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Humidity - 4-20mA Wall Sensors

  • 3% accuracy
  • 4-20mA and 0-5/10V RH/Temp (RTD/thermistor options available)
  • Optional LCD and Override
  • Field replaceable element


  • HVAC room humidity and temperature measurement and control
  • Energy management/building control


The HW Series is designed to monitor indoor relative humidity and temperature conditions and provide a proportional 4-20mA or 0-5/10V output. The sensor includes a field replaceable RH sensing element and optional add-on features including LCD, override button, temperature transmitter and RTD/thermistors to match project requirements. The LCD version includes options for provisional offsets for temperature (+/-5o) and RH readings (+/-5%) for in-field calibration.

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Easy to install and maintain

  • Dual 4-20mA and 0-5/10V output (jumper selectable)

3% RH field replaceable sensor

  • On-board temperature compensation for RH eliminates temperature coefficient errors achieving excellent measurement accuracy, high repeatability and offset stability

Customize to meet project requirements

  • Optional LCD with provisional offsets for temperature (+/-5o) and RH readings (+/-5%) for in-field calibration
  • Select analog temperature transmitter or specified RTD/Thermistor for temperature sensing
  • Override button available


  • Industry leading 7-year limited warranty / 2-year RH element
Power supply 3-wire voltage mode (0-5/10v) 12-30vdc/24vac(1), 15mA max
2-wire current mode (4-20mA) 12-30vdc, 30mA max
Outputs RH and Temperature (option) 3-wire 0-5/10v(4) or 2-wire 4-20mA
Output Scaling RH 0-100% RH
Temperature (jumper selectable) 32-122oF (0-50oC) or -40-140oF (-50-50o C)
Thermistor/RTD Options   See ordering table
Relative Humidity            Accuracy  +/-3% over 20 to 75% range
Resolution  0.05%RH 
Hysteresis  +/-1%RH 
Non-linearity  Factory linearized <1%RH 
Temperature coefficient  Fully compensated by on-board sensor 
Response Time(2)  30s 
Output update rate  2s 
Operating range 

0 to 100%RH (non-condensing)

Long term drift   <0.05%RH per year 
Operating conditions(3)    -20 to 60oC @ RH > 90%
 -20 to 70oC @ RH = 50%
 Temperature (transmitter)       Accuracy (-20 to 70oC range)  <+/-2oC; 0.5oC @ RH > 90%
 Resolution  0.01oC
 Repeatability  +/-0.1oC
 Response Time(2)  30s
 Output update rate  2s
 Operating range  -40 to 70o

(1) One side of transformer secondary is connected to signal common. Dedicated transformer is recommended.
(2) Time for reaching 63% of reading at 25oC at 1 m/s airflow.
(3) Long term exposures to conditions outside normal range or high humidity may temporarily offset the RH reading (+3%RH after 60 hours).
(4) 15-30vdc/24vac power supply voltage required for 10 volt output.