Alarm setpoints, deadbands, annunciation, rationalization, flooding, shelving, and on/off delays. 90 terms in this topic - each defined in plain English on its own page.
Alarm setpoints, deadbands, annunciation, rationalization, flooding, shelving, and on/off delays.
Benchmark rates for standing, average, and peak alarms that keep one operator able to keep up.
Read → GlossaryThe operator action of ack'ing an alarm, plus the active/normal and acked/unacked state model.
Read → GlossaryChoosing Alert and Danger setpoints from ISO zones and baseline, with voting and delays to avoid nuisance trips.
Read → GlossaryThe persistent strip on every screen that surfaces the top unacknowledged alarms so none are missed.
Read → GlossaryVisual alarm device that flashes for alarms in high noise, rated in candela and colour-coded by alarm type, driven by F&G logic.
Read → GlossaryIndependent on-delay and off-delay timers: the on-delay ignores transients, the off-delay holds through brief recoveries to stop flicker.
Read → GlossaryThe gap between an alarm's trip and reset points that stops chatter, sized to the signal's noise.
Read → GlossaryTiered routing of an unacknowledged alarm to on-call staff by SMS, email, and voice for unmanned sites.
Read → GlossaryA burst of alarms that overwhelms an operator - ISA-18.2's 10-in-10-minutes threshold, its causes, and how to prevent it.
Read → GlossaryThe ten-in-ten-minute threshold that defines a flood, distinct from average rate, reported as time in flood.
Read → GlossaryHow one trip cascades through interlocks or comms loss alarms every point, and how first-out and sequence-of-events reconstruction finds the root.
Read → GlossaryFirst-out logic, cause-based suppression, and grouping that cut the flood an operator sees during a trip.
Read → GlossaryConsolidating related points into one logical alarm by unit, cause, or geography so an event annunciates once.
Read → GlossaryAverage and peak alarm rate, time in flood, standing alarms, and the ISA-18.2 and EEMUA target values.
Read → GlossaryThe approved, logged workflow for changing any alarm attribute that keeps rationalization from decaying.
Read → GlossaryTime delays that stop chattering and transient alarms by requiring a condition to persist first.
Read → GlossaryTimers that make an alarm wait before annunciating or clearing, filtering out momentary transients.
Read → GlossaryThe minimum duration a condition must stay true before the alarm annunciates, filtering momentary spikes that need no action.
Read → GlossaryThe governing rulebook defining priority, HMI, and rationalization rules as ISA-18.2 lifecycle stage one.
Read → GlossaryThe ranking set by consequence and response time that tells operators which alarm to handle first.
Read → GlossaryReserving specific colors and cues for alarm priorities so operators read severity at a glance, unused by normal graphics.
Read → GlossaryThe documented ABC framework that assigns every alarm a consistent priority from consequence and response time.
Read → GlossaryThe ISA-18.2 review that decides which alarms are justified, what they mean, and how urgent each one really is.
Read → GlossaryThe documented cause, consequence, and corrective action an operator follows, often shown as HMI help text.
Read → GlossaryThe alarm warns for operator action; the trip acts automatically. Learn to place the alarm inside the trip and size the margin.
Read → GlossaryThe tiered LL, L, H, HH limits and how each level maps to escalating operator response.
Read → GlossaryThe controlled, time-limited way an operator silences a known nuisance alarm - with automatic re-activation so nothing stays hidden.
Read → GlossaryAudible notification device rated in dB(A) above ambient noise, with selectable tones and coverage spacing, wired to a supervised circuit.
Read → GlossaryThe live list of active alarms operators sort, prioritize, and acknowledge.
Read → GlossaryAutomatic, logic-driven hiding of alarms irrelevant to the current plant state, distinct from shelving.
Read → GlossaryThe periodic ISA-18.2 review that benchmarks alarm performance against KPI targets and drives improvement.
Read → GlossaryThe ISA-18.1 style states a point moves through: flash, horn, acknowledge-to-steady, ringback, and reset.
Read → GlossaryWhy a handful of tags drive most alarm load, and the top-ten ranking and workflow to resolve them.
Read → GlossaryAn alarm that trips when a value leaves a window bounded by both an upper and lower limit, for variables bad in either direction.
Read → GlossaryAn alarm triggered by an expression over several tags, like high flow with low pressure, only as good as its worst input.
Read → GlossaryThe ordered chain of contacts a monitoring system dials or texts until someone acknowledges an alarm.
Read → GlossaryThe handshake that preloads a primary to the secondary's setpoint so closing a cascade causes no bump.
Read → GlossaryAn alarm that rapidly cycles active and clear near its setpoint, cured by deadband and delays.
Read → GlossaryOne controls when a historian stores a sample, the other prevents alarm chatter, both tuned in percent of span.
Read → GlossaryA known downstream effect of another alarm, suppressed via defined cause-consequence pairs so operators see the root cause.
Read → GlossaryThe range where a change produces no action, why it stops valve hunting and nuisance alarms, and how it is used in SCADA.
Read → GlossaryDeviation trips on error from a moving setpoint; absolute trips on a fixed value. A guide to which to use and how each misleads.
Read → GlossaryEvaluating and latching alarm conditions on the gateway so trips survive a loss of connectivity.
Read → GlossaryThe UK alarm management guideline that set benchmark alarm rates like one alarm per ten minutes.
Read → GlossaryAn alarm sent to a mailbox by SMTP, fine for low-priority alerts but unreliable for time-critical ones.
Read → GlossaryThe grid of severity and time-unacknowledged that maps who is contacted at each tier, designed so critical alarms never dead-end.
Read → GlossaryThe logic that flags which alarm tripped first in a shutdown cascade, so operators find the root cause instead of the symptoms.
Read → GlossaryThe alarm panel whose first-out logic flags the initiating trip alarm.
Read → GlossaryThe first-cause capture that flags which single input actually initiated a cascading trip, tied to sequence of events.
Read → GlossaryA strategy that takes no action while error stays inside a band around setpoint, cutting valve travel on surge tanks and noisy loops.
Read → GlossaryThe two-stage %LEL scheme: a low alarm near 20% LEL and a high alarm near 60% LEL, both below the explosive limit.
Read → GlossarySite-wide emergency signal telling everyone to stop and respond, sitting above gas and prepare-to-abandon in the tone hierarchy.
Read → GlossaryWatching the gap between operating temperature and the calculated dew point at line pressure to warn of liquid dropout.
Read → GlossaryThe critical high-high alarm that warns of an imminent sewer overflow and triggers an operator callout.
Read → GlossaryThe overfill alarm that uses its own sensor, wiring, and logic separate from the tank gauging transmitter.
Read → GlossaryThe alarm management standard defining a lifecycle from philosophy through audit, aligned with IEC 62682.
Read → GlossaryAn alarm that stays annunciated after the condition clears until reset - latching vs non-latching for trips.
Read → GlossaryThe D&R record of every alarm's setpoint, cause, consequence, and required operator action.
Read → GlossaryAutomatically hides alarms expected in the current mode, like startup or shutdown, so operators avoid nuisance floods.
Read → GlossaryThe National Fire Alarm and Signaling Code: initiating devices, notification, integrity monitoring, and F&G-to-ESD interface.
Read → GlossaryHow gain that varies with error size and an error deadband cut valve wear and cycling on noisy loops.
Read → GlossarySuppressing repeat notifications for the same recurring condition so one event does not send dozens of messages.
Read → GlossaryA periodic summary that batches low-priority alarms instead of sending one message per event.
Read → GlossaryThe chattering, fleeting, and stale alarms that clutter a screen without any real action - and the deadband and delay fixes for them.
Read → GlossaryThe timer that holds an output ON for a set time after its input turns OFF, for run-on and cooldown logic.
Read → GlossaryA discrete alarm that fires when a device leaves its expected state, like a running pump that stopped or a breaker that opened.
Read → GlossaryThe most-used PLC timer - preset, accumulator, and done bit - that delays an action after an input turns on.
Read → GlossaryThe ISA-18.2 state for an alarm intentionally removed for maintenance or decommissioning, requiring authorization and tracking.
Read → GlossaryA combined voice-and-tone system that alerts an entire facility, engineered for intelligibility and driven by F&G and ESD.
Read → GlossaryA low-priority advisory that fires before the main alarm, giving operators lead time to correct a trend before it becomes an excursion.
Read → GlossaryPlacing the vent set pressure and vacuum in the roof hierarchy above blanketing and below the tank design limits.
Read → GlossaryThe fillage or load threshold on the dynamometer card that tells a pump-off controller to shut a well in.
Read → GlossaryRe-annunciation of an acknowledged group when a new or higher sub-condition arrives, so operators are re-alerted.
Read → GlossaryAcknowledging an alarm off-site by text reply, push tap, or voice keypress, with audit and security implications.
Read → GlossaryHow bad-actor frequency analysis isolates a repeating alarm's cause and why fixing repeaters cuts alarm load fastest.
Read → GlossaryThe threshold that decides when to transmit a new value versus the deadband used inside a controller.
Read → GlossaryThe transition of an alarm from active back to normal, confirming a condition cleared as a tracked event.
Read → GlossaryThe target value a control loop drives toward, how it differs from the process variable, and how remote setpoints work in SCADA.
Read → GlossaryHorizontal reference lines for setpoints and limits that show margin to a limit at a glance on a trend.
Read → GlossaryHow beta and gamma factors decouple setpoint tracking from disturbance rejection and tame proportional kick.
Read → GlossaryA standing report of every suppressed or disabled alarm, with who did it and when it expires, so bypasses are not forgotten.
Read → GlossaryThe component that sends SCADA alarms as text messages via a local GSM modem or a cloud SMS API.
Read → GlossaryAlarming on vibration energy within specific frequency bands to catch early defects the overall misses.
Read → GlossaryAn alarm active far past a threshold like 24 hours, tracked as an ISA-18.2 health metric.
Read → GlossaryFires when a tag has not updated within its expected interval, catching a source that stopped refreshing while comms look up.
Read → GlossaryOne stays active for hours signalling an unresolved condition, the other flickers in and out - and what each pattern reveals.
Read → GlossaryAlarms enabled or disabled automatically by the equipment's operating state to prevent transition floods.
Read → GlossaryFixed-limit alarms - Hi/Lo and HiHi/LoLo levels, deadband and delay to prevent chatter, and how they differ from anomaly alarms.
Read → GlossaryWhy the alarm warns the operator and the trip acts automatically, and how the gap between them buys response time.
Read → GlossaryMechanical lost motion that stalls the valve on every reversal, and how to tell it apart from stiction.
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