Limited Availability ›
This product has limited availablity. Some accessories, replacement parts, or services may still be available when it is no longer available.
CWS900E 868 MHz Configurable Wireless Sensor Interface for Europe
Cable-Free Sensor
Adapts wide variety of sensors to wireless net
weather applications water applications energy applications gas flux & turbulence applications infrastructure applications soil applications


With a CWS900E, you can use a variety of sensors in a wireless sensor network. (See the Compatibility information on the web page.) It contains an internal 868 MHz spread-spectrum radio that transmits data to the CWB100E Wireless Base Station or to another wireless sensor. The frequency of the CWS900E's internal radio is commonly used in Europe.

Read More

Benefits and Features

  • Allows a wide variety of sensors to be used in a wireless network
  • 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

This product will be discontinued as of 10 April 2017. Please review the CWS-Series and CWB-Series Discontinuation Notice for further details. 


Detailed Description

The CWS900E has a sealed connector for attaching one rain gage, wind sensor, temperature/RH probe, or another low power sensor. It measures analog voltages, low level AC, pulse counts, and can supply an excitation voltage for powering some sensors or making bridge measurements. The type of measurement that the sensor performs is configured using Wireless Sensor Planner, Network Planner, or DevConfig software. The CWS900E interfaces with the PC for configuration via the A205 CWS Sensor to PC Interface.

The CWS900E can route its transmissions through up to three other wireless sensors. A datalogger is connected to the CWB100E base station for processing and storing the CWS900E's data.

The CWS900E is battery powered using either alkaline batteries or a rechargeable battery and a solar cell.

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.

Note: The internal radio is not designed to move a lot of data quickly. It takes 15 to 30 seconds per hop when moving data from a sensor, through a sensor used as a repeater, and ending up at the base radio. Going through three repeaters could take a data packet anywhere from 45 to 90 seconds to get to the base radio.


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 Range 0 to 100% (non-condensing)
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 and depending on attached sensor)
Analog Channels
  • SE1, SE2, SE3 (single-ended)
  • DF (differential)
Analog Input Range -1 to +2.5 Vdc
Resolution 0.3 μV
Excitation Voltage 2.5 V, 3.3 V, 5.0 V (20 mA maximum)
Excitation Voltage Accuracy ±2% (-35° to +70°C)
Low-Level AC Input 20 mV minimum (10 kHz maximum frequency)
Temperature Accuracy ±0.2ºC
Analog Measurement Accuracy
  • ±(0.02% of reading + 2 µV) (0° to 50°C)
  • ±(0.05% of reading + 2 µV) (-35° to +70°C)
Bridge Measurement Accuracy (+2.5 V excitation only)
  • ±(0.03% of reading + 3 µV) (0° to 50°C)
  • ±(0.07% of reading + 3 µV) (-35° to +70°C) Not including sensor and measurement noise, and external bridge resistor errors.
Dimensions 15 x 6 x 4.5 cm (5.9 x 2.4 x 1.77 in.)
Weight 184 g (6.5 oz)

Switch Closure

Maximum Count Rate 100 Hz
Minimum Open Time 5 ms
Minimum Closed Time 5 ms
Maximum Bounce Time 4 ms
Maximum Number of Counts Records 1,000,000 counts before it rolls over.

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


Datalogger Considerations

Compatible Datalogger Operating Systems

  • CR800-Series: CR800.Std.21 and higher
  • CR1000: CR1000.Std.21 and higher
  • CR3000: CR3000.Std.21 and higher
  • CR6: Version 4.0 and higher

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR9000X CR6

Compatible Retired Dataloggers

None of our retired dataloggers are compatible.


One sensor can be connected to the CWS900E. Sensors with the -CWS option will include a connector that mates with the CWS900E. Alternatively, a sensor can connect with the CWS900E via the A150 Desiccant Case (see bottom of page).

Temperature Probes with -CWS Option

107 108 109 109SS 110PV 43347 Thermocouples

Relative Humidity Probes with -CWS Option

CS215 HMP60 HMP155A HC2S3

Wind Sensors with -CWS Option

014A 27106T 03002 034B 05103 05103-45 05106 05305 WINDSONIC CSAT3

Rain Sensors with -CWS Option

TE525 TE525WS TE525MM TB4 TB4MM CS700 CS700H 52202

Solar Sensors with -CWS Option

CS300 LI200S LI200X LI190SB LP02 CMP3 CMP6 CMP11 CMP21 Radiometers

Water Quality Sensors with -CWS Option


Other Sensors with -CWS Option

  • LWS Leaf Wetness Sensor
  • HFP01 Soil Heat Flux Plate

A150 Desiccated Case

The A150 Desiccated Case has a -CWS cable termination option. It allows our CS450 and CS455 pressure transducers or other sensors that have a vented cable to be connected to the CWS900E. Sensors that measure analog voltages, frequency, and pulse can also use the A150 to connect with the CWS900E.


CWS900 Firmware v.5 (448 KB) 03-30-2016

Latest firmware for the CWS900.  

View Update History

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.

Frequently Asked Questions

Number of FAQs related to CWS900E: 4

Expand AllCollapse All

  1. To incorporate a sensor that is compatible with wireless sensor interfaces into a wireless network, a CWS900-series wireless sensor interface is needed, as well as an A205 CWS-to-PC interface to configure it.