Delphin ProfiMessage - 4.7.14.1.2 Control paths

ProfiMessage
Typical formula for a standard PID controller:

Characteristic control system values
KS–processgain.dX/dYofasystemstepresponse.
Tu–delaytime
Tg–compensationtime
Tt–deadtime
W–inflectionpoint
KI–integralgain
TI–integraltime
4.7.14.1.2 Controlpaths
Tofindasuitablecontroller,youmustknowthecharacteristicsofthecontrolpaths
tobeinfluenced.
Acontrolpathisthatpartofasystembetweenthefinalcontrolelementforthecon-
trolquantity(theprocessquantitytobecontrolled)andthecontrolquantity's
measuringpoint.Thefinalcontrolelementandthemeasuringelementarealso
partofthecontrolpath.
Controlpathscanbefundamentallydividedintotwocategories:
l Controlpathswithcompensation:Whenacontrolorinterferencevariable
changes,thecontrolvariablesearchesforanewfinalvalue(steadystate).
Example:Flow,temperature,etc.
l Controlpathswithoutcompensation:Controlpathsthatdonotsearchfora
finalvalue(integratingcontrolpaths),areknownascontrolpathswithout
compensation.Example:Filllevel.
MostcontrolpathsconsistofPsystems(amplification/attenuation),oneormore
T1systems(lowpass)andifpossibleonedeadtime(runtime).PathswithPT1
propertiesarecalledfirstordercontrolpaths.ControlpathswithmultipleT1sys-
temscorrespondtonthordercontrolpaths.
Control paths with compensation have the following char-
acteristics:
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Delphin Technology AG
Dezember 2015
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