Campbell Scientific CS616 CS616 and CS625 Water Content Reflectometers
Campbell Scientific CS616 Manual
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- Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 1
INSTRUCTION MANUAL CS616 and CS625 Water Content Reflectometers Revision: 2/14 Copyright © 2002-2014 Campbell Scientific, Inc. - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 2
- Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 3
BY CAMPBELL SCIENTIFIC, INC. are warranted by Campbell Scientific, Inc. ("Campbell") to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless otherwise specified in the corresponding Campbell pricelist or product manual - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 4
problem, an RMA number will be issued. Please write this number clearly on the outside of the shipping container. Campbell Scientific's shipping address is: CAMPBELL SCIENTIFIC customer at the customer's expense. Campbell Scientific reserves the right to refuse service on products that were exposed - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 5
for CS616 16 6.4.5.1 CS616 Sample Edlog Program 1 16 6.4.5.2 CS616 Sample Edlog Program 2 17 6.4.5.3 CS616 Sample Edlog Program 3 18 6.4.5.4 CS616 Sample Edlog Program 4 19 6.4.5.5 CS616 Sample Edlog Program 5 21 7. The Water Content Reflectometer Method for Measuring Volumetric Water Content - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 6
Calculations 38 9. Maintenance 39 10. References 39 Appendix A. Discussion of Soil Water Content A-1 Figures 6-1. 6-2. 7-1. 7-2. 7-3. 7-4. CS616 Water Content Reflectometer 5 CS625 Water Content Reflectometer 5 CS616 and CS625 linear and quadratic calibrations derived from loam soil 25 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 7
and CS625 Water Content Reflectometers 1. Introduction The CS616 Water Content Reflectometer is an improved version of the CS615 Water Content Reflectometer. The CS625 is a modified CS616 for use with the Campbell Scientific CR200(X) series dataloggers. The difference between the CS616 and the - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 8
CS616 and CS625 Water Content Reflectometers The CS625 output is a square wave output and can be connected to Campbell Scientific CR200(X) series dataloggers. A CRBasic program using Period Averaging is used to measure the probe output period and convert to volumetric water content using - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 9
CS616 and CS625 Water Content Reflectometers CS625 Compatibility Dataloggers: CR200X series CR200 series Probe-to-Probe Variability: ±0.5% VWC in dry soil, ±1.5% VWC in typical saturated soil Resolution: better than 0.1% volumetric water content Water Content Accuracy: ±2.5% VWC using - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 10
and CS625 by taking repeated measurements in the same material. The precision of the CS616/CS625 is better than 0.1 % volumetric water content. Soil Properties The water content reflectometer operation can be affected when the signal applied to the probe rods is attenuated. The probe will provide - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 11
and the clear shield wire must be connected to datalogger ground. power Red output gnd Black output Green enable Orange drain/power gnd Clear FIGURE 6-1. CS616 Water Content Reflectometer power Red gnd Black output Green enable Orange drain/gnd Clear FIGURE 6-2. CS625 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 12
used by the CR800, CR850, CR1000 CR3000, and CR5000 dataloggers to measure the CS616 output period (in microseconds). The CS616() instruction is used to enable and measure a CS616 Water Content Reflectometer. CS616(Dest, Reps, SEChan, Port, MeasPerPort, Mult, Offset) Dest: The Dest parameter is the - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 13
CS625 Water Content Reflectometers Code 1 2 3 4 5 6 7 8 Description Control Port 1 Control Port 2 Control Port 3 Control Port 4 Control Port 5 Control Port 6 Control Port 7 Control Port 8 MeasPerPort: The MeasPerPort parameter is the number of control ports to be used to control the CS616 sensor - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 14
and CS625 Water Content Reflectometers CR1000 Program Example 1 'Declare Public and Dim Variables Public batt_volt Public Panel_temp Public Period (8) Public VWC (8) Public Flag (1) Dim I 'Declare Constants 'CS616 Default Calibration Constants const a0= -0.0663 const a1= -0.0063 const a2= 0.0007 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 15
and CS625 Water Content Reflectometers 6.4.1.2 CS616 Sample CRBasic Program 2 The following CR1000 program uses the AM16/32-series multiplexer to measure 48 CS616 probes connected in the 4x16 configuration. The program also measures datalogger battery voltage and temperature. Wiring for CRBasic - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 16
CS616 and CS625 Water Content Reflectometers 'Main Program BeginProg Scan (5,Sec,0,0) 'scan instructions every 5 sec Battery (Batt_volt) PanelTemp (Panel_temp,250) ' 'Set flag 1 High every 30 min (Note: User can manually set flag 1 high/low) If IfTime (0,30,min) Then flag (1) = high If - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 17
CS616 and CS625 Water Content Reflectometers Timeout: The Timeout parameter is the maximum time parameter is the control port or analog channel that will be used to switch power to the CS625 Water Content Reflectometer. Valid options are: Code 0 C1 C2 3 4 5 P_SW Description None Control Port 1 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 18
CS616 and CS625 Water Content Reflectometers 'CR200(X) program to read 4 CS625s 'Standard calibration is used to convert CS625 output 'period to volumetric water content. 'Sensors are read hourly and average water content are written to storage every 4 hours. 'Declare Variables Public period(4),vwc - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 19
+ a2*corrected^2 CallTable ofile NextScan EndProg 6.4.4 Measuring CS616 Using Edlog 6.4.4.1 Using Edlog Instruction 138 See Section 6.4.5.1, CS616 Sample Edlog Program 1, for example on using Instruction 138. 1: CS616 Water Content Reflectometer (P138) 1: 1 Reps 2: 00 SE Channel 3: 00 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 20
CS625 Water Content Reflectometers SE Chan: Enter the single-ended analog channel where the sensor's green wire is connected. When Reps is greater than 1, this entry is the channel for the first CS616. Port: Enter an integer to specify the control port that will be used to enable the CS616 sensor - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 21
CS616 and CS625 Water Content Reflectometers Reps: Enter the number of CS616s that will be measured with the instruction. The sensors must be wired in consecutive channels. Each measurement uses the same multiplier and offset. Range Option: Enter 2-digit integer to choose output as - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 22
CS616 and CS625 Water Content Reflectometers 6.4.5 Sample Edlog Programs for CS616 TABLE 6-3. CS616 Sample Edlog Programs Sample Program Number 1 2 3 4 5 Program Description Set Flag 1 to read output of one CS616 using CR10X instruction 138 and convert output period to volumetric water content - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 23
CS616 and CS625 Water Content Reflectometers 3: Polynomial (P55) 1: 1 Reps 2: 1 X Loc [ period 3: 2 CS616 Sample Edlog Program 2 Every 5 minutes, measure CS616 output period using instruction 27 and convert to volumetric water content. Write hourly average to datalogger final storage. CS616 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 24
CS616 and CS625 Water Content Reflectometers 3: Polynomial (P55) 1: 1 Reps 2: 1 X Loc [ period 3: 2 F(X) Loc [ vwc 4: -0.0663 C0 5: -0.0063 C1 6: 0.0007 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5 ] ] 4: Do (P86) 1: 51 Set Port 1 Low ;Turn Off CS616 probe 5: If time is (P92) ;Turn On Data - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 25
;{CR10X} ; *Table 1 Program 01: 3600 Execution Interval (seconds) 1: Batt Voltage (P10) 1: 7 Loc [ batt ] 2: CS616 Water Content Reflectometer (P138) 1: 3 Reps 2: 1 SE Channel 3: 6 C6 is first of sequential Control Ports used 4: 1 Loc [ period_1 ] 5: 1.0 Mult 6: 0.0 Offset - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 26
0.0 Offset ;Measure soil temperature. 4: CS616 Water Content Reflectometer (P138) 1: 1 Reps 2: 2 SE Channel 3: 4 C4 is first of sequential Control Ports used 4: 3 Loc [ CS616 ] 5: 1.0 Mult 6: 0.0 Offset ;The following four instructions correct CS616 period for soil temperature ;The - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 27
CS616 and CS625 Water Content Reflectometers 7: Z=X*Y (P36) 1: 5 2: 4 3: 4 X Loc [ TFactor ] Y Loc [ TempCS616 ] Z Loc [ TempCS616 ] 8: Z=X+Y (P33) 1: 3 2: 4 3: 6 X Loc [ CS616 ] Y Loc [ TempCS616 ] Z Loc [ NewCS616 ] 9: Polynomial (P55) ;Convert corrected probe period to water content. - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 28
and CS625 Water Content Reflectometers Sensor lead CS616-1 green CS616-2 green CS616-3 green CS616-1,2,3 orange CS616-4 green CS616-5 green CS616-6 green CS616-4,5,6 orange ... CS616-46 green CS616-47 green CS616-48 green CS616-46,47,48 AM16/32 1H 1L 2H 2L 3H 3L 4H 4L ... 31H 31L 32H 32L RES CLK - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 29
port 2 (i.e. Multiplier Clock) 9: CS616 Water Content Reflectometer (P138) ;Measure Period on 3ea CS616 1: 3 Reps 2: 1 SE instruction 13: Do (P86) 1: 51 ;Set control port 1 "low" (i.e. Multiplexer Reset) Set Port 1 Low 14: Polynomial (P55) ;Convert 48ea Period measurements into water content - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 30
CS616 and CS625 Water Content Reflectometers 53 VWC_2 . . 99 VWC_48 9 1 1 17 1 1 7. The Water Content Reflectometer Method for Measuring Volumetric Water Content 7.1 Description of Measurement Method The water content reflectometer method for measuring soil water content is an indirect - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 31
Volumetric Water Content (fractional) CS616 and CS625 Water Content Reflectometers 0.4 0.3 0.2 0.1 0 16 18 20 22 24 26 28 30 32 Output period (microseconds) calibration data linear fit quadratic fit FIGURE 7-1. CS616 and CS625 linear and quadratic calibrations derived from loam - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 32
and CS625 Water Content Reflectometers FIGURE 7-2 compares the CS616/CS625 response in the FIGURE 7-1 loam soil to a higher density sandy clay loam for two different electrical conductivities. The bulk density for both sandy clay - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 33
CS616 and CS625 Water Content Reflectometers 7.3 Calibration Equations TABLE 7-1 lists the calibration coefficients derived in the Campbell Scientific soils laboratory. Both linear and quadratic forms are presented. The choice of linear or quadratic forms depends on the expected range of water - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 34
CS616 and CS625 Water Content Reflectometers FIGURE 7-3. Difference in % volumetric water content between linear and quadratic forms of calibrations The linear and quadratic coefficients for the sandy clay loam data in FIGURE 7-3 follow and can be used - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 35
CS616 and CS625 Water Content Reflectometers 7.4 Operating Range 7.4.1 Soil Electrical Conductivity The quality of soil water measurements which apply electromagnetic fields to wave guides is affected by soil electrical conductivity. The propagation of electromagnetic fields in the configuration of - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 36
lower water content than actual. In some applications, installation can be improved by using insertion guides or a pilot tool. Campbell Scientific offers the CS650G insertion tool. 7.5.3 Signal Attenuation Error Section 7.1, Description of Measurement Method, presents a detailed description of CS616 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 37
and CS625 Water Content Reflectometers if there are free ions in soil solution, polar solid constituents such as organic matter or some clay, or conductive mineral constituents. The general calibration equation for the CS616/CS625 will provide good results with attenuation equivalent to about 0.5 dS - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 38
CS616 and CS625 Water Content Reflectometers Water Content Error with Temperature 8 6 Water Content Error (%VWC) 4 2 0 2 4 10 15 20 25 30 35 40 Soil Temperature (C) Water Content = 30% Water Content = 12% FIGURE 7-4. Percent volumetric water content error corrected for by - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 39
CS616 and CS625 Water Content Reflectometers Some clays are very polar and/or conductive and will also attenuate the applied signal. Additionally, if the clayey soil is compacted, increased bulk density, the conductivity is increased and the response is affected. Given the water content - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 40
Collecting Laboratory Data for Calibration Water content reflectometer data needed for CS616/CS625 calibration are the CS616/CS625 output period (microseconds) and an independently determined volumetric water content. From this data, the probe response to changing water content can be described by - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 41
CS616 and CS625 Water Content Reflectometers The typically used method for packing a container of soil to If subsampling is used, remove soil from column and remix with samples used for water content measurement. Repack column. Water can then be added to the top of the container. It must be allowed - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 42
CS616 and CS625 Water Content Reflectometers Method D4643-93 requires heating in microwave for 3 minutes, cooling in desiccator then weighing and repeating this process until weigh is constant. Gravimetric water content is calculated after the container weight is accounted for. θg = mwet − mdry - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 43
and CS625 Water Content Reflectometers with θv , the volumetric water content (m3 m-3); τ, the CS616/CS625 period (microseconds); Co , the intercept; and C1 , the slope. The calibration coefficients are derived from a curve fit of known water content and CS616/CS625 period. The number of data sets - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 44
CS616 and CS625 Water Content Reflectometers Gravimetric water content is calculated after the container weight is accounted for. θg = mwet − mdry mdry For the bulk density, ρbulk = mdry volumecylinder the dry weight of the sample is divided by the sample tube volume. The volumetric water - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 45
and CS625 Water Content Reflectometers To obtain soil bulk density, use ρbulk = mdry volumecylinder Volumetric water content is calculated using θv = θg *ρbulk . 9. Maintenance The CS616/CS625 does not require periodic maintenance. 10. References Rhoades, J.D., P.A.C. Raats, and R.J. Prather - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 46
CS616 and CS625 Water Content Reflectometers 40 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 47
Appendix A. Discussion of Soil Water Content The water content reflectometer measures volumetric water content. Soil water content is expressed on a gravimetric and a volumetric basis. To obtain the independently determined volumetric water content, gravimetric water content must first be measured. - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 48
Appendix A. Discussion of Soil Water Content A-2 - Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 49
- Campbell Scientific CS616 | CS616 and CS625 Water Content Reflectometers - Page 50
Centro Caribe S.A. (CSCC) 300 N Cementerio, Edificio Breller Santo Domingo, Heredia 40305 COSTA RICA www.campbellsci.cc • [email protected] Campbell Scientific Ltd. (CSL) Campbell Park 80 Hathern Road Shepshed, Loughborough LE12 9GX UNITED KINGDOM www.campbellsci.co.uk • [email protected]
INSTRUCTION MANUAL
CS616 and CS625
Water Content Reflectometers
Revision: 2/14
Copyright © 2002-2014
Campbell Scientific, Inc.