Azbil DCP31 - Page 125

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Chapter 7. PARAMETER SETUP
•TheATLEDlightswhilereviewingthe
BR
valuewhensetto2.
•Donotsetto2whennormalcontrolisnotbeingcarriedoutdueto
inappropriatetuningofthePIDconstant,forexample.
Also,huntingismorelikelytooccurwhen
BR
issettoalarge
valueonquick-startinglines.Setthe
BR
valueto0thento2.
•Onheat/coolmodels,smart-tuningdoesnotfunction.

2 P I D
(2 degrees of freedom)
0: 2degreesoffreedomisdisabled.
1: 2degreesoffreedomisenabled.
•2degreesoffreedomisafunctionforimprovingtheresponseto
disturbanceduringsetupwithoutlosingconventionalcharacteris-
ticsatrise(orfall).
Whensetto1,optimumPIDconstantscanbesetindividuallyfor
inhibitingdisturbanceinadditiontoconventionalthePIDcon-
stant.
TheseconstantsaresetautomaticallyduringATexecution,andis
memorized.Theycanalsobesetandchangedindependently.
Inparticular,on2Goutputmodels,suppressingchangesinMVto
lessenthefrequencyofmotoroperationduringsetup,andmanu-
allyapplyingweakPIDdifferentialforinhibitingdisturbanceto
lengthenservicelife,forexample,proveseffective.
•ThesePIDareswitchedautomaticallybyapplyingfuzzyruleson
theslopebetweendeviationandPV.
•When
I
(resettime)issetto0,controliscarriedoutwithoutinte-
grationinallstatesregardlessofthesettingvalueof
DI
(distur-
banceinhibitresettime).
•Onheat/coolmodels,2degreesoffreedomdoesnotfunction.

D I F F
•ON-OFFcontroldifferential
WhenPissetto0.0onboth0Dand6Doutputmodels,controlisset
toON-OFFcontrol,andoperationalperiodatthattimeisset.
Dierential
gap
PV
OFF
ON
Reverse action
Dierential
gap
PV
OFF
ON
Direct action
SPSP