User Guide - Eurotherm Ltda

nanodac RECORDER/CONTROLLER: USER GUIDE4.4.3 Alarm 1 menuAllows the alarm characteristics for Alarm 1 to be configured. The figure below shows a typical configurationpage (expanded for clarity). Actual configuration parameters are context sensitive.Channel.1.Alarm1TypeStatusThresholdHysteresisLatchBlockDwellAcknowledgeActiveInactiveN.acknowledgedAcknowledgementInhibitAbs HighActive Not ackd35.00°C5.00°CManualOff00:00:00NoYesNoYesNoFigure 4.4.3 Typical alarm 1 configuration menuTypeStatusThresholdReferenceDeviationSelect an alarm type from: ‘Off’, ‘Abs. High’ (absolute high). ‘Abs. Low’ (absolute low),‘Dev. High’ (deviation high), ‘Dev. Low’ (deviation low), ‘Dev. Band’ (deviation band),‘Rise ROC’ (rate-of-change: rising), ‘Fall ROC’ (rate-of-change: falling), ‘Digital High’,‘Digital Low’. See ‘Alarm types’, below, for definitions.Read only. This shows that the alarm is Off, Active, SafeNotAcked or ActiveNotAcked.For ‘Auto’ and ‘Manual’ alarms only, ‘SafeNotAcked’ means that the alarm triggersource has returned to a non-alarm state, but the alarm is still active because it has notbeen acknowledged. Similarly, ‘ActiveNotAcked’ means that the source is still activeand the alarm has not been acknowledged. Always shows ‘Off’ when the alarm is inhibited(see below).For absolute alarms only, this is the trip point for the alarm. For absolute high alarms, ifthe threshold value is exceeded by the process value (PV) of this channel, then thealarm becomes active, and remains active until the PV falls below the value (threshold -hysteresis). For absolute low alarms, if the PV of this channel falls below the thresholdvalue, then the alarm becomes active and remains active until the PV rises above(Threshold + Hysteresis).For deviation alarms only, this provides a ‘centre point’ for the deviation band.For ‘deviation high’ alarms, the alarm becomes active if the process value (PV) risesabove the value (Reference + Deviation) and remains active until the PV falls below (Reference+ Deviation - Hysteresis).For ‘deviation low’ alarms, the alarm becomes active if the process value (PV) falls belowthe value (Reference - Deviation) and remains active until the PV rises above (Reference- Deviation + Hysteresis).For ‘deviation band’ alarms, the alarm is active whenever the process value (PV) lies outsidethe value (Reference ± Deviation) and remains active until the PV returns to withinthe band, minus or plus Hysteresis as appropriate.For deviation alarms only, ’Deviation’ defines the width of the deviation band, each sideof the Reference value, as described immediately above.HA030554Issue 7 Nov 12Page 85