PASCO Specialty & Mfg. PS-2163 User's Manual
Contents
1. Hardware Setup The following three steps can be performed in any order The mini DIN plug on the a Soil Water Potential Probe 1 Connect the mini DIN plug of the Soil Water Potential Probe cable to the front cable fits into the sensor box end of the Soil Moisture Sensor box in only one way 2 Connect the Soil Moisture Sensor to a PASPORT interface 3 If you will be using a computer connect the PASPORT interface to the com puter s USB port DataStudio Setup If you will be using the Soil Moisture Sensor with a computer install the latest version of DataStudio first Check the PASCO web site at www pasco com for information ormatio ea gt found a new sensor How would you like to use it a 4 1 When you connect the Soil Moisture Sensor to the computer through a PASPORT interface the PASPortal window will launch automatically if DataStudio is not already running PASPortal 2 Select Launch DataStudio in the PASPortal window Launch EZ SCREEN ipeieh Daehn prone ihe aA A Digits display for soil moisture VWC and Water Potential kPa will appear 3 Inthe Digits display select VWC Potting Soil to make it active and then E remove it using the delete X button in the toolbar K z ee Mo Data Potting Soll To view and change the sample rate click Setup Note that the best results are usu ally obtained with the sample rate left at the default setting of 10 Hz 10 measure2. ments per second Xplorer and Xplorer GLX Setup 4 Click to begin data collection If you will be using an Xplorer or Xplorer GLX in logging mode not connected to a computer connect the sensor to the Xplorer or Xplorer GLX and then press to begin data collection SPARK Setup e Ifthe SPARK Science Learning System is off press and hold the power button on the bottom to turn it on and then wait for it to boot up e Connect the sensor Touch Water Potential in the list that appears and then touch SHOW to open a default graph display or touch BUILD to select a partic ular display e g digits display and then touch Water Potential and the desired display icon and finally touch OK Touch the Start button to begin data collection gt Start button PASC Ci 9 Soil Moisture Sensor Specifications PS 2513 Specifications PS 2513 Calibration Sensor Range 10 to 50 kPa pF 2 to pF 3 71 The Soil Water Potential Probe does Accuracy 5 from 10 to 50 kPa 20 of reading from 50 to 500 kPa Resolution 1 kPa from 10 to 100 kPa 4 kPa from 100 to 500 kPa Power 25 mA at 2 to 5 V DC Operating Temperature 0 to 50 C Default Sample Rate 10 samples per second Technical Support For assistance with any PASCO product contact PASCO at Address PASCO scientific 10101 Foothills Blvd Roseville CA 95747 7100 Phone 916 786 3800 worldwide 800 772 8700 U S Fax
3. soil 3 Remove large objects from the soil and break up large clods so the soil can fit through a 5 mm mesh 4 Pack the soil into the calibration container at approximately the field bulk den sity 5 Insert the Soil Moisture Probe fully into the soil Connect the probe to the sensor and the sensor to the interface and use the sensor to make a measurement in millivolts mV Record the measurement 6 Use the volumetric soil sampler to collect a sample near the probe Place the soil sample into a drying container Measure and record the mass of the soil sample plus the drying container and then replace the lid on the drying container 7 Wet the calibration soil by adding 200 to 300 milliliters of water to the soil as evenly as possible Thoroughly mix the soil 8 Repeat steps 3 through 7 until the soil approaches saturation This generally yields five to seven calibration points 9 Remove the lids from the drying containters Dry the volumetric soil samples in a 105 C oven for 24 hours 10 Remove the soil drying containers from the oven and replace the lids Allow the containers to cool 11 Measure and record the mass of the dry soil plus the container without lid Calculations 1 Determine and record the volume of water by subtracting the dry soil mass from the wet pre dried soil mass Convert the mass difference into a volume based on the density of water 1 g cm 2 Calculate and record the volumetric
4. 5 1318 15 31 100 402 95 873 4 529 0 2958 6 1374 15 31 101 060 95 886 5 174 0 3379 Al WC data 0 36 poo Data 0 34 New X Remove v Accept es a Oe Gick Accept to enter changes 0 30 Definition 0 28 VWC 4 07 4 x 0 227 a T Statistical Special gt DEG RAD Properties l 0 24 x Sensor Vout 0 22 Experiment Constants Ni VWC Run 1 T018 0 16 Soda m Slope 4 07E 4 1 6E 5 0 12 b Y Intercept 0 227 0 016 i 0 997 B o oO r Mean Squared Error 6 80E 5 Root MSE 0 00825 o a 0 04 0 02 650 700 750 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350 1400 Sensor voltage mY Experiment Suggestions e Measure soil moisture over time e Evaluate soil moisure content for various species of plants to determine the opti mal level of soil moisture e Examine soil moisture content in a greenhouse to determine the amount of irriga tion Specifications PS 2163 Sensor Range 0 to 45 volumetric water content in soil Accuracy 4 Resolution 0 1 Power 3 mA at5 VDC Operating Temperature 40 to 60 C Default Sample Rate 10 samples per second PASC Ci Soil Moisture Sensor PASCO Soil Water Potential Probe PS 2513 PASCO Soil Water Potential Probe PS 2513 In the engineering community Introduction soil suction is used instead of soil water pote
5. that will appear on the screen Other If the type of soil or media that you are using does not appear in the Unit of Measure list you may want to make measurements to create a soil specific calibration curve yourself or take advantage of Decagon s calibration service Information on individuual probe calibration can be found online at www decagon com appnotes echocal pdf Information on Decagon s calibration service can be found at www decagon com echo calibration html Creating a Calibration Curve Volumetric Water Content VWC is the ratio of the volume of water per volume of bulk soil One way to create a soil specific calibration curve is to match the voltage output from the Soil Moisture Probe to VWC values for several soil samples with dif ferent degrees of dryness and then plot a graph of VWC versus probe output in milli volts mV The basic process is to collect a measured volume of bulk soil measure its mass mea sure the probe reading in mV for the bulk soil dry the soil to determine the amount of water that was in the soil and calculate the ratio of the volume of water to the volume of bulk soil Then create a graph of VWC versus probe voltage and determine the best fit for the graph If the graph is linear determine the slope and y intercept If the graph is quadratic determine the coefficients of each term A linear calibration curve would have a formula of y mx b where y is the VWC 7 is the slope x
6. water content by dividing the volume of water cm by the volume of the soil sample cm Analysis 1 Plot volumetric water content versus the sensor voltage output in mV Open a data table and enter the values for sensor voltage output x axis and volumetric water content y axis 2 Open a graph display and use the Fit function to find the best fit for the plot ted data Try Linear first and then Quadratic Record the slope and the y intercept If the best fit is quadratic record the coefficient a b and c 3 Create a calculation for VWC based on the slope and the y intercept VWC mx b Let x be the sensor voltage output Setup Any water loss due to evaporation after sampling introduces error to the volumetric water content calculation If the best fit is quadratic create a calculation for VWC based on the coefficients a b and c VWC ax bx c where x is the sensor voltage output PASC Cm Model No PS 2163 Setup Sample Calibration Data Sensor Sample Mass of Mass of Volume of VWC voltage volume cm container container water cm cm cm output mV moist soil g dry soil g 1 664 15 31 94 836 94 215 0 621 0 0406 2 164 15 31 96 433 95 194 1 239 0 0809 3 902 15 31 96 923 94 785 2 138 0 1396 4 1030 15 31 101 979 98 834 3 145 0 2054
7. 916 786 3292 Web Www pasco com Email support pasco com For more information about the Soil Moisture Sensor and the latest revision of this Instruction Manual visit www pasco com go PS 2163 Limited Warranty For a description of the product warranty see the PASCO catalog Copyright The PASCO scientific 012 10538A Soil Moisture Sensor Instruction Manual is copyrighted with all rights reserved Permission is granted to non profit educational institutions for reproduction of any part of this manual providing the reproductions are used only in their laboratories and classrooms and are not sold for profit Reproduction under any other circumstances without the written consent of PASCO sci entific is prohibited Trademarks PASCO PASCO scientific DataStudio PASPORT Xplorer and Xplorer GLX are trademarks or registered trademarks of PASCO scientific in the United States and or in other countries For more information visit www pasco com legal Windows is a registered trademark of Microsoft Corporation in the United States and or other countries Mac is a trademark of Apple Com puter Inc registered in the U S and other countries Product End of Life Disposal Instructions This electronic product is subject to disposal and recycling regulations that vary by country and region It is your responsibility to recycle your electronic equipment per your local environmental laws and regulations to ensure that it will be recycled in a manner t
8. a i Lad Sensor Vout mV EA H v VWC Water Potential 0 0 kPa Sensor Vout 502 mV Calibration Rockwool is a green fibrous mat The Soil Moisture Sensor comes pre calibrated for three soil types potting soil min visually similar to fiberglass insu eral soil and rockwool The Soil Moisture Probe is insensitive to variation in texture lation used to grow greenhouse crops in hydroponics 4 PASC Ce Model No PS 2163 and soil conductivity because it operates at a high frequency Therefore its calibra tions should apply for all potting soil mineral soil and rockwool Selecting Soil Type In DataStudio click Setup gt Setup to open the Experiment Setup window In the Patting Soil Experiment Setup window click the menu button under Unit of Measure and select amuki the soil type With the Xplorer press the check button _ to highlight the soil type then press the plus button to toggle through the soil selection choices Press the check but ton again to select your choice With the Xplorer GLX showing VWC in the digits display press the check button Q to open the selection menu for the display Use the right cursor arrow key b to open the soil type menu and then use the down cursor arrow key to select the soil type Press the check button again to select your choice With the SPARK SLS connect the Soil Moisture Sensor and select the soil type from the list of choices
9. an attenuate the probe s electromagnetic field and adversely affect output readings 3 cm TEIH Model No PS 2163 Setup Horizontal Orientation The probe can be oriented in any direction However orienting the flat side perpen dicular to the surface of the soil will minimize the effects of downward water move ment The horizontal orientation of the probe makes sure that the soil moisture measurement is made at a particular soil depth Do not bend the cable too severely when putting the probe into the soil Let about 10 cm of the cable nearest to the probe remain straight or gently curved as shown 10 cm 3cm Make a narrow trench with a trenching shovel or garden spade Place the probe into the narrow trench and completely cover the entire length with soil Tamp down the soil along both sides of the probe with your fingers Cover with more soil if needed Repeat the process of tamping down the soil along both sides of the probe five to eight times Removing the Soil Moisture Probe When removing the soil moisture probe from the soil do not pull it out of the soil by the cable Doing so may break internal components and make the probe unusable Setup Hardware Setup The following three steps can be performed in any order 1 Connect the mini DIN plug of the Soil Moisture Probe Cable Assembly to the The mini DIN plug on the Soil front end of the Soil Moisture Sensor box Moisture Cable As
10. hat protects human health and the environment To find out where you can drop off your waste equipment for recycling please contact your local waste recy cle disposal service or the place where you purchased the product The European Union WEEE Waste Electronic and Electrical Equipment symbol to the right and on the product or its packaging indicates that this product must not be disposed of in a standard waste container 10 not require any calibration by the user The probe s survival temper ature is from 40 to 50 C PASC Cm
11. he sensor reading Therefore any air gaps or excessive soil compaction around the probe can profoundly affect the readings Because the probe has a gap between its prongs it is also impor tant to consider the size of the media you are inserting the probe into It is possible to get sticks bark roots or other material stuck between the probe prongs which will adversely affect readings Finally be careful when inserting the probe into dense soil as the prongs will break if excessive sideways force is used when pushing them in When installing the probe it is best to maximize contact between the probe and the soil Vertical Orientation Insert the probe into the soil making sure that the probe is completely buried at least 3 cm below the soil surface The tip of each prong is sharp be careful The probe may be difficult to insert into extremely compact or dry soil Carefully loosen the soil before inserting the probe Never pound the probe into the soil Make sure that there is good contact between the probe and the soil Use your fingers and fist to tamp the soil down around the probe Introduction The copper traces used to measure water content are sealed between two pieces of epoxy impregnated fiberglass The electromagnetic EM field generated by the traces travels through the fiberglass and into the soil surrounding the probe Do not install the probe adjacent to large metal objects such as metal poles or stakes This c
12. hould be back filled with care taken to re pack the soil back to its native bulk density Leave at least 15 cm of cable beneath the soil Do not bend the cable in a tight radius as it leaves the probe At least 10 cm of cable nearest the probe should remain in a straight line Removing the Probe When removing the soil water potential probe from the soil do not pull it out of the soil by the cable Doing so may break internal components and make the probe unus able Handling and Care For the probe to accurately measure water potential the ceramic disks must readily take up water If the ceramic disks are exposed to oils or other hydrophobic sub stances then the ability of the disks to take up water can be compromised As much as possible minimize the exposure of the ceramic disks to skin oils synthetic oils or other hydrophopic compounds Frozen Soil Under frozen soil conditions the The probe consists of two engineered ceramic disks sandwiched between stainless probe cannot accurately mea steel screens and the probe s circuit board The disks are brittle and can chip or crack SUre the water potential of soil l However the probe is unaffected if mishandled Sharp trauma such as dropping the probe onto a hard surface can cause by repeated freeze thaw cycles the ceramic to break A cracked ceramic will cause a loss of accuracy so the probe can remain in the soil year round 8 PASC Cm Model No PS 2163 Setup Setup
13. is the probe output in mV and b is the y intercept Finally create a calculation based on the formula for the soil specific calibration curve Equipment shovel and bulk soil container calibration container Soil Moisture Probe and PASCO Interface volumetric soil sampler soil drying containers with lids e g baby food jars scale or mass balance drying oven Procedure 1 Collect approximately 4 liters of bulk soil from the depth location where you want to measure with the probe PASC Ce Mineral Soil Rockwool 4 44 04 AM 01 01 00 Setup Unit of Measure XplorerGlx oeoe Potting Soil Pottin gSoil v Mineral Soil Rockwool Sensor Vout i mv 506 The Soil Moisture Probe is built by Decagon Devices Inc 2365 NE Hopkins Ct Pullman WA 99163 See the User s Guides for the Xplorer GLX or the SPARK Science Learning System for calibration instructions A quadratic calibration curve would have a formula of y ax bx c where y is the VWC x is the probe output in mV and a b and c are coefficients 1 A volumetric soil sampler could be a 3 to 5 cm section of metal conduit or other small diameter 1 5 to 2 5 cm metal or thin walled plastic tubing Deburr both ends and sharpen one end for easy insertion into the soil Measure its dimensions and calculate the volume wh Soil Moisture Sensor 2 Air dry the soil spread the soil in a thin layer and use a fan to move air over the
14. mode not connected to a computer turn on the Xplorer GLX and connect the Soil Moisture Sensor A digits display of 509 Volumetric Water Content VWC Potting Soil and Sensor Voltage Output Sen sorVout mV will appear Press to begin data collection n m SPARK Setup gt a e Ifthe SPARK Science Learning System SLS is off press and hold the power Spar K ta button on the bottom to turn it on and then wait for the SPARK to boot up The TO BEIN l COLLECTING DATA screen will show a message to plug in a sensor PLUG IN A SENSOR e Connect the PASPORT sensor to either of the ports on the top of the SPARK The screen will show the list of quantities measured by the connected sensor Graph Display default To open a graph display touch any quantity in the list and then touch SHOW to open gt PAGE 1 Touch the right arrow next to PAGE to go to the next display digits Siar nition Touch the Start button to begin collecting data Select a Display To set up a particular display e g digits display touch BUILD Touch a quantity from the list and then touch one of the display icons Touch OK to open the display and then touch the Start button to begin collecting data Xe a Create your first page Soil Moisture 4 A Preview 18 3 Potting VWC Soil Soil Moisture 4 Lea VWC 19 6 Mineral VWC Potting Soil Le Soil 36 8 Rockwool WC Mineral Soil A 70 Toe VWC Rockwool Water Potential kP
15. ntial Soil water potential is simply the negative There are two basic parameters that describe the state of water in soil one is soil of soil suciion water content or the amount of water per unit of soil and the other is soil water potential or the energy state of the water in the soil Water potential is often preferred over water content because it shows how water will move in a soil or from the soil to the plant In an object comes into hydraulic contact with soil the water potential of the object will come into equilibrium with the soil water potential The Soil Water Potential Probe uses a solid matric equilibration technique to measure the water potential of the soil The probe has a static matrix a porous ceramic disk that is allowed to reach hydraulic equilibrium with the soil that is being measured The probe measures the dielectric permittivity of the ceramic disk to determine its water potential and thereby the water potential of the soil Installing the Probe Because it measures water potential the probe needs good hydraulic contact with the surrounding soil The preferred method for installing the probe is to take some native soil wet it and pack it in a ball around the entire probe making sure that the moist soil is in contact with all surfaces of the ceramic disk The probe and moist soil are then packed into the soil at the desired depth After the probe is installed the hole that was excavated to bury the probe s
16. olid material 35 air pockets and 10 water The maximum volu metric water content would therefore be 45 All the air spaces would be filled with water and the soil would be saturated About the Sensor The Soil Moisture Probe uses capacitance to measure the dielectric permittivity of the surrounding soil The volume of water in the total volume of soil most heavily influ ences the dielectric permittivity because the dielectric of water 80 is much greater than the other constituents of the soil mineral soil 4 organic matter 4 air 1 Thus when the amount of water changes in the soil the Soil Moisture Probe will measure a change in the capacitance from the change in the dielectric permittivity that can be directly correlated with a change in water content Circuitry inside the Soil Moisture Probe changes the capacitance measurement into a proportional millivolt output The Soil Moisture Probe averages the volumetric water content over the entire length of the probe with a zone of influence about 2 cm around the probe The zone of influ ence is with respect to the flat surface there is little or no sensitivity at the edges of the probe The electromagnetic field EM produced by the probe decreases with dis tance from the probe surface Installing the Soil Moisture Probe When selecting a site for installation of the probe it is important to remember that the soil adjacent to the probe s surface has the strongest influence on t
17. ry Instruction Manual pasforl 012 10646A PASPORT Soil Moisture Sensor PS 2163 PS 2513 Soil Water Potential Probe not included Included Equipment Part Number 1 PASPORT Soil Moisture Sensor PS 2163 2 Soil Moisture Probe Cable Assembly 5514 10696 Accessory Equipment See the PASCO Catalog for details PASPORT Soil Water Potential Probe not included PS 2513 Compatible PASPORT Interfaces See the PASCO Catalog for details Xplorer PS 2000 PowerLink PS 2001 Xplorer GLX PS 2002 SPARK Science Learning System PS 2008 SPARKIlink PS 2009 USB Link PS 2100 See the PASCO catalog or visit the PASCO web site at www pasco com for more information about the PS 2513 Soil Water Potential Probe f B To O 800 772 8700 www pasco com Soil Moisture Sensor Introduction The PASCO Model PS 2163 Soil Moisture Sensor works with a PASCO interface to collect soil moisture data The sensor consists of the Soil Moisture Sensor box and the the Soil Moisture Probe cable assembly The sensor measures volumetric water content VWC percentage of a soil sample Volumetric water content is the volume of soil water per unit of total volume In sim ple terms dry soil consists of solid material and air pockets A typical volumetric ratio would be 55 solid material and 45 air pockets As water enters the soil the air pockets begin to fill with water An example of 10 volumetric water content would be 55 s
18. sembly fits into the sensor box in only one way 2 Connect the Soil Moisture Sensor to a PASPORT interface 3 If you will be using a computer connect the PASPORT interface to the com puter s USB port DataStudio Setup If you will be using the Soil Moisture Sensor with a computer install the latest version of DataStudio first Check the PASCO web site at www pasco com for informa tion PASPortal gt wa found H Id you lik it 1 When you connect the Soil Moisture Sensor to the computer a lt I found a new sensor How would you like to use it through a PASPORT interface the PASPortal window will 7 launch automatically 1f DataStudio is not already running 2 Select Launch DataStudio in the PASPortal window SF i Launch EZ SCREEN Launch DataStudio Ignore The Sensor A Digits display for volumetric moisture content VWC will appear The default is for Potting Soil PASC Ce 3 Soil Moisture Sensor setup 3 Click to begin data collection SWVC No Data To view and change the sample rate click Note that the best results are usu ally obtained with the sample rate left at the default setting of 10 Hz 10 measure ments per second Xplorer Setup Turn on the Xplorer and connect the Soil Moisture Sensor The display will show VWC Potting S Press to begin data collection 5104 38AM 01 01 00 XplorerGix MOOH Xplorer GLX Setup 19 0 If you will be using an Xplorer GLX in logging
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