ProfiMessage
Latch
Status D C (clock) Clr (clear) Q
1 X X H L
2 D ↑ L D
2 D H L D(transparent)
3 X L L Previousstatus
4.7.6 Limitvalue
Thissoftwarechannelmonitorsthespecifiedsourcechannel.Theresult,i.e.the
outputsignalofthelimitvaluechannel,is"High"whenthespecifiedalarmcon-
ditionsaremet.
Thefollowingformsofmonitoringareavailable:
Mode Alert when
Overrun
thevalueisabovethespecifiedrangeorabovethe
threshold
Underrun
thevalueisbelowthespecifiedrangeorbelowthe
threshold
Bandmon-
itoring
thevalueisoutsidethespecifiedrange(threshold±band-
width)
Bandviolation
thevalueiswithinthespecifiedrange(threshold±band-
width)
Constancy
valueschangebymorethanthebandwidthduringlag
time.
Inaddition,youcanalsosetnotriggeringforwire-breaksatthesource.Theset-
tingisonlyforsources(sensors)whichcanhavewire-breakmonitoring.
Forallinput,eitherenterafixedvalue(Manual value)orspecifyachannelthat
deliversthevalue.Itispossibletodynamicallychangethelimitvaluesduring
measurement.
Threshold isthedecisivevalueinmonitoring.
Hysteresis:Hysteresispreventsthealarmbeingrepeatedlyactivatedforsmallfluc-
tuationsaroundthethresholdvalueinthemonitoredsignal.Dependingonswitch
direction,thehysteresisliesbelowthethreshold(foroverruns)orabovethe
threshold(forunderruns).Seeimages.Thehysteresisisespeciallybeneficialfor
small(noise)signals.TheDelayoptionoffersanalternative.
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Delphin Technology AG
Dezember 2015
ProfiMessage Manual