This product is no longer available and has been replaced by: CS120A. Some accessories, replacement parts, or services may still be available.
CS120 Atmospheric Visibility Sensor
Services Available
Repair Yes
Calibration Yes
Free Support Yes


The CS120 uses tried-and-tested, infrared forward-scatter technology, and uses the proven 42° scatter angle to report meteorological observable range (MOR) for fog and snow in the range 10 to 30,000 m. It combines a high specification with a very competitive price. The CS120 is ideal for stand-alone applications or in combination with automatic weather stations in road, aviation, solar-energy, and wind-energy environments.

Note: Campbell Scientific does not recommend using the CS120 for marine applications.

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Beneficios y características

  • High-performance sensor at a competitive price
  • Incorporates automatic dew and hood heaters for all-weather operation
  • Simple field calibration using optional calibration kit
  • Low power - suitable for remote applications
  • Automatic status check for faults or window contamination
  • Sensor design minimizes airflow disruption at measurement volume


Descripción técnica

Compared to many such sensors the CS120 design means that visibility is being measured in a relatively clean space because the position of the heads and body minimize disturbance of the airflow at the measurement volume.

The CS120 uses continuous high-speed sampling, which improves the accuracy of the measurements taken during mixed weather such as rain and hail, while providing reliable readings during more stable events such as fog and mist. High speed sampling also allows the sensor to better respond to suddenly changing conditions.

The CS120 has several design features that keep its optics clean. Downward facing optics minimizes dirt and snow build up. Low powered heaters prevent the formation of dew, and a higher-powered heater prevents the formation of ice.

The sensor is very power efficient, drawing just 3 W during normal operation including the dew heaters; power can be reduced further by reducing the sample rate and manual control of the heaters.


Measurement Description Meteorological Observable Range (MOR)
Signal Type/Output RS-232, RS-485
Maximum Reported Visibility 32 km (~20 mi)
Minimum Reported Visibility 12 m (~39 ft)
Accuracy (0 to 10,000 m) ±10%
Accuracy (10,000 to 20,000 m) ±20%
Operating Temperature -25° to +60°C
Operating Humidity 0 to 100%
Wind Speed Up to 60 m/s
Sensor Sealing Rated to IP66
Mounting Stainless-steel V-bolt mounting to pole with OD of 32 to 52.5 mm (1.25 to 2 in.)
Dimensions 447 x 640 x 246 mm (17.6 x 25.2 x 9.7 in.)
Weight ~3 kg (6.6 lb) depending upon mounting system used


  • A low-voltage shutdown level can be set to prevent back-up batteries being damaged.
  • Lower power states can be achieved by less frequent sampling and remote control of heaters.
Electronic Supply Voltage 8 to 30 Vdc
Hood Heater Supply Voltage 24 Vdc or Vac
Hood Heater Power 2 x 30 W (total of 60 W)
Total Unit Power < 3 W while sampling continuously (including dew heaters)


Serial Interface RS-232 or RS-485
Serial Data Rates 1200 to 115,200 bps (38,400 bps default rate)
Alarm Outputs 2 x 0 to 5 V outputs, 32 mA (max)


Emitter Light Frequency 850 nm
Lens Contamination Circuitry Monitors both the source and detector lenses for contamination/blockage at 1 s intervals. Sensor adjusts its calibration for low to moderate window contamination.
Light Source Stability Control Ensures stable operation through variations in temperature and with sensor aging. Corrected at 1 s intervals.


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


Product Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR9000 (retired)
CR9000X (retired)

Documentos relacionados


CS120 Firmware v.6 (1.51 MB) 10-08-2012

Includes the current CS120 firmware and the CS120 support files for the Device Configuration Utility.

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Articles and Press Releases