized. standards such isa 18.1 or en 60073 simplify purchase of systems , training of operators giving standard alarm sequences.

obsolescence , revival

the introduction of computer monitor based control systems during 1980s , 1990s saw wholesale absorption of alarm window displays on computer screen. created down-turn in sales of conventional alarm annunciator systems , many of companies manufacturing these alarm annunciator products either sold off or went out of business. has left today major obsolescence support problem customers still using these alarm annunciator systems part of safety systems.

over last 5 years alarm annunciator has seen resurgence in popularity use in iec61508 sil 1 , (safety health , environmental) alarm monitoring applications. modern trend identify critical alarms , return them computer screen discrete alarm windows. being done 2 reasons. firstly, alarm annunciators offer pattern recognition operators in form of led alarm fascias instead of providing exhaustive list of alarms , events operators have scroll through , in instances alarms can overlooked. secondly, analysis of plant failure modes leading separation of critical alarm monitoring , process control systems safety reasons.

discrete annunciators vs scada alarm systems

scada systems formerly considered preferred alternative discrete annunciators. software-based solution, endless ability analyze, present , process alarms, has potential replacing discrete alarms switches altogether.

however, software carries own reliability risks. reliance on software program trigger alarm assumes analog signal, programmer s logic code , hmi, plc or pc running programs, , interaction between of above, entirely trustworthy. exacerbated changing computer hardware & firmware platforms , need modify existing software. alternatively new annunciator panels utilizing long lasting , bright leds reduce cost , maintenance of panels. these new versions of traditional system still preferred on computer based systems in critical plants nuclear power generation, oil , gas.

in addition above, latest annunciator designs feature clever electronics give them high immunity noise, , can therefore reduce amount of false alarms due noise.