In recent years there has been increasing focus on the importance of a properly designed
When DCS and SCADA systems were first introduced it was easy (and inexpensive) to
simply add more and more alarms to the system without considering the overall effect.
This was frequently done on the basis of "if in doubt, generate an alarm".
This led to situations
where there are simply too many alarms - often more of a nuisance than providing the operator
with clear advice concerning the state of the process.
More recently, publication of EEMUA 191 and initiatives of industry groups such as the ASM
Consortium have led, quite rightly, to much-needed reassessment of alarm systems, particularly
from a viewpoint of alarm rates. The number of alarms occurring in a 10 minute interval is now
a common benchmark for assessing alarm system performance.