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UMS T5 User Manual

Pressure transducer tensiometer
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User Manual
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Pressure Transducer Tensiometer
© UMS GmbH München
Art.Nr. T5
Version 12/2009
Author: tk, ge, ma

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Summary of Contents for UMS T5

  • Page 1 User Manual Pressure Transducer Tensiometer © UMS GmbH München Art.Nr. T5 Version 12/2009 Author: tk, ge, ma...

  • Page 2: Table Of Contents

    3.4.5 Connection to a data logger 3.4.6 Tensiometer loggers DL6-te or GP1-te Service and maintenance Refilling 4.1.1 When do Tensiometers need to be refilled? 4.1.2 Refilling T5 in lab and field Testing 4.2.1 Calibration 4.2.2 Check the Offset Cleaning 2/48...
  • Page 3 Technical specifications Wiring configuration Accessories 8.3.1 Connecting and extension cables 8.3.2 Handheld measuring device 8.3.3 Tensiometer loggers 8.3.4 TV-batt power supply 8.3.5 T5 auger kit 8.3.6 T5-case Units for soil water and matrix potentials Index Your addressee at UMS 3/48...

  • Page 4: Introduction

    Electronic installation: Any electrical installations should only be executed by qualified personnel. Ceramic cup: Do not touch the cup with your fingers. Grease, sweat or soap residues will influence the ceramic's hydrophilic performance. Do not twist the T5 shaft against the sensor body! 4/48...

  • Page 5: Content Of Delivery

     Polyethylene bottle with 250 ml of water  Filling tube for shafts longer than 10 cm  Evacuation syringe with acrylic adapter for T5 sensor body  Evacuation syringe for T5 shaft  Water reservoir syringe for T5 shaft ...

  • Page 6: Foreword

    Yours, Georg von Unold 1.4 Guarantee UMS gives a guarantee of 12 months against defects in manufacture or materials used. The guarantee does not cover damage through misuse or inexpert servicing or circumstances beyond our control. The guarantee includes substitution or repair and package but...

  • Page 7: Tensiometer T5 And T5X

    The atmospheric reference pressure is provided through a membrane on the cable, a distinctive patented method. The T5 Miniature Tensiometer is specially designed for punctual measurements, e. g. in soil columns, pots or laboratory lysimeters, or when the measurement of a minimal span is desired.

  • Page 8: Typical Applications

    -450 kPa, but this is an exception and cannot be guaranteed. The T5x is identical with the T5 but has a different ceramic. The extended measuring range is made possible by the effect called boiling retardation, the special ceramic with smaller pores and, as a necessary condition, an absolutely gas free filling.

  • Page 9: Specific Notes

    Introduction 1.6.5 Specific notes  T5 and T5x are not suitable for dry soils and they are not frost resistant.  When installed in the field provide sufficient protection.  The less air is inside the cup and the better the soil's conductivity is, the faster the Tensiometer will respond to tension changes.

  • Page 10: Quick Installation Guide

    1. Drill a hole with the required diameter and depth. Mark the installation depth on both auger and T5 shaft. 2. Connect the T5 to a readout device, for example a data logger for continuous measurements or the INFIELD7 handheld device for spot readings.
  • Page 11 (white) Teflon membrane and through the cable. Sealed cable The T5 can be completely buried if required. If buried cables should be protected Sensor body The incorporated piezoelectric pressure sensor measures the soil water tension against atmospheric pressure.

  • Page 12: Sensor Description

    Sensor description 2 Sensor description 2.1 Design 2.1.1 Body and shaft The sensor body is made of acrylic glass and incorporates the pressure transducer and all electronic parts. The corpus is backfilled with resin to hermetically seal the electronics and make the body watertight.

  • Page 13: The Ceramic Tip

    Compared to conventional porous ceramic the cup is much more durable. The bubble point of a T5 cup is about 200 kPa, of a T5x about 500 kPa. If the soil gets dryer than this air passes through so the negative pressure inside the cup decreases and the readings go down to 0 kPa.

  • Page 14: Installation

    If the column is refilled care should be taken to achieve the best possible homogenous distribution and evenly compaction. Bear in mind a possible shrinking of backfilled columns when T5 are installed through the cylinder. On tillage sites (with plants) root spreading and growth during the measuring period should be considered.

  • Page 15: Ideal Conditions For Installation

    Installation 3.1.4 Ideal conditions for installation For the installation of Tensiometers, the ideal conditions are:  Frost-free soil.  Wet coarse clay or loess.  Low skeletal structure (gravel). 3.1.5 Documentation For every measuring spot you should:  measure the installation spot from 2 reference points (A must for installations below the ground surface).

  • Page 16: Installation Procedure

    2. If the hole’s diameter is larger than 5 mm mix a paste of water and grinded soil material. 3. Connect the T5 to a readout device, for example a data logger for continuous measurements or the INFIELD7 handheld device for spot readings.

  • Page 17: Offset Correction For Non Horizontal Installations

    The pressure transducer is calibrated without a cup. Thus, no compensation is required for horizontal installations. If a T5 or T5x is installed in a non horizontal position, the vertical water column draws on the pressure sensor and causes an offset shift.

  • Page 18: Connecting T5 And T5X

    3.4.1 Spot readings with the INFIELD7 T5 and T5x are fitted with a 4-pin plug. The plug can be connected directly to an INFIELD7 handheld measuring device for taking spot readings of the soil water tension. The INFIELD7 displays and stores the soil water tension readings.

  • Page 19: Tv-Batt Tensiometer Power Supply

    TV-batt Tensiometer power supply The TV-batt power supply is specially designed for Tensiometers T3, T4, T4e and T5. It offers a stabilized 10,6 V power supply, but with supply minus = -5 V and supply plus = +5,6 V. Therefore the output signal will have a logger specific signal level.

  • Page 20: Service And Maintenance

    95 kPa). By diffusion and slight leakage the reading will slowly drop within months. If the soil dries out and reaches the bubble point (-200 kPa for T5; -500 kPa forT5x), the tension will decrease rapidly as air will enter the cup.
  • Page 21 Service and maintenance 5. Function test The T5-set includes: Shaft auger & Deionised water body auger Capillary tube Drop syringe Filling syringe for the shaft Vacuum syringe with pressure transducer adapter Vacuum syringe Pack of paper tissues for the cup...
  • Page 22 Infield7 or a voltmeter and to -80 kPa within 10 seconds the power supply. T5 filling is ok. If this is not the case the T5 needs to be refilled. 2. Wrap a dry paper towel (kitchen roll) around the cup to 4.
  • Page 23 Service and maintenance The pressure sensor diaphragm is inside the small hole on the pressure sensor body (approx. 2 mm). It is very sensitive and must never be touched! It can be destroyed even by slightest contact! No contamination should get on the sealing and gasket. Degas the cup If the cup is completely dry just put the shaft in a beaker with deionised or distilled water over night.
  • Page 24 Service and maintenance 3. Insert the ceramic cup into 4. Take off the tube from the the tube as far as possible with syringe. Leave the shaft inside the ceramic pointing inside. the tube. The cup’s tip should be close to Remove all air from the syringe the syringe nozzle.
  • Page 25 8. Now insert the threaded side syringe with the 2 black spacers of the T5 shaft completely into and the O-ring on the tube. the tube. Pull up 10 ml water. Roll up the O-ring so the shaft is...
  • Page 26 Service and maintenance There should be no air inside the In case fill in some drops of tube before inserting the shaft water into the tube with the again. syringe. Reattach the syringe and pull it up until the spacers snap in. Leave the syringes on the shaft.
  • Page 27 Service and maintenance 3. Insert the sensor body. If you 5. Take off the tube and remove rotate the sensor it will slip in the air from the syringe. easier. Leave the sensor inside the adapter. 6. Squeeze the tube to remove any air inside while reattaching the syringe.
  • Page 28 Service and maintenance 6. Pull up the syringe until the Leave both syringe assemblies spacers snap in. for at least 2 hours (the longer The Tensiometer water now is the better). degassing. Reassembling 1. Take of the tubes from the The piston must not snap in shaft.
  • Page 29 Service and maintenance 3. Now remove last 5. Now remove sensor remaining bubbles: draw up the body. syringe once more and release it slowly. Now take off the syringe and remove the bubble inside. 6. Add one drop of water onto the shaft so a bulge of water overlaps the shaft ...
  • Page 30 Service and maintenance 7. … and carefully screw in the shaft into the senor body. Continuously check pressure with the INFIELD7: the pressure must not exceed 1 bar You will clearly notice the point when the shaft hits the o-ring inside the sensor body.
  • Page 31 If this is the case, the T5 is filled perfectly. To find out the maximum measuring range of this T5 hold the ceramic tip in the headspace of the bottle over the water. When you move the ceramic away from the water surface the air gets dryer and the suction rises.

  • Page 32: Testing

    0 kPa. There are two ways to check the offset. 1. Connect the Tensiometer to a readout device. Place the T5 in a beaker and fill the beaker with de-ionized water up to the centre of the sensor body (see 3.4.) Wait until the reading is stable.

  • Page 33: Cleaning

    (grain size 150...240). 4.4 Storage If the T5/T5x should not be used for a year or more then empty shaft and sensor body to avoid algae growth. Store both in a dry place. 5 Protecting the measuring site 5.1 Theft and vandalism...

  • Page 34: Useful Notes

    The bubble point of the porous cup The bubble point of a porous, hydrophilic structure is specified by the wetting angle and the pore size. The cups used for UMS Tensiometers have a bubble point far beyond the measuring range (8.8 bar).

  • Page 35: Boiling Retardation

    – the Tensiometer keeps on measuring beyond the boiling point. To achieve this the T5(x) must have an absolutely bubble free filling. Some T5x can go down to -250 kPa before they run dry, occasionally even a range of -450 kPa is achievable.

  • Page 36: Maximum Measuring Range And Data Interpretation

    Useful notes 6.2 Maximum measuring range and data interpretation The measuring range of Tensiometers is limited by the boiling point of water. At a temperature of 20°C the boiling point is at 2,3 kPa over vacuum. So with 20°C and an atmospheric pressure of 95 kPa the Tensiometer cannot measure a tension below -92,7 kPa, even if the soils gets drier than that.
  • Page 37 Useful notes If there will be rain before the soils reaches -2 bars, the Tensiometer cup will suck up the soil water. However, the soil water includes dissolved gas which will degas as soon as a dry soil again will increase the tension.

  • Page 38: Temperature Influences During Measurements

    Useful notes 6.3 Temperature influences during measurements If the sensor is not powered continuously the voltage should be switched on 10 seconds before a measurement. In this case, the self heating is negligible. The correlation of water tension to water content is temperature dependent.

  • Page 39: Osmotic Effect

    Thus, an influence of osmosis on the measurements is negligible because ion concentration differences are equalized quickly. If the T5 cup is dipped into a saturated NaCl solution the reading will be 1 kPa for a short moment, then it will drop to 0 kPa again.

  • Page 40: Appendix

    Appendix 8 Appendix 8.1 Technical specifications Material and dimensions Ceramic material Al2O3 sinter Bubble point T5 > 200 kPa Bubble point T5x > 500 kPa Length 6 mm,  5 mm Ceramic cup PMMA,  20 mm Sensor body Impact-proof PMMA,  20 mm...

  • Page 41: Wiring Configuration

    Appendix 8.2 Wiring configuration Configuration of T5 and T5x Tensiometer plug and the 4-wire CC-4 connecting cables: Signal Wire Function brown Supply plus blue Supply minus A-OUT+ white Analog output plus A-OUT- black Analog output minus 41/48...

  • Page 42: Accessories

    8.3.1 Connecting and extension cables Cables must be ordered additionally for each Tensiometer. UMS connecting or extension cables for data logger applications etc. Connecting cables CC-8/... are fitted with a female plug M12/IP67 and 12 cm wire end sleeves. Extension cables EC-8/... have one each male and female plug M12/IP67.

  • Page 43: Handheld Measuring Device

    INFIELD7 handheld measuring device for taking and storing spot readings of soil water tension. Offset correction of water column and installation angle. Suitable for all UMS - Tensiometers. The set comes with refilling tools in small carrying case. The tL-8/USB-Mini is a USB converter for data readout of the INFIELD7 via PC or laptop USB port, incl.

  • Page 44: Tv-Batt Power Supply

    Appendix 8.3.4 TV-batt power supply Tensiometer power supply unit for T3, T4, T5, suited in DL2e-logger extension frame (left), or as an open module (right). Item Art. no. TV-batt for DL2e logger TV-Batt/DL2e TV-batt module only TV-Batt/module 8.3.5 T5 auger kit Auger kit for T5, with shaft auger, length 250 mm length and sensor body auger, length 200 mm.

  • Page 45: Units For Soil Water And Matrix Potentials

    Appendix 8.4 Units for soil water and matrix potentials 45/48...

  • Page 46: Index

    Appendix 8.5 Index Auger ........43 Gas impermeability .....13 Guarantee......6 Boiling point ......35 Bubble point....13, 35 Installation procedure ...10, 16 Cable protection....34 Laboratory lysimeters ...7 Calibration......33 Lightning .......4 Ceramic ......13 Long cables ......4 Compensate the offset..17 Connecting cables ..18, 40, 41 Maximum pressure .....12 Data logger ......19 Degas the cup.....23...
  • Page 47 Appendix Temperature .......37 TV-batt ......19, 43 Typical applications ....8 Quartz clay......9 Vapour pressure ....37 Reassembling .....29 Reference air pressure ..12 Refilling .......20 White membrane ....12 Slurry........9 Soil columns ......7 Spot readings......18 Zero offset......31 T5-set .........21 47/48...

  • Page 48: Your Addressee At Ums

    D-81379 München Fax: +49-89-126652-20 Gmunderstr. 37 email: info@ums-muc.de Strictly observe rules for disposal of equipment containing electronics. Rücknahme nach Elektro G Within the EU: disposal through municipal waste WEEE-Reg.-Nr. DE 69093488 prohibited - return electronic parts back to UMS. 48/48...

This manual is also suitable for:

T5x

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