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CWS220E 868 MHz Wireless Infrared Radiometer
Cable-Free Sensor
Wireless network means flexibility, cost savings, time savings
weather applications supported water applications supported energy applications supported gas flux and turbulence applications supported infrastructure applications supported soil applications supported


The CWS220E is a wireless version of our SI-111 infrared radiometer. It measures the surface temperature of an object without physical contact. This radiometer has an internal 868 MHz spread-spectrum radio that transmits data to a CWB100E Wireless Base Station or to another wireless sensor. The 868 MHz frequency is commonly used in Europe.

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Benefits and Features

  • Provides road surface, plant canopy, soil surface, snow surface, and water surface temperature measurements
  • Internal frequency-hopping, spread spectrum radio provides longer range and less interference
  • Battery powered
  • A reliable, low maintenance, low power method for making measurements in applications where cabled sensors are impractical or otherwise undesirable
  • Transmissions can be routed through up to three other wireless sensors
  • Measures surface temperature continuously in the field
  • Ideal for providing spatial averages
  • Compatible with CR800, CR850, CR1000, and CR3000 dataloggers


Technical Description

The CWS220E includes a thermopile, which measures surface temperature, and a thermistor, which measures sensor body temperature. The two temperature sensors are housed in a rugged body that contains a germanium window. It is battery powered using either alkaline batteries or a rechargeable battery and a solar cell.

The CWS220E can route its transmissions through up to three other wireless sensors. A datalogger is connected to the CWB100E base station for processing and storing its data. The CWS220E interfaces with a PC for configuration via the A205 CWS Sensor to PC Interface.

The calibration coefficients used for determining the target temperature by means of the Stefan-Boltzman equation are stored in the CWS220E at the time of calibration.

Why Wireless?

There are situations when it is desirable to make measurements in locations where the use of cabled sensors is problematic. Protecting cables by running them through conduit or burying them in trenches is time consuming, labor intensive, and sometimes not possible. Local fire codes may preclude the use of certain types of sensor cabling inside of buildings. In some applications measurements need to be made at distances where long cables decrease the quality of the measurement or are too expensive. There are also times when it is important to increase the number of measurements being made but the datalogger does not have enough available channels left for attaching additional sensor cables.


Weather Resistance IP67 rating for sensor and battery pack (Battery pack must be properly installed. Each sensor is leak tested.)
Operating Temperature Range -25° to +50°C
Operating Relative Humidity 0 to 100%
Power Source 2 AA batteries with a battery life of 1 year assuming sensor samples taken every 10 minutes. (Optional solar charging available.)
Average Current Drain 300 μA (with 15-minute polling)
Response Time < 1 s (to changes in target temperature)
Target Temperature Output Signal 60 μV per °C difference from sensor body
Body Temperature Output Signal 0 to 2500 mV
Optics Germanium lens
Wavelength Range 8 to 14 μm (Corresponds to atmospheric window.)
Field of View (FOV) 22° half angle
Absolute Accuracy
  • ±0.2°C (-10° to +65°C)
  • ±0.5°C (-40° to +70°C)
  • ±0.1°C (-10° to +65°C)
  • ±0.3°C (-40° to +70°C)
  • ±0.05°C (-10° to +65°C)
  • ±0.1°C (-40° to +70°C)
Dimensions 15 x 6 x 4.5 cm (5.9 x 2.4 x 1.77 in.)
Weight 270 g (9.6 oz)

Internal 25 mW FHSS Radio

Frequency 868 MHz
Where Used Europe
FHSS Channel 16
Transmitter Power Output 25 mW (+14 dBm)
Receiver Sensitivity -110 dBm (0.1% frame error rate)
Standby Typical Current Drain 3 μA
Receive Typical Current Drain 18 mA (full run)
Transmit Typical Current Drain 45 mA
Average Operating Current 15 μA (with 1-second access time)
Quality of Service Management RSSI
Additional Features GFSK modulation, data interleaving, forward error correction, data scrambling, RSSI reporting


Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.


Product Compatible Note
CR1000 (retired)
CR200X (retired)
CR216X (retired)
CR5000 (retired)
CR6 The CR6 datalogger must have data logger OS version 4.0 or higher.
CR9000X (retired)

Additional Compatibility Information


The CWS220E mounts to a mast or pole via the the 26054 bracket. It is mounted at an appropriate distance from the target where it can measure an individual leaf, a canopy, or any surface of interest. Because the CWS220E is wireless, it can be mounted in many locations that would be problematic for a cabled sensor.


Wireless Sensor Planner v.1.7 (30.5 MB) 08-08-2013

The Wireless Sensor Planner is a tool for use with Campbell Scientific wireless sensors.  It assists in designing and configuring wireless sensor networks.