CS125
CS125
OrderablePresent Weather and Visibility Sensor
Pricing
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Configuration
- -25 to +60C, w/5m (17 ft) per Sensor**CS125-ST-5mPart Number: 44192
- -25 to +60C, w/10m (33 ft) per SensorCS125-ST-10mPart Number: 44194
- -25 to +60C, w/15m (50 ft) per SensorCS125-ST-15mPart Number: 44196
- -25 to +60C, w/30m (100 ft) per SensorCS125-ST-30mPart Number: 44198
- -40 to +70C, w/5m (17 ft) per Sensor**CS125-XT-5mPart Number: 44193
- -40 to +70C, w/10m (33 ft) per SensorCS125-XT-10mPart Number: 44195
- -40 to +70C, w/15m (50 ft) per SensorCS125-XT-15mPart Number: 44197
- -40 to +70C, w/30m (100 ft) per SensorCS125-XT-30mPart Number: 44199
Select a configuration to add to your quote
- Model:
- CS125
- Item Number:
- CS125
- Warranty:
- 2 years
Overview
The CS125 is an infrared forward-scatter visibility and present weather sensor for stand-alone use or with automatic weather stations including those for road, marine, and airport applications. The CS125 has an attached 5 m (16.4 ft) cable and DB9 connector.
Learn more about our CampbellAero™ Automated Weather Observing System (AWOS) Solution and our CampbellAero Software.
Key Advantages
Ideal for transportation applications
Technical Description
The CS125 uses the well-established forward scatter system for visibility measurement, using a 42° scatter angle, which gives accurate estimates of Meteorological Observable Range (M.O.R.) for fog and snow.
It identifies precipitation particles from their scattering properties and fall speeds, and combines this with a temperature measurement to identify the weather type. It has downward-pointing optics that reduce the risk of contamination of the optics and blockage with snow. Interference to the sample volume from the sensor by flow distortion or heat is minimized.
It also provides reliable present weather information in the form of SYNOP codes, including information on the intensity of precipitation. Accumulation can also be reported.
The CS125 uses continuous high-speed sampling to reduce errors during mixed-weather events and events that return intermittent signals, such as rain and hail, while still providing reliable readings during more stable events, such as fog and mist. The CS125 has high immunity to interference from the visible and infrared warning lights used to mark obstructions, such as wind turbines.
The sensor can be set to a lower sampling frequency to save power, if required.
The CS125 incorporates low-power dew prevention heaters, as well as higher-power anti-icing heaters for the hoods as standard. These heaters are automatically controlled to ensure operation in all weather, or they can be disabled individually to save power.
The CS125 continuously monitors its own status and will report internal faults and contamination or blockage of the sensor lenses. It also has two user-configurable alarm outputs that can be used to drive audio or visual alarms using solid-state relays.
The CS125 is certified by Deutscher Wetterdienst as suitable for use to control wind turbine obstruction light systems as specified by 506/04, General Administrative Rules for the Identification of Aircraft Obstructions.
Benefits
- High performance sensor at a competitive price
- Sensor design minimizes airflow disruption at measurement volume
- Simple field calibration using optional calibration kit
- Low power - suitable for remote application
- Automatic status check for faults or window contamination
- Incorporates automatic dew and hood heaters for all-weather operation
- Type certified for aviation use by the German Meteorological Service, Deutscher Wetterdienst (DWD)
Specifications
Operational
- Maximum Reported Visibility
- 100 km
(62.1 mi)
- Minimum Reported Visibility
- 5 m
(16.4 ft)
- Resolution
- 1 m
(3.28 ft)
- Outputs
- Present and past weather: identifies as standard mist, fog, drizzle, freezing drizzle, drizzle and snow, rain, freezing rain, rain and drizzle, rain and snow, and snow.
57 SYNOP present weather codes and associated METAR and NWS present weather codes - hail detection; past weather codes.
- Accuracy
- ±8%
(up to 600 m [1968.5 ft])
±10%(600 to 10,000 m [1968.5 to 32,808.4 ft])
±15%(10,000 to 15,000 m [32,808.4 to 49,212.6 ft])
±20%(above 15,000 m [49,212.6 ft])
- Precipitation Detection Sensitivity
- 0.05 mm/h
- Accumulation Reporting Range
- 0 to 999.9 mm
(0 to 39.37 in.)
- Accumulation Accuracy
- ±15%
(against factory calibration standards in the laboratory, for liquid precipitation)
- Accumulation Resolution
- 0.1 mm
(0.0039 in.)
- Rain Intensity Range
- 0 to 999.9 mm/h
(0 to 39.37 in./h)
(The maximum intensity reported is dependent on the mixture of precipitation falling.) - Intensity Accuracy
- ±15%
(against factory calibration standards in the laboratory, for liquid precipitation)
- Intensity Resolution
- 0.01 mm/h
(0.00039 in./h)
- Operating Temperature Range
- -25° to +60°C
(standard)
- Extended Operating Temperature Range
- -50° to +70°C or -40° to +70°C
- Operating Humidity
- 0 . . . 100%
- Operating Wind Speed
- Up to 60 m/s
- Sensor Sealing
- Rated to IP66
- Total Unit Power
- Less than 3 W while sampling continuously
(including dew heaters)
Mechanical
- Material
- Stainless steel and hard-anodized aluminum powder-coated
- Mountings
- Stainless-steel clip on V-bolt mounting to pole with diameter of 32 to 52.5 mm
(1.26 to 2.07 in.)
- Mounting Pole
- An optical mounting pole is available to place the sample volume at 1.5 m (4.9 ft), as recommended by the WMO.
- Frangible Mast
- Frangible masts are available to customer requirements to meet ICAO recommendations (typically placing the sample volume at 2.5 m [8.2 ft]).
- Visibility Sensor Dimensions
- 540 x 640 x 246 mm
(21.26 x 25.2 x 9.7 in.) including mount
- Cable Length
- 5 m
(16.4 ft)
- Sensor Weight
- ~3 kg
(6.61 lb) dependent upon mounting system
Electrical
- -NOTE-
- Lower power states can be achieved by less frequent sampling and remote control of heaters.
Optional power supplies with battery backup available.
Connectors in place of flying leads are available.
A low-voltage shutdown level can be set to prevent backup batteries from being damaged. - Electronics Supply Voltage
- 7 to 30 Vdc
- Hood Heater Supply Voltage
- 24 V
(dc or ac)
- Hood Heater Power
- 2 x 30 W
(total of 60 W)
- Dew Heater Power
- 2 x 0.6 W
(total of 1.2 W)
Interface
- 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)
Optical
- -NOTE-
- Lens contamination circuity monitors both the source and detector lenses for contamination/blockage at 1 s intervals.
The sensor can be configured to adjust 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. - Emitter Light Frequency
- 850 nm
Accessories
(6)44157
3.8 A 24 V NEC Class 2 Power Supply Kit
Orderable40062
High-Grade Calibration Kit for CS120/A or CS125
Orderable28680
Configuration Cable for CS120/A or CS125
Orderable39131
DIN Rail Terminal Kit with 2 Terminals and 6 Wires
Orderable39802
DIN Rail Terminal Kit with 4 Terminals and 9 Wires
Orderable40062
High-Grade Calibration Kit for CS120/A or CS125
Orderable
Common Accessories
(10)HygroVue 5
Digital Temperature and Relative Humidity Sensor
The HygroVUE™5 Temperature and Relative Humidity Sensor is designed for general meteorological and environmental monitoring applications. It utilizes the SDI-12 communications protocol to communicate with any SDI-12 recorder, simplifying installation and programming. The sensing element is easily changed in the field, reducing downtime and calibration costs. It is the entry-level sensor in the HygroVUE™ line of relative humidity and temperature sensors.
Orderable41303-5A
6-Plate Solar Radiation Shield
The 41303-5A is a naturally aspirated, 6-plate radiation shield. Its louvered construction allows air to pass freely through the shield, serving to keep the probe at or near ambient temperature. The shield's white color reflects solar radiation.
OrderableRAD06
6-Plate Solar Radiation Shield
The RAD06 uses a double-louvered design that offers improved sensor protection from driving rain, snow, and insect intrusion. It also has lower self-heating in bright sunlight combined with higher temperatures (> 24°C (~75°F)) and low wind speeds (< 2m/s (~4.5 mph)), providing a better measurement.
Orderable28680
Configuration Cable for CS120/A or CS125
The 28680 cable allows the visibility sensor to be connected to a PC for configuration. This cable is 3 m (9.8 ft in length).
Orderable44157
3.8 A 24 V NEC Class 2 Power Supply Kit
The 44157 is an optional 24 Vdc power supply kit used to supply power only to the visibility sensor's 24 Vdc hood heaters. A 24 Vdc battery is purchased separately. Choose the -UL option if the power supply needs to be UL approved.
OrderableCS140
Background Luminance Sensor
The CS140 is a high-quality background luminance sensor. It provides the luminance data required to assess the visibility range for lights such as runway lights or warning lights.
Orderable34296
CS140 Maintenance Cable
The 34296 cable, used with the CS140 Background Luminance Sensor, forces communications to RS-232 38400 baud, and sensor id “0.” The CS140 continues to draw power from the existing power source. After the sensor is removed from its power source, the sensor returns to its previous communication address and settings.
Orderable34295
CS140 Calibrator
The CS140 Calibrator is a high-quality device to generate a known luminance level for calibrating a CS140 Background Luminance Sensor. It is powered from the CS140 supply and is used while in communication with it.
Orderable39802
DIN Rail Terminal Kit with 4 Terminals and 9 Wires
The 39802 provides the needed DIN rail terminals, separator, and wires to connect any product to a data logger or other peripheral that requires nine wires for connection. This kit provides the following wires: black, red, green, light blue, clear (2), white, 16 AWG black, and 16 AWG red. The color-coding of these wires matches the wire coloring of the product for ease in connection, maintenance, and troubleshooting.
Orderable40062
High-Grade Calibration Kit for CS120/A or CS125
The 40062 is a customer field-calibration kit for the CS120/A and CS125 visibility and present weather sensors. The kit consists of a calibration disc, two bungs (or stoppers), and a foam-lined case. The calibration disc comprises a neutral-density (ND) filter media with a ground glass disc mounted in an anodized aluminum frame, which simulates low visibility (below 1 km or 3,280.8 ft) as well as perfect visibility (75 km or 46.6 mi). The foam bungs block the optical paths, allowing verification and/or adjustment of the calibration constants held within the system. The calibration disc is designed to mount in a precise and specific location on the CS120/A or CS125 sensor for ease of use and to ensure consistent results. The foam-lined case protects the disc and ensures the bungs are not compressed, which would compromise the accuracy of the calibration.
Orderable
Ships With
(2)- 5 m Sensor Cable from original mfg
- 5 m Hood Heater Cable from original mfg
Compatibility
Compatible Products
(2)Related Resources
Case Studies

Central Africa: Airport Weather System
Upgrading airport weather system
Sao Tome International Airport, western coast of Central Africa
July 6, 2016
View
Utah: Road Weather Management
Roadway condition data to support weather forecast operations and winter maintenance practices
Utah
May 31, 2016
View
Ontario: Municipal Airport Automated Weather Observation System (AWOS)
Air ambulance, private jet traffic, and chartered flights
Manitouwadge, Ontario, Canada
March 17, 2025
View
Portugal: Cloud Base and Visibility Sensors for Military Aviation
Support of military air operations
Portugal
June 25, 2015
View
Showing 4 of 5 results
See all Case StudiesDocuments
- Manual
CS120A and CS125 Visibility and Present Weather Sensors
October 2025
View Document - Compliance
40062 EU Declaration of Conformity
May 2022
View Document Central Africa: Airport Weather System
View Document- Brochure
CS125 Present Weather Sensor
March 2026
View Document
Showing 4 of 9 results
See all DocumentsDownloads
- CR1000X CS125 example programsv1
March 18, 2020
Software ApplicationsCR1000X programs that read continuous data and polled data and use the SET, SETNC, and GET commands. The program that uses the SETNC command powers the CS125 hood heaters when needed according to the dew point. A HygroVUE5 Air Temperature and Relative Humidity Sensor provides the measurements used in the dew point calculation.
- CS125 and CS120A OSv17Login required
June 26, 2023
OS and FirmwareCampbell Scientific has introduced a new operating system, OS 17, for the CS120A visibility sensor and CS125 present weather sensor. It is backwards compatible and is easily installed on all CS120A and CS125 sensors (but not older CS120 sensors). OS 17 is available free of charge and can be downloaded here or supplied by email on request. Upgrade to OS 17 is recommended.
