Danfoss 087H3803 User Manual

5.5Returnlimit
Thereturntemperaturelimitationisbasedontheoutdoor
temperature.Typicallyindistrictheatingsystemsahigherreturn
temperatureisacceptedatadecreaseinoutdoortemperature.The
relationshipbetweenthereturntemperaturelimitsandoutdoor
temperatureissetintwocoordinates.
Theoutdoortemperaturecoordinatesaresetin'HighToutX1'
and'LowToutX2' .Thereturntemperaturecoordinatesaresetin
'HighlimitY2'and'LowlimitY1'.
Thecontrollerautomaticallychangesthedesiredflowtemperature
toobtainanacceptablereturntemperaturewhenthereturn
temperaturefallsbeloworgetshigherthanthecalculatedlimit.
ThislimitationisbasedonaPIregulationwhereP('Infl.'factor)
respondsquicklytodeviationsandI('Adapt.time')responds
slowerandovertimeremovesthesmalloffsetsbetweenthe
desiredandactualvalues.Thisisdonebychangingthedesired
flowtemperature.
X
=
Outdoortemperature
Y
=
Limitationtemperature
#X1#
=
HighTout(1x031)
#X2#
=
LowTout(1x033)
#Y1#
=
Lowlimit(1x032)
#Y2#
=
Highlimit(1x034)
Thecalculatedlimitisshowninbrackets()inthemonitoringdisplay.
Seethesection"Monitoringtemperaturesandsystemcomponents".
DHWcircuit
Thereturntemperaturelimitationisbasedonaconstant
temperaturevalue.
Thecontrollerautomaticallychangesthedesiredflowtemperature
toobtainanacceptablereturntemperaturewhenthereturn
temperaturefallsbeloworgetshigherthanthesetlimit.
ThislimitationisbasedonaPIregulationwhereP('Infl.'factor)
respondsquicklytodeviationsandI('Adapt.time')responds
slowerandovertimeremovesthesmalloffsetsbetweenthe
desiredandactualvalues.Thisisdonebychangingthedesired
flowtemperature.
X
=
Returntemperature
#1#
=
Limitationtemperature
#2#
=
Negativeinfluence(1x035)whenreturntemp.getshigherthan
limit.temp.
#3#
=
Negativeinfluence(1x036)whenreturntemp.getslowerthan
limit.temp.
#4#
=
Positiveinfluence(1x036)whenreturntemp.getslowerthanlimit.
temp.
#5#
=
Positiveinfluence(1x035)whenreturntemp.getshigherthan
limit.temp.
Ifthe‘Infl.’factoristoohighand/orthe‘Adapt.time’toolow,thereis
ariskofunstablecontrol.
VI.GU.L2.02
©Danfoss|2017.09|115
OperatingGuideECLComfort210/296/310,applicationA275/A375

Danfoss 087H3803 Specifications

General

Brand	Danfoss
Model	087H3803
Category	Controller
Language	English