I have previously written about alarms and following on from yesterday's post I want to write about stale alarms.
These are alarms that initially come in, but for some reason the operator cannot remove them. They are usually classed as stale if they have been on the alarm page continuously …
I have previously written about nuisance alarms particularly during shutdowns, but today I want to cover the fundamental questions of what an alarm is and what it is not.
The definition of an alarm is:
Alarm: An audible and/or visible means of indicating to the operator an equipment malfunction …
Earlier today I commissioned a project I have been working on for the last year, ESD Dynamic Alarm Suppression.
When the Emergency Shutdown (ESD) System is activated, shutdown valves will close and pumps will stop. This normally causes a significant flood of extra alarms as the normal control system warns …
