CS616
CS616
OrderableConfigurableGSA30 cm Water Content Reflectometer
Lowest cost.
Pricing
Configuration
Sign in for option pricing- w/3m per Sensor -PF w/ Ferrules on WiresCS616-3m
- w/5m per Sensor -PF w/ Ferrules on WiresCS616-5m
- w/10m per Sensor -PF w/ Ferrules on WiresCS616-10m
- w/20m per Sensor -PF w/ Ferrules on WiresCS616-20m
- w/30m per Sensor -PF w/ Ferrules on WiresCS616-30m
Select a configuration to add to your quote
- Model:
- CS616
- Item Number:
- 45051
- Warranty:
- 1 year
- Lead time:
- 14 days
Overview
The CS616 measures the volumetric water content (VWC) of porous media (such as soil) from 0% to saturation. The probe outputs a megahertz oscillation frequency, which is scaled down and easily read by a Campbell Scientific data logger.
Key Advantages
Designed for long-term monitoring
Technical Description
The CS616 is comprised of two 30-cm-long stainless-steel rods connected to the measurement electronics. The circuit board is encapsulated in epoxy, and a shielded four-conductor cable is connected to the circuit board to supply power, enable the probe, and monitor the output.
The CS616 uses the time-domain measurement method to measure VWC; a reflectometer (cable tester) such as the TDR200 is not required. This method consists of the CS616 generating an electromagnetic pulse. The elapsed travel time and pulse reflection are then measured and used to calculate soil volumetric water content.
Response Characteristics
The signal propagating along the parallel rods of the CS616 is attenuated by free ions in the soil solution and conductive constituents of the soil mineral fraction. In most applications, the attenuation is not enough to affect the CS616 response to changing water content, and the response is well described by the standard calibration. However, in soil with relatively high soil electrical conductivity levels, compacted soils, or soils with high clay content, the calibration should be adjusted for the specific medium. Guidance for making these adjustments is provided in the instruction manual.
Benefits
- Compatible with most Campbell Scientific data loggers
- High accuracy and high precision
- Fast response time
- Designed for long-term unattended water content monitoring
- Compatible with AM16/32-series multiplexers, allowing measurement of multiple sensors
- Probe rods can be inserted from the surface or buried at any orientation to the surface.
Specifications
- Measurements Made
- Volumetric water content (VWC) of porous media (such as soil)
- Measurement Range
- 0% to saturation
- Water Content Accuracy
- ±2.5% VWC
(using standard calibration with bulk EC of ≤ 0.5 dS m-1, bulk density of ≤ 1.55 g cm-3, and measurement range of 0% to 50% VWC)
- Required Equipment
- Measurement system
- Soil Suitability
- Long rods and lower frequency are well-suited for soft soil with low electrical conductivity (< 2 dS/m).
- Rods
- Not replaceable
- Sensors
- Not interchangeable
- Operating Temperature Range
- 0° to +70°C
- Probe-to-Probe Variability
- ±0.5% VWC in dry soil, ±1.5% VWC in typical saturated soil
- Precision
- Better than 0.1% VWC
- Resolution
- 0.1% VWC
- Output
- ±0.7 V square wave
(with frequency dependent on water content)
- Current Drain
- 65 mA @ 12 Vdc
(when enabled)
- Current Drain
- 45 μA
(quiescent typical)
- Power Supply Voltage
- 5 Vdc minimum; 18 Vdc maximum
- Enable Voltage
- 4 Vdc minimum; 18 Vdc maximum
- Electromagnetic
- CE compliant
(Meets EN61326 requirements for protection against electrostatic discharge.)
- Rod Spacing
- 32 mm
(1.3 in.)
- Rod Diameter
- 3.2 mm
(0.13 in.)
- Rod Length
- 300 mm
(11.8 in.)
- Probe Head Dimensions
- 85 x 63 x 18 mm
(3.3 x 2.5 x 0.7 in.)
- Cable Weight
- 35 g per m
(0.38 oz per ft)
- Weight
- 280 g
(9.9 oz) without cable
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Documents
- Manual
CS616 and CS625 Water Content Reflectometers
January 2026
View Document - Brochure
CS616 Water Content Reflectometer
March 2026
View Document South Korea: Damage from Freezing Roads
View Document- Technical Paper
Soil-specific calibration procedure for volumetric water content sensors
January 2021
View Document - View all documents
Videos and Tutorials

Installing a Soil Moisture Reflectometer Sensor
June 30, 2025 (5:56)
Full procedure to bury a soil moisture reflectometer sensor
Watch
Seminario web Humedad de Suelo
February 9, 2021 (20:51)
Soil Moisture Content measurement webinar - Spanish
Watch
Webinaire sur l’humidité du sol
February 9, 2021 (18:24)
Soil Moisture Content measurement webinar - French version
Watch
Measuring Water in the Soil: A Webinar
January 21, 2021 (32:06)
Common theories for making measurements of soil water content
Watch