User Manual

HOBO U14 Data Logger User Manual
2
PlotA:InternalTemperatureSensor
AccuracyandResolution
Specifications
LCD
Size 33x50.8mm(1.3x2inches)
Elements
 Temperatureandrelativehumiditysimultaneously
 °Cor°F(selectablewithinhostsoftware)
 Memoryremainingandbatterylevel
 FlashingALERTforout‐of‐limitsconditions(selectablewithinhostsoftware),whichstopsflashing
onoffloadorreturntonormalrange
Alarms
Setpoints Highandlowsetpointsforbothtemperatureandrelativehumiditywithselectabledelays
Resetoptions Alertconditionsresetonoffloadorreturntonormalrange
SelectableContactRelay NormallyClosedorNormallyOpen
Contactrating 48VDC,1Amax
Contactresistance Lessthan1Ohm
Range 0%LowBatteryRange
Communications
Method OffloadsdatatoPCorU‐ShuttleviaUSBcable
Speed Readoutfulllogger(64K)inlessthan30seconds
Timeaccuracy ±1minutepermonthat+20°C(+68°F)
Power 3AAAAlkalinebatteries,user‐replaceable
Dimensions 125x92x31mm(4.9x3.6x1.2in)
Weight 170g(6.0oz)withbatteries
Internal12‐BitTemperatureSensor
Measurementrange‐20°Cto+50°C(‐4°Fto+122°F)
Accuracy ±0.21°Cfrom0°to50°C(±0.38°Ffrom32°to122°F);±0.13°C(0.24°F)typical(seePlotA)
Resolution 0.02°C@25°C(0.04°F@77°F)(seePlotA)
Responsetime 15minutes(to90%inairflowof1m/sec)
TemperatureAccuracyDrift Negligible
Internal12‐BitRelativeHumiditySensor(Userreplaceable)
Measurementrange 0‐100%RH,‐20to50°C(‐4to122°F)
Accuracy +/‐2.5%from10%to90%RH(typical),toamaximumof+/‐3.5%includinghysteresis(seePlotB)
Resolution 0.03%RH@25°C(77°F)
Responsetime 2minutes(to90%inairflowof1m/sec)
AccuracyDrift <2%over5yearstypical
Hysteresis 1%Typical
ExternalSensors ForExternalSensorSpecifications,seethesensor’susermanual
BatteryLife Thebatterieswilllastoneyearintypicalconditions(loggingintervalsof≥1minutewithweekly
offloadsandaveragetemperaturesgreaterthan10°Cor+50°F).Frequentoffloadsand/orextreme
temperatureswillreducebatterylife.Attemperaturesbelowfreezing(0°Cor+32°F),batterieswill
typicallyrequirereplacementeverysixmonths.
Intheseconditionsthebatterylevelbargraph
shouldbecheckedregularly.SeeBatteryLevelIndicatorsonpage8.

TheCEMarkingidentifiesthisproductascomplyingwithallrelevantdirectivesintheEuropean
Union(EU).
TemperatureAccuracyandResolution
Themaximumreadingerrorfortheinternaltemperaturesensorsisshownatright.Thisisaworstcase
error.Inatypicallogger,temperatureerrorswillbesubstantiallylower.NISTcertificationof
temperatureaccuracyforsomesensorsisavailablefromOnset.Thetemperatureresolutionforinternal
sensorsisalsoshownat
right.Resol utionisthesmallestdifferencebetweenadjacenttemperaturesteps
thattheloggercanreport.Theloggerwilltypicallyexperiencelittleornoaccuracydriftunlessthe
electroniccomponentsortemperaturesensoraredamagedmechanicallyorbyexposureto
environmentalfactorsbeyondthespecifications,suchashighheatandhumidity.