Category
Humidity Transmitters
Humidity and temperature transmitters for rooms, ducts, outdoor use and wet and dry bulb measurement.
A humidity transmitter measures relative humidity, and usually temperature too, as a continuous signal so a controller can keep a space, duct or process within the right range. Too dry brings static and discomfort; too humid brings mould, condensation and corrosion. Our range covers room, duct, outdoor and wet and dry bulb transmitters from Produal and Shinko.
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Humidity Subcategories
6 Products · Humidity
Duct Humidity & Temperature - KLK
Outdoor Humidity And Temperature Transmitter - KLU 100
Rh+T Wet & Dry Bulb Transmitter
Room Humidity Transmitter KLH
Room Humidity Transmitter RTX-RH
Touchscreen Room Transmitter RTX-D-RH
Selection guide
Humidity Transmitters Guide
How a humidity transmitter works
Most transmitters use a capacitive polymer sensor: the polymer absorbs moisture from the air, which changes its electrical capacitance in proportion to the relative humidity. Electronics convert that change into a standard output signal such as 4 to 20 mA or 0 to 10 V. Wet and dry bulb transmitters instead compare two temperature readings, one from a dry sensor and one from a sensor kept wet by a wick, and calculate humidity from the cooling effect evaporation has on the wet sensor.
Where our humidity transmitters are used
- Buildings: room, duct and outdoor humidity for HVAC control, using the Produal KLH, KLK, KLU 100 and RTX-RH.
- Demanding areas: factories, warehouses, parking garages, unheated areas, spas and indoor swimming pools, using the Produal KLU 100, which is built to hold up in constant moisture.
- Wet and dry bulb measurement: the Shinko Rh+T transmitter, for applications that specifically need this method rather than a capacitive sensor.
- Also measures: all of these transmitters also measure temperature, so one device and one installation point covers both readings rather than fitting two separate sensors.
Choosing a transmitter
- Mounting location: start with where it will be installed, room, duct or outdoor.
- Output: check the output your controller needs.
- Display: the Produal RTX-D-RH has a 2.8 inch touchscreen for rooms where occupants or staff should see the reading directly.
- Full range: see Temperature and Humidity Transmitters for the full model list, or Humidity Transmitters for HVAC and BMS for building automation applications such as clean rooms and data centres.
FAQ
Common questions
What is the difference between relative humidity and dew point?
Relative humidity is how much moisture the air holds compared with the most it could hold at that temperature. Dew point is the actual temperature at which that moisture would start to condense. Relative humidity changes with temperature even if the moisture content stays the same, while dew point does not.
Which transmitter suits a swimming pool hall?
The Produal KLU 100, which is designed for demanding conditions including spas and indoor swimming pools. Its longer probe keeps the sensing element away from heat given off by the electronics, which helps keep readings accurate in warm, humid air.
Do you have a humidity transmitter with a display?
Yes. The Produal RTX-D-RH touchscreen room transmitter has a 2.8 inch screen showing live humidity and temperature readings, so occupants or facilities staff can check conditions without a separate BMS terminal.
What is a wet and dry bulb humidity transmitter?
It calculates humidity from the difference between two temperature sensors: one dry, one kept wet by a wick. As air passes over the wet sensor, evaporation cools it, and the size of that cooling effect depends on humidity. The Shinko Rh+T transmitter uses this method.
Can one transmitter measure both humidity and temperature?
Yes. All the humidity transmitters on this page, from Produal and Shinko, measure temperature as well as relative humidity, so you get both readings from a single device and installation rather than fitting two separate sensors.
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