This product is no longer available.
| Services Available | |
|---|---|
| Repair | Yes |
| Calibration | No |
| Free Support | Yes |
Overview
The CS625 measures the volumetric water content from 0% to saturation. It is similar to our CS616 but is designed specifically for CR200(X) and CR300-series dataloggers. This reflectometer has a 0 to 3.3 V square wave frequency output that our CR300-series and CR200(X)-series dataloggers can measure.
Read MoreBenefits and Features
- High accuracy and high precision
- Fast response time
- Designed for long-term unattended water content monitoring
- Probe rods can be inserted from the surface or buried at any orientation to the surface.
Images
Detailed Description
The CS625 consists of two 30-cm-long stainless steel rods connected to a printed circuit board. The circuit board is encapsulated in epoxy, and a shielded four-conductor cable is connected to the circuit board to supply power, enable probe, and monitor the output.
The CS625 measures the volumetric water content of porous media (such as soil) using the time-domain measurement method; a reflectometer (cable tester) such as the TDR100 is not required. This method consists of the CS625 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 CS625 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 CS625 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 operating manual.
Specifications
| Measurements Made | Volumetric water content of porous media (such as soil) |
| 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 | 0.1% VWC |
| Resolution | 0.1% VWC |
| Output | 0 to 3.3 V square wave (with frequency dependent on water content) |
| Current Drain |
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| 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 |
Compatibility
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.
Data Loggers
| Product | Compatible | Note |
|---|---|---|
| CR1000 (retired) | ||
| CR200X (retired) | ||
| CR206X (retired) | ||
| CR211X (retired) | ||
| CR216X (retired) | ||
| CR295X (retired) | ||
| CR300 | ||
| CR3000 (retired) | ||
| CR310 | ||
| CR5000 (retired) | ||
| CR800 (retired) | ||
| CR850 (retired) | ||
| CR9000X (retired) |
Additional Compatibility Information
RF Considerations
The RF emissions are below FCC and EU limits as specified in EN61326 if the CS625 is enabled less than 0.6 ms, and measurements are made less frequently than once a second. External RF sources can also affect the CS625 operation. Consequently, the CS625 should be located away from significant sources of RF such as ac power lines and motors.
Installation Tool
The CS650G makes inserting soil-water sensors easier in dense or rocky soils. This tool can be hammered into the soil with force that might damage the sensor if the CS650G were not used. It makes pilot holes into which the rods of the sensors can then be inserted. It replaces both the 14383 and 14384.
Data Logger Considerations
Each CS625 requires a single-ended input channel. A control port is used to enable one or more probes.
Note: A maximum of four CS625 probes can be measured by one CR200(X) datalogger. Valid channel options are analog channels 1 through 4.
Documents
Frequently Asked Questions
Number of FAQs related to CS625: 34
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300 m (1,000 ft).
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Yes, as long as the data logger can detect a 0 to 3300 mV square wave over a frequency range of 29 to 67 kHz.
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The CS616 and CS625 are the same in size, form, and function. The only difference is in the output signal. The CS616 has a ±700 mV square wave output, whereas the CS625 has a 0 to 3300 mV square wave output.
The CS625 was designed for use with the CR200- and CR200X-series dataloggers, which cannot measure negative voltages. Consequently, the output was modified to keep the entire signal in the positive voltage range.
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Yes. The PeriodAvg() CRBasic instruction may be used to measure the CS625 on a CR1000, CR800-series, or CR3000 datalogger. To make this work, it is important that the Threshold parameter be set to 1650 mV as shown in the following example:
PortSet (1 ,1 ) ‘Enable CS625 by setting C1 high (orange wire to C1)
PeriodAvg (PA_uS,1,mV250,1,1650,0,100,10,1.0,0) ‘Read Period on SE1 (green wire to SE1)
PortSet (1 ,0) ‘Disable CS625 by setting C1 low
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Cutting down rods should only be done at the user’s own risk. Doing so will cause the probe to need recalibration. Campbell Scientific does not provide calibrations for shorter rod lengths for the CS616 or the CS625.
With shorter rods, the probe will work, but there will be some reduction in accuracy because the length of the rod in the soil contributes a smaller proportion to the total transit time. However, probes with shorter rods will work in more saline soils.
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If the electrical conductivity within the waste is less than 5 dS/m and there is good contact between the probe rods and the waste, the CS616/CS625 should respond predictably to changes in water content. The heterogeneous nature and changing bulk density of solid waste, however, make calibration difficult.
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Some customers have tried to use the CS616 or CS625 to measure the moisture content within a tree, but the calibration proved to be problematic. Campbell Scientific cannot provide any specific guidance for this application.
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The CS616/CS625 can measure volumetric water content over the entire range from completely dry to saturation. A soil-specific calibration will improve accuracy, especially in very dry soil.
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Yes. For program examples and guidance on using a multiplexer with one of these reflectometers, see the CS616 and CS625 instruction manual.
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As long as the period value in the saturated soil is less than 42 ms, “NAN” will not be displayed. Conditions that can cause the period value to be too high include high electrical conductivity, high clay content, and high organic matter content. Under those conditions, it may be possible to get good results by using the PeriodAvg() or P27 instruction with a soil-specific calibration equation.
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