SRC RANGER 4000 S - Setting Hourly Maximum Rain and Rain Alarm Level

RangerSInstallationandtroubleshooting
23
SettingHourlyMaximumRainandRainAlarm
Level
TheRanger4000Sallowsfortwoprecautionswhenyouexperiencerain:
Youcansetathresholdvalueforhowmuchitshouldrainbeforetherain
alarmwillbeactivated.Hereishowthiscalculationisdone:
• BasedonhistoricalETdataforthearea,thecontrollerknowshow
muchwaterisevaporatingperdayduringthecurrentseason.
• TheRanger4000Sassumesthat75%ofthedailyETisevaporating
between8and20,andtheremaining25%between20and8.
• Whentheamountofrainexceedstherainalarmlevelyoudefine,
therainalarmisactivated.
• Now,basedonthehistoricalETdatathecontrollerwillcalculate
howmuchrainwillevaporate,andmappingthisnumberagainstthe
knownamountoffallenrain,thecontrollerwillintelligentlyknow
whenitissafetoturnofftherainalarm(i.e.whenenoughrainhas
evaporatedthatwearebelowyourdefinedalarmlevel.)
• Thesoilholdingvalueisalsoaparameter:sinceyoucannever
benefitfrommorerainthanthesoiliscapableofholding,therain
alarmwillnotstayonforeverafterafewdaysofintensiverain.
• Ifitrainsintensivelyformorethananhouryoumaygetsomuch
waterthatthesoilcannotbenefitfromallofit‐theexcesswater
willsimplyrunoffthesurface.SoifyourunprogramsinET
correctedmode,thecontrollerwon'tsubtractalloftherainfrom
Note:IfyouhavenotprovidedanyhistoricalET,adefaultof5
mmperdayisused.SeemoreintheRanger4000UserManual.