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EIJKELKAMP SM150-UM-1, User Manual

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EIJKELKAMP SM150-UM-1 User Manual Download Page 22

 

SM150 User Manual 1 

Operation  

 

  

22 

Linearisation table

  

(for use over the full range of SM150 readings)

 

V

 



 

V

 



 

V

 



 

V

 



 

V

 



 

0.000 

1.000 

0.300 

3.576 

0.600 

5.101 

0.900 

6.778 

1.200 

8.924 

0.075 

1.942 

0.375 

3.964 

0.675 

5.503 

0.975 

7.232 

1.275 

9.743 

0.150 

2.620 

0.450 

4.337 

0.750 

5.917 

1.050 

7.720 

1.350  10.808 

0.225 

3.144 

0.525 

4.713 

0.825 

6.342 

1.125 

8.270 

1.425  12.242 

 

Soil moisture reading 

Polynomial conversion 

Combining the 

Soil calibrations

 and 

Sensor calibration

 

steps, the conversion equation becomes: 

     

[                         

 

          

 

          

 

          

 

]    

 

 

 

 

where 

a

0

 and 

a

1

 

are the calibration coefficients 

For a generalised 

mineral

 soil this becomes: 

 

 

       

                             

 

         

 

         

 

         

 

 

And for a generalised 

organic

 soil: 

 

       

                             

 

         

 

         

 

         

 

 

 

 

Summary of Contents for SM150-UM-1

Page 1: ...ual for the SM150 Soil Moisture Sensor SM150 UM 1 P O Box 4 6987 ZG Giesbeek Nijverheidsstraat 30 6987 EM Giesbeek The Netherlands T 31 313 880200 F 31 313 880299 E info eijkelkamp com I http www eijkelkamp com ...

Page 2: ...7944220 Europe Patent EP1836483 Australia Patent AU2005315407 China Patent Application CN101080631 EMC Compliance See page 31 Design changes Delta T Devices Ltd reserves the right to change the designs and specifications of its products at any time without prior notice User Manual Version SM150 UM 1 Nov 2011 P O Box 4 6987 ZG Giesbeek Nijverheidsstraat 30 6987 EM Giesbeek The Netherlands T 31 313 ...

Page 3: ...orks 9 Operation 10 Cable Connections 10 Installation 11 HH150 Meter 12 HH2 Meter 13 Logger connections and configuration 14 GP1 Logger 14 DL6 Logger 15 DL2e Logger 16 Other data loggers 17 Calibration 18 Soil calibration 19 Sensor calibration 21 Soil moisture reading 22 Troubleshooting 24 Technical Reference 26 Specifications 26 Definitions 32 ...

Page 4: ...50 User Manual 1 Introduction 4 References 34 Appendix 1 35 Soil specific Calibration 35 Laboratory calibration for non clay soils 36 Laboratory calibration for clay soils 39 Technical Support 42 Index 44 ...

Page 5: ...moisture by a data logger or meter using the supplied general soil calibrations It can also be calibrated for specific soils Features Soil moisture accurate to 3 Low salinity sensitivity Excellent stability Minimal soil disturbance Easy installation at depth in augured holes Waterproof connector to IP68 Rugged weather proof and can be buried Good electrical immunity Choice of cabling system option...

Page 6: ...SM150 User Manual 1 Introduction 6 67 mm 92 mm 51mm 22mm 12 40 mm Dimensions Cable connector sealed to IP68 M12 5 pin male Thread inch BSP for connecting to Extension Tube s ...

Page 7: ...ML EX100 100cm SM AUG 100 Spiral Auger 1 2m Logger extension cables Extension tubes HH150 SM150 Kit SMCS d HH2 1 5m cable Connects SM150 to HH2 SMSC sw 05 5m cable 100mm flying leads Connect to GP1 DL6 loggers SMSC lw 05 5m cable 200mm flying leads Connect to DL2 data logger HH150 includes 1m cable Connects to SM150 HH150 soil moisture sensor ...

Page 8: ...ts protective tube when not in use Take care when attaching cables to ensure that the connectors are clean undamaged and properly aligned before pushing the parts together Do not pull the SM150 out of the soil by its cable If you feel strong resistance when inserting the SM150 into soil it is likely you have encountered a stone Stop pushing and re insert at a new location Do not touch the pins par...

Page 9: ...e soil The water content of the soil surrounding the rods dominates its permittivity A measure of a material s response to polarisation in an electromagnetic field Water has a permittivity 81 compared to soil 4 and air 1 The permittivity of the soil has a strong influence on the applied field Vout which is detected by the SM150 resulting in a stable voltage output that Soil Moisture 22 acts as a s...

Page 10: ...before pushing the parts together Screw together firmly to ensure the connection is water tight Extension cables can be joined up to a recommended maximum of 100m for GP1 DL6 or DL2e data loggers see Specifications on page 26 Note for full accuracy do not use extension cables with the HH150 EXT 5W 05 5m EXT 5W 10 10m EXT 5W 25 25m Logger extension cables SMCS d HH2 1 5m cable Connects SM150 to HH2...

Page 11: ...ure good soil contact If you feel strong resistance when inserting the SM150 you have probably hit a stone Stop and re insert at a new location Installing at depth Make a 45mm diameter hole preferably at about 10 to the vertical using the SM AUG 100 auger Connect an extension tube e g ML EX50 Push the SM150 into the soil until rods are fully inserted Ensure good soil contact Alternatively Dig a tr...

Page 12: ... water content of Mineral or Organic soils or to show the sensor output in Volts Press off to save the current Setting and turn the meter off With the meter off press the left on read button to take a reading Repeat as required You may wish to write down the readings Turn on take and display reading Turn on show current setting OFF Organic 32 2 vol Read Organic Organic 34 3 vol Mineral Volts OFF R...

Page 13: ...creen press Set and scroll down to the Soil Type option Press Set again and scroll down to the appropriate soil type use Mineral for sand silt or clay soils or Organic for peaty soils Press Set to confirm this choice Choose the units you want for displaying readings At the start up screen press Set and scroll down to the Display option Press Set again and scroll down to select units Press Set to c...

Page 14: ...e CH1 2 Signal LO black CH1 2 Cable shield green CH1 2 GND Not used grey Not connected Channel 3 and 4 wiring SM150 wire Colour GP1 terminal Power 0V brown CH1 2 GND or WET GND Power V white CH1 2 PWR or WET PWR Signal HI blue Temp3 4 IN Signal LO black Temp3 4 GND Cable shield green Temp3 4 GND or WET GND Not used grey Not connected In the DeltaLINK sensor menu configure each sensor type SM150 No...

Page 15: ...r DL6 terminal Power 0V brown 0V Power V white V Signal HI blue IN Signal LO black IN Cable shield green Not used grey Not connected In DeltaLINK 1 configure channel 6 as type SM150 See also the DL6 Quick Start Guide and the DeltaLINK online Help 1 You need the PC logger software DeltaLINK version 2 6 or later obtainable online at www delta t co uk or from the Software and manuals CD Issue 5 ...

Page 16: ...ack CH58 Cable shield green CH61 or 62 Not used grey Not connected Note If using channel 58 ensure the LAC1 card ribbon is attached to the connector block opposite terminal groups 46 60 See page 3 of DL2e Quick Start Guide Configure the chosen DL2e logger channels by selecting the appropriate S1M and S1O sensor types for mineral and organic soils listed in the Ls2Win 2 sensor library See also the ...

Page 17: ...il moisture units by using either Polynomial conversion on page 22 or Linearisation table conversion on page 23 Note Output signals in the range 0 to 1 0 volts from the SM150 corresponding to 0 to 60 water content in mineral soils see Linearisation table conversion on page 23 Note The SM150 has been optimised for warm up of 0 5 to 1 second duration It is recommended that the sensor is not powered ...

Page 18: ...th Delta T loggers and moisture meters This section explains how these calibrations work how to adapt them for other soils and how to provide calibrations for other data loggers The SM150 measures volumetric soil moisture by detecting the dielectric properties of the damp soil the permittivity or more conveniently the refractive index which is closely equivalent to The SM150 response is best under...

Page 19: ...e index measured by the SM150 is only affected by changes to the water content This relationship simplifies to 1 0 a a where the coefficients a0 and a1 conveniently parameterise the dielectric properties of soils Note that soil dry a _ 0 is usually between 1 3 to 2 3 a1 corresponds approximately to 1 water and usually takes a value about 8 0 Real soil values for a0 and a1 can vary significantly fr...

Page 20: ...nstead of adopting these general calibrations you may wish to determine specific calibration values of a0 and a1 for your soil This procedure is fairly straightforward if you can get access to standard laboratory equipment and is described in detail in Appendix 1 on page 35 Soil specific calibration can significantly improve the accuracy of individual readings but make less of an improvement to re...

Page 21: ...ctric performance This response can be approximated either by a polynomial below or by a linearisation table see next page Polynomial for use over the full range of SM300 readings where V is the SM150 output in Volts 0 0 2 0 4 0 6 0 8 0 0 00 0 20 0 40 0 60 0 80 1 00 1 20 ε SM150 output V SM150 dielectric performance ...

Page 22: ...975 7 232 1 275 9 743 0 150 2 620 0 450 4 337 0 750 5 917 1 050 7 720 1 350 10 808 0 225 3 144 0 525 4 713 0 825 6 342 1 125 8 270 1 425 12 242 Soil moisture reading Polynomial conversion Combining the Soil calibrations and Sensor calibration steps the conversion equation becomes where a0 and a1 are the calibration coefficients For a generalised mineral soil this becomes And for a generalised orga...

Page 23: ...l moisture Mineral soil Organic soil vol Volts Volts vol Volts Volts 4 2 090 2 090 52 0 758 0 638 0 0 046 0 022 56 0 818 0 695 4 0 076 0 046 60 0 876 0 750 8 0 110 0 074 64 0 933 0 805 12 0 149 0 105 68 0 987 0 859 16 0 195 0 140 72 1 039 0 910 20 0 248 0 180 76 1 087 0 962 24 0 308 0 226 80 1 130 1 010 28 0 373 0 279 84 1 170 1 056 32 0 440 0 336 88 1 206 1 099 36 0 507 0 397 92 1 238 1 138 40 0 ...

Page 24: ...oftware HH2Read version 2 6 or later are recommended GP1 DL6 Loggers DeltaLINK version 2 6 or later is required DL2e Logger Ls2Win 1 0 SR8 or later is required Consult the user manuals or the on line help for these devices and their related software Try alternative types of equipment if you have them available Check that you are using an appropriate soil calibration and the correct conversion meth...

Page 25: ...ally read about 1 5 volts in tap water because the salinity is typically 50mS m 1 The water reading you get will depend on the salinity of your local water Note HH150 meter indicates TOO WET above 1 5V or 85 vol Graph showing the effect of salinity on SM150 sensor output when fully immersed in water with no soil present 0 00 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90 00 100 00 0 0 0 2 0 4 ...

Page 26: ...ee page 29 Output signal 0 1 V differential 0 to 60 nominal Output compatible with HH150 HH2 GP1 DL6 DL2e Maximum cable length 1m HH150 meter 100m GP1 DL6 and DL2e data loggers Power requirement 5 14VDC 18mA for 1s Operating range 20 to 60 C Environment IP68 4 Sample volume 55 x 70mm diameter Dimensions Weight 143 x 40 mm diameter 0 1 kg 3 In water no soil present the reading may not be 100 vol It...

Page 27: ...800 1200 1400 non saline slightly saline moderately saline strongly saline extremely saline mS m 1 0 2 4 6 8 10 12 14 16 dS m 1 Classification of salinity 0 0 0 2 0 4 0 6 0 8 1 0 1 2 1 4 1 6 1 8 0 100 200 300 400 500 600 SM150 output V Conductivity ECp mS m 1 SM150 conductivity response at different watercontents 100 water 60 45 38 30 20 Typical soil conditions Typical artificial substrate conditi...

Page 28: ... a much lower refractive index than free water The percentage of bound water decreases with temperature and this produces a positive temperature response particularly in clay soils at lower water contents The last two effects partially offset each other but in soil conditions where one or the other effect dominates the SM150 will appear to have a significant temperature response This illustration ...

Page 29: ... accuracy requires a soil volume of one litre but the additional error from taking a reading in a 0 5 litre sample is negligible SM150s may interact if they are placed too close together they should be separated by at least 100mm 15 5 5 15 0 0 01 0 02 0 03 0 04 0 05 0 06 0 07 0 08 25 20 15 10 5 0 5 10 15 20 25 Distanceparallelto planeof rods fromacentreline between therods mm SM150 fieldof sensiti...

Page 30: ...SM150 is inserted too close to the wall of a plant pot the sensing field can see outside the pot This behaviour is shown in the graph below For best results keep a gap of at least 25mm 1 inch between the body of the sensor and the wall of the plant pot ...

Page 31: ...e 5 Regulatory information Europe This device conforms to the essential requirements of the EMC directive 2004 108 EC based on the following test standards EN61326 1 2006 Electrical requirement for measurement control and laboratory use EMC requirements Group 1 Class A equipment emissions section only EN61326 1 2006 Electrical requirement for measurement control and laboratory use EMC requirements...

Page 32: ...om approx 0 02 m 3 m 3 for sandy soils at the permanent wilting point through approx 0 4 m 3 m 3 for clay soils at their field capacity up to values as high as 0 85 m 3 m 3 in saturated peat soils Gravimetric Soil Moisture Content is defined as where is the mass of water in the sample and is the total mass of the dry sample To convert from volumetric to gravimetric water content use the equation w...

Page 33: ...ic content Salinity The preferred SI units for ionic conductivity are mS m 1 where S is Siemens the unit of electric conductance Dimensionally it is equivalent to the inverse of resistance i e Ohm 1 The following conversions apply 1 mS m 1 0 01 dS m 1 0 01 mS cm 1 10 µS cm 1 Soil salinity can be classified using the following descriptive categories See also http www land vic gov au DPI Vro vrosite...

Page 34: ...C 1994 Comments on Considerations on the use of time domain reflectometry TDR for measuring soil water content by W R Whalley Journal of Soil Sci 45 503 508 5 Roth C H M A Malicki and R Plagge 1992 Empirical evaluation of the relationship between soil dielectric constant and volumetric water content as the basis for calibrating soil moisture measurements Journal of Soil Sci 43 1 13 6 Knight J H 19...

Page 35: ...soils Laboratory calibration for clay soils We use the term substrate to refer to any artificial growing medium Underlying principle Soil moisture content is proportional to the refractive index of the soil as measured by the SM150 see Calibration section The goal of calibration is to generate two coefficients a0 a1 which can be used in a linear equation to convert probe readings into soil moistur...

Page 36: ...he soil or substrate This sample needs to be unchanged from its in situ density to be 0 5 litre to have the correct dimensions to fit the beaker and to be generally uniform in water content For cohesive soils this is most easily done with a soil corer Sandy soils can be poured into the beaker but you should take the subsequent measurements immediately as the water will quickly begin to drain to th...

Page 37: ...r organic soils and composts it s usual to air dry the sample to avoid burning off any volatile factions Weigh the dry sample in the beaker W0 627 2g Re insert the SM150 into the dry sample and record this reading V0 0 051V Calculate a0 For the SM150 In the dry soil V V0 0 051 Volts Substitute this into the equation gives Since 0 0 this is the value needed for a0 a0 1 66 Calculate w The water cont...

Page 38: ...ing gives 79 3 w Finally 51 8 0 25 0 66 1 79 3 0 0 1 w w a a1 8 51 Result a0 1 66 a1 8 51 In this example this soil is now calibrated You can now use these two numbers in place of the standard mineral or organic calibration factors to convert SM150 readings into volumetric water content θ using 1 0 a a See also page Underlying principle on page 35 ...

Page 39: ...er Soil corer Heat resistant beaker 500ml Weighing balance accurate to 1g Temperature controlled oven Process Notes and example Collect a wet sample of the clay soil 25 to 30 water content would be ideal This sample needs to be unchanged from its in situ density to be 500ml to have the correct dimensions to fit the beaker and to be generally uniform in water content This is most easily done with s...

Page 40: ...ake care not to over dry in places and allow time for the water content to equilibrate throughout the sample before taking a reading Reweigh Wm 693 2g Re measure with the SM150 Vm 0 180V Dry the sample thoroughly With clay soils this is usually achieved by keeping it in the oven at 105 C for several hours or days the time required depends on the sample size and porosity Weigh the dry sample in the...

Page 41: ...s for For the moist soil Substituting Vm 0 180 gives for Calculate a1 Then a1 9 00 Calculate a0 and a0 1 58 Result a1 9 00 a0 1 58 In this example this soil is now calibrated You can now use these two numbers in place of the standard mineral or organic calibration factors to convert SM150 readings into volumetric water content θ using 1 0 a a See also page Underlying principle on page 35 ...

Page 42: ...goods free of charge at Delta T s premises in the UK during the warranty period If Delta T requires that goods under warranty be returned to them from overseas for repair Delta T shall not be liable for the cost of carriage or for customs clearance in respect of such goods However Delta T requires that such returns are discussed with them in advance and may at their discretion waive these charges ...

Page 43: ...lay We normally expect to complete repairs within one or two weeks of receiving the equipment However if the equipment has to be forwarded to our original supplier for specialist repairs or recalibration additional delays of a few weeks may be expected For contact details see below Technical Support Users in countries that have a Delta T distributor or technical representative should contact them ...

Page 44: ...tion table 20 21 polynomial 20 21 Copyright 2 D Data logger 17 23 24 25 DL2e 16 23 24 DL6 15 24 GP1 14 15 24 other 17 Definitions 32 Description 5 Dielectric performance 21 refractive index 18 19 35 Dimensions 6 DL6 15 E EMC 31 Extension cables 10 F FCC compliance 31 Features 5 G GP1 14 15 24 H HH150 meter 12 HH2 25 HH2 Meter 13 I Installation buried 11 insertion rod 11 surface 11 L Linearisation ...

Page 45: ...Salinity 33 Sampling Volume 29 Servicing 43 Soil clay 19 20 32 35 36 39 mineral 18 20 22 36 37 40 organic 18 20 22 33 37 stony 11 soil calibrations 20 Specifications 2 26 T Technical support 42 43 Temperature response of soil moisture readings 28 Troubleshooting 24 V Volumetric Soil Moisture 32 W Warning Do not touch the pins 25 Water reading 25 ...

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