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Summary of Contents for Campbell 229
- Page 1 229 Heat Dissipation Matric Water Potential Sensor User Manual Issued 21.2.12 © Copyright 2006-2009 Campbell Scientific Inc. Printed under licence by Campbell Scientific Ltd. CSL 678...
- Page 3 Quotations for repairs can be given on request. It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment, in support of this policy a “Declaration of Hazardous Material and Decontamination”...
- Page 5 PLEASE READ FIRST About this manual Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the North American market. Some spellings, weights and measures may reflect this origin. Some useful conversion factors: Area: 1 in...
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Page 7: Table Of Contents
5.5 Example #1 — CR1000 with CE4 and Four 229s ........8 5.6 Example #2 — CR1000 with AM16/32-series Multiplexer, CE4 and Sixteen 229 Sensors with Temperature Correction ..... 10 5.7 Example #3 — CR10X with 229 Sensor ..........12 5.8 Example #4 —... - Page 8 Assembly ..................... 1 1-2. CE4 and CE8 Current Excitation Modules ..........2 1-3. Typical Temperature Response of 229 Sensor in Silt Loam Soil ... 3 4-1. Schematic of Connections for Measurement of a 229 Sensor ....5 6-1. Data Points and Regression for Typical Calibration ......19 6-2.
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Page 9: General Description
The volume inside the needle which is not occupied by wiring is filled with epoxy. Figure 1-1. A 229 Heat Dissipation Matric Water Potential Sensor is shown at the top. The hypodermic assembly (without epoxy and ceramic) is shown just below. Cutaway view shows longitudinal section of the needle with heater and thermocouple junction. -
Page 10: Compatibility
229 Heat Dissipation Matric Water Potential Sensor The –L option on the model 229 Heat Dissipation Matric Water Potential Sensor (229-L) indicates that the cable length is user specified. This manual refers to the sensor as the 229. Figure 1-2. CE4 and CE8 Current Excitation Modules 1.1 Compatibility... -
Page 11: Specifications
3.0ºC when dry. Figure 1-3 presents a typical temperature response in a silt loam. 200 kPa 100 kPa 50 kPa 10 kPa heating time (s) Figure 1-3. Typical Temperature Response of 229 Sensor in Silt Loam Soil 2. Specifications Measurement range: -10 to -2500 kPa Measurement time: 30 seconds typical... -
Page 12: Installation
50 mA ±0.25 mA per channel, regulated Output channels: CE4: 4 CE8: 8 Current drain(while active): 25 mA + 50 mA * no. of 229’s connected to the CE4 or CE8 output channels. Dimensions: CE4: 11.5 cm (4.5”) x 5.4 cm (2.1”) x 2.7 cm (1.1”) CE8: 16.5 cm (6.5”) x 5.4 cm (2.1”) x 2.7 cm (1.1”) -
Page 13: Example Programs
User Manual Table 4-1. 229 Sensor and CE4/CE8 Wiring CR10(X), CR23X, CR800, CR850, 229 Wire Function CR1000, CR3000 CE4/CE8 Colour Blue Thermocouple High High side of differential channel Thermocouple Low Low side of differential channel Green Heater High Current excitation channel... -
Page 14: Adjusting For Thermal Properties Of Sensor During Early Heating Times6
Since all of the output channels of the CE4 or CE8 are activated when the control terminal is set high, power will be applied to all of the 229 sensors connected to the current source. Inaccurate measurements can result if the temperature of multiple sensors is simply read sequentially. -
Page 15: Temperature Correction
The AM16/32B multiplexer in 4x16 mode provides a convenient method to measure up to sixteen 229 sensors. Since four lines are switched at once, both the thermocouple and the heating element leads for each sensor can be connected to a multiplexer channel. -
Page 16: Example #1 - Cr1000 With Ce4 And Four 229S
CR1000. 5.5 Example #1 — CR1000 with CE4 and Four 229s Table 5-1 shows wiring information for reading four 229 sensors with a CR1000 datalogger and CE4 current excitation module. Table 5-1. Wiring for Four 229s with CR1000 and CE4... - Page 17 'Set C1 low to deactivate CE4 For LoopCount=1 to Num229 'Calculate temperature rise DeltaT_C(LoopCount)=Temp_30sec_C(LoopCount)-Temp_1sec_C(LoopCount) 'LoopCount=LoopCount+1 Next LoopCount EndIf 'Ends Flag(1) true condition CallTable(Matric) 'Call Data Tables and Store Data Flag(1)=False 'Set Flag 1 false to disable 229 measurements NextScan EndProg...
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Page 18: Example #2 - Cr1000 With Am16/32-Series Multiplexer
5.6 Example #2 — CR1000 with AM16/32-series Multiplexer, CE4 and Sixteen 229 Sensors with Temperature Correction Table 5-2 shows wiring information for connecting multiple 229 sensors and CE4 excitation module to an AM16/32 multiplexer and CR1000 datalogger. See Figure 6-4 for a schematic of this wiring configuration. - Page 19 User Manual 'CR1000 SequentialMode Const Num229 = 16 'Enter number of 229 sensors to measure Const read229 = 60 'Enter Number of minutes between 229-L readings Const CalTemp = 20 'Enter calibration temperature (deg C) Dim i, dTdry(Num229), dTwet(Num229) Dim Tstar, Tstarcorr, DeltaTcorr, s...
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Page 20: Example #3 - Cr10X With 229 Sensor
5.7 Example #3 — CR10X with 229 Sensor Table 5-3 shows wiring information for reading a single sensor with a CR10X datalogger, CE4 current excitation module, and CR10XTCR thermocouple reference temperature sensor. Table 5-3. 229 Sensor and CE4/CE8 Wiring with CR10XTCR Function CR10(X) CR10XTCR... - Page 21 User Manual ;{CR10X} ;Program to read 1 229-L sensor ;Reading 1 sensor takes 30 seconds *Table 1 Program 01: 60 Execution Interval (seconds) 1: If time is (P92) 1: 0 Minutes (Seconds --) into a 2: 60 Interval (same units as above)
- Page 22 229 Heat Dissipation Matric Water Potential Sensor 8: Excitation with Delay (P22) ;Wait 29 more seconds for next reading 1: 1 Ex Channel 2: 0 Delay W/Ex (0.01 sec units) 3: 2900 Delay After Ex (0.01 sec units) 4: 0000...
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Page 23: Example #4 - Cr10X With Am16/32-Series, Ce4, And Sixteen 229 Sensors
5.8 Example #4 — CR10X with AM16/32-series, CE4, and Sixteen 229 Sensors Table 5-4 shows wiring information for connecting multiple 229 sensors and CE4 or CE8 excitation module to an AM16/32-series multiplexer and CR10X datalogger. A CR10XTCR or 107 probe should be used for the reference temperature measurement as described at the beginning of this section. - Page 24 229 Heat Dissipation Matric Water Potential Sensor ;{CR10X} ;Program to read 16 229-L sensors using 1 AM16/32 multiplexer ;and 1 CE4 or CE8 constant current interface ;Manually set Flag 1 high to force readings *Table 1 Program 01: 30 Execution Interval (seconds)
- Page 25 Do if Flag 1 is High 2: 10 Set Output Flag High (Flag 0) 20: Set Active Storage Area (P80) 1: 1 Final Storage Area 1 2: 229 Array ID 21: Real Time (P77) 1: 1220 Year,Day,Hour/Minute (midnight = 2400)
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Page 26: Calibration
6. Calibration 6.1 General The heat transfer properties of a 229 sensor depend both on the thermal properties of the various sensor materials and on the interfaces between the different materials. Heat transfer between the stainless steel needle containing the heating element and thermocouple and the ceramic material depends on the density of points-of-contact between two different materials. -
Page 27: Normalized Temperature Change And Correction For Soil Temperature
Δ − Δ norm Δ where is the change in temperature during measurement when the 229 Δ sensor is dry, is the change in temperature during measurement when the Δ 229 sensor is fully saturated and is the change in temperature during the Δ... -
Page 28: Correction For Soil Temperature
The 229 measurement method uses heat transfer away from a heated line source and the heat transfer depends on the thermal conductivity of the ceramic. The thermal conductivity of the ceramic depends on the combination of the conductivities of water, vapour and solid constituents. -
Page 29: Measurement Error For Range Of Soil Temperatures And Wide Range Of
User Manual 1000 1500 2000 matric potential (-kPa) 10 degrees C 16 degrees C 18 degrees C 22 degrees C 24 degrees C 30 degrees C Figure 6-2. Measurement error for range of soil temperatures and wide range of matric potential. -
Page 30: Measurement Error For Range Of Soil Temperatures And Wetter Range Of
229 Heat Dissipation Matric Water Potential Sensor matric potential (-kPa) 10 degrees C 16 degrees C 18 degrees C 22 degrees C 24 degrees C 30 degrees C Figure 6-3. Measurement error for range of soil temperatures and wetter range of matric potential. -
Page 31: Using Pressurized Extraction Methods
229 sensors are buried. Smaller rings can also be used. The porous plate, soil and 229 sensors must be thoroughly saturated at the beginning of the calibration routine. -
Page 32: Wiring For Calibration Using Pressure Plate Extractor
6.4.1 Wiring for Calibration using Pressure Plate Extractor The wiring arrangement of Figure 6-4 depicts a datalogger with an AM16/32 multiplexer, a CE4 current source and a thermistor being used in a typical 229 calibration arrangement. This is similar to the wiring for program example #2 and #4 (see Section 5). -
Page 33: Maintenance
User Manual 7. Maintenance The 229 does not require maintenance after it is installed in the soil. The datalogger, current excitation module, and multiplexer, if used, should be kept in a weatherproof enclosure. Periodic replacement of the desiccant in the enclosure is required to keep the electronics dry and free of corrosion. -
Page 34: References
229 Heat Dissipation Matric Water Potential Sensor 9. References Flint, A. L., G. S. Campbell, K. M. Ellett, and C. Calissendorff. 2002. Calibration and Temperature Correction of Heat Dissipation Matric Potential Sensors. Soil Sci. Soc. Am. J. 66:1439–1445. Reece, C.F. 1996. Evaluation of a line heat dissipation sensor for measuring soil... - Page 36 CAMPBELL SCIENTIFIC COMPANIES Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah 84321 UNITED STATES • www.campbellsci.com info@campbellsci.com Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA • www.csafrica.co.za sales@csafrica.co.za Campbell Scientific Australia Pty. Ltd. (CSA)
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