T5 Manual
Contents
1. 100 kPa min 160 kPa 100 kPa 85 kPa 160 kPa OkPa Tensiometer OkPa 100 kPa Piezometer 160 mV 160 kPa T5x 85 mV 85 kPa T5 0 mV 0 kPa 100 mV 100 kPa water level 0 5 kPa typ 10 6 VDC by TV batt recommended 5 15 VDC stabilized 1 3 mA at 10 6 V TV batt pH 3 pH 10 Limited to substances that do not harm silicon fluorosilicone EPDM PMMA and polyetherimide 40 48 Appendix rUMS 8 2 Wiring configuration Configuration of T5 and T5x Tensiometer plug and the 4 wire CC 4 connecting cables Ly brown PIN 1 Supply OX Si _ white PIN 2 Signal ES blue PIN3 Supply black PIN4 Signal Male Bun on Female plug on screen thick black sensor cable connecting cable Pin and wire configuration for UMS connecting cable CC 4 me ww m EN Supply plus ve Supymms Supply minus 2 A OUT white 2 Analog output plus A OUT Analog output minus 41 48 Appendix 8 3 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 Plugs are supplied with protective caps tem Am Length 5 m EC 4 5 Length 10 m EC 4 10 Length 20 m EC 4 202. Additional items Art no Clip on cable markers 30 times numbers O 9 KMT Plastic protection tube for cables are available with several diameters also dividable slotted tubes for easy re fitting 42 48 Appendix rUMS 8 3 2 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 Windows PC software tensioVIEW Wem o AArtno INFIELD7 set INFIELD7C USB PC adapter for Infield only tL 8 USB Mini 8 3 3 Tensiometer loggers 6 channel logger DL6 te for Tensio Data logger GP1 te with meters T3 T4 T4e T5 plus 1x counter channels for 2x Tensio 1x temperature alarm output 16 000 meters 2x temperature 2 readings memory IP68 4 pin sockets counters 1 relay output for extension cables EC 4 IP67 lem Art nm 6 channel logger incl software and data cable DL6 te 2 channel logger incl software and data cable GP1 te 43 48 Appendix 8 3 4 TV batt power supply DEER TIG GEOODEEEIK ER HERE PIET Tensiometer power supply unit for Ta T4 T5 suited in DL2e logger extension frame left or as an open module right lem tno TV batt for DL2e logger TV Batt
3. Strictly observe rules for disposal of equipment Ez containing electronics R cknahme nach Elektro G Within the EU disposal through municipal waste WEEE Reg Nr DE 69093488 prohibited return electronic parts back to UMS 48 48
4. to 10 3 kPa perfectly oong Kaes f A EME 122 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 Hold the ceramic as close to the water surface so the tension reading will rise slowly Depending on the filling quality the value will reach 85 to 450 kPa Then the value will rapidly drop to the vapour pressure around 90 kPa depending on the altitude Then immediately put some water on the ceramic and cover the ceramic with the protective bulb which should be filled with water to the half It will take one day until the Tensiometer will reach its initial value 31 48 Service and maintenance 4 2 Testing 4 2 4 Calibration When delivered Tensiometers are calibrated with an offset of 0 kPa when in horizontal position and a linear response The offset of the pressure transducer has a minimal drift over the years Therefore we recommend you check sensors once a year and re calibrate them every two years Return the Tensiometers to UMS for recalibration or use the calibration accessories available from UMS 4 2 2 Check the Offset If there is no pressure difference between the cup interior and the surrounding the signal should be 0 kPa There are two ways to check the offset 1 Connect the Tensiometer to a readout d
5. level but many loggers cannot do this In this case use a TV batt power supply 34 4 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 The Tensiometer signals are in a range of 1 V The TV batt is directly supplied by battery or 12 V mains power 3 4 5 Connection to a data logger Some logger types can measure bridge circuits directly other loggers require certain measures as the Tensiometer signal minus and the supply minus do not have the same ground 3 4 6 Tensiometer loggers DL6 te or GP1 te T5 and T5x can be connected directly and without further power supply to the special Tensiometer loggers DL6 te or GP1 te The DL6 te is a stand alone 6 channel logger with six 4 pin sockets All Tensiometer with 4 pin plug are connected to the DL6 te with extension cables EC 4 The GP1 te is a stand alone 2 channel logger with cable glands All Tensiometer with 4 pin plug are connected to the GPi te with connection cables CC 4 19 48 Service and maintenance 4 Service and maintenance 4 1 Refilling To assure a rapid and reliable measurement of the soil water tension the cup must be filled possibly bubble free with degassed water After dry periods or periods with a large number of wet and
6. 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 excludes shipping expenses Please contact UMS or our representative before returning equipment Place of fulfilment is Munich Gmunder Str 37 1 5 Durability The nominal lifespan for outdoor usage is 10 years but protection against UV radiation and frost as well as proper and careful usage extends the lifespan 6 48 Introduction UMS 1 6 Tensiometer T5 and T5x 1 6 1 Soils and soil water All water movements in soils are directly depending on the soil water tension as water in soils as well as on the surface always will move from a point of higher potential to a point of lower potential The majority of soil water flows take place at small water tensions Only Tensiometers allow the direct and precise measurement of these small tensions Naturally embedded soils are heterogeneous Not only precipitation and evaporation effect the processes but also texture particle size distribution cracks compaction roots and cavities Due to these heterogeneities the soil water tension varies Thus it is reasonable to have multiple measuring points at least in soil horizons close to the surface 1 6 2 Intended use The intended use of Tensiometers is the measurement of soil water tension respectively of matrix potential These Tensiometers work
7. respond to tension changes It does not make sense to refill a Tensiometer as long as the soil is dryer than 90 kPa T5 or 160 kPa T5x Using a quartz clay slurry is only recommendable in clayey soils and only if the drilled diameter is larger than the shaft diameter 5 mm In coarse sand or gravel soil a fine grained slurry paste would act as a water reservoir which would lead to a slower response The T5 can be installed in any position and orientation Bubbles are easily detectable through the transparent shaft Output signals are standardized 9 48 Introduction 1 7 Quick installation guide This chapter is only a summary of following chapters Please read the complete manual carefully before using the instrument T5 are filled and degassed when supplied and are ready for installation The procedure is the same for T5 and T5x In very soft soils the T5 can be inserted directly without drilling a hole As the shaft is fragile no force should be applied For hard soils a special auger kit for is available as an accessory art no TBT5 included in the T5 set When the T5 auger is used slurrying is unnecessary Installation procedure 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 During the installati
8. 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 This will result in a poor response the signal curve will get flatter and readings will only slowly adapt to the actual soil water tension Depending on the size of the developed bubble readings will get less close to the maximum fig 7 2 Interpretation of readings below 2 bars 10000 1000 100 Soil water tension 10 gs Tensiometer reading Matrix potential negative hPa 0 5 10 15 20 25 30 35 Time Fig 7 2 Tensiometer readings with tensions below 2 bar ooil water tensions normally change only slowly Therefore a signal curve with lot of jumps could be an indicator for example for loose contacts moisture in defective cables or plugs poor power supply or data logger malfunctions 3 48 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 The influence is low at tensions of O to 10 kPa O 0 6 kPa K but high for tensions over 100 kPa Y Water tension R Gas constant 8 31J mol K M Molecular weight p Vapour pressure po Saturation vapour pressure at soil temperature fr
9. to flow into the shaft Carefully remove the tube from the syringe nozzle and remove all air from the syringe see 6 25 48 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 Degas the sensor body 1 Now take the syringe with the 2 Hold the syringe upwards attached sensor body adapter and remove all air Pull up the syringe but not further than shortly before the spacers will snap in 26 48 Service and maintenance 3 Insert the sensor body If you rotate the sensor it will slip in easier 4 Pull up the syringe a few times Hold the syringe downwards so bubbles are collected inside the syringe 5 Take offthe tube and remove the air from the syringe Leave the sensor inside the adapter 6 Squeeze the tube to remove any air inside while reattaching the syringe 27 48 Service and maintenance 6 Pull up the syringe until the spacers snap in The Tensiometer water now is degassing Reassembling 1 Take of the tubes from the shaft I Taking off the syringe from the sensor body needs care to avoid damage of the pressure transducer Leave both syringe assemblies for at least 2 hours the longer the better Y The piston must not snap in as this
10. A UMS measure to know User Manual 15 T5x Pressure Transducer Tensiometer UMS GmbH M nchen Art Nr T5 Version 12 2009 Author tk ge ma Introduction Table of content 1 Introduction Safety instructions and warnings Content of delivery Foreword Guarantee Durability Tensiometer T5 and T5x Soils and soil water Intended use Typical applications Extended measuring range of the T5x Specific notes Quick installation guide oR Wh Sensor description 1 Design 1 1 Body and shaft 1 2 Pressure transducer 1 3 Reference air pressure 14 The ceramic tip 2 Analog output signals 3 Installation 1 Scientific measure ideas 1 1 Selecting the measuring site 1 2 Number of Tensiometers per level 1 3 Extension of the site 1 4 Ideal conditions for installation 1 5 Documentation 1 6 Selecting the installation angle 2 Installation procedure 3 3 Offset correction for non horizontal installations 3 4 Connecting T5 and T5x 3 4 1 Spot readings with the INFIELD7 3 4 2 Cables 3 4 3 General requirements 3 4 4 TV batt Tensiometer power supply 3 4 5 Connection to a data logger 3 4 6 X Tensiometer loggers DL6 te or GP1 te 4 Service and maintenance 4 1 Refilling 4 1 1 When do Tensiometers need to be refilled 4 1 2 Refilling T5 in lab and field 4 2 Testing 4 2 1 Calibration 4 2 2 Check the Offset 2 48 oco 1 4 000005 A Introduction 4 3 Cleaning 4 4 Storage 5 Protecting the
11. 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 Piemonte T5 auger kit TBT5 8 3 6 T5 case Service kit for t5 and T5x without a T5 incl refilling tools syringes etc auger kit connecting cable CC 4 1 5 all in blue case 35 x 30 x 8 cm Wem Arno T5 service kit T5 case 44 48 Appendix 1uepuadap Aypiwiny Jie Aap sly jurod DUDU ueueulJad 8190 0 8 0 GPL 000 01 CEO LY VOS vL 000 L CLL8 26 YOSVI 116896 cS 6lc 869266 FOSPL 19666 vOS vL m Sv cL S8 0 000 1 OOOOOO L Op 908 6 000000 OL 00L 000 00L 9g99 086 1000000 L 0 0L 000 01 G 990 86 000 001 e GL 005 L 6G 6O VI OOO SL Di 0 L 000 L 9 9086 000 0L pf d i n als LO T eo T oDuei Leg G FCO LG8 49 ouioisue L CNN pyepuels L Ayoedeo Dia Ad cO OD Dip ed 8 4 Units for soil water and matrix potent rT re a LI Se T1 i 45 48 Appendix 8 5 Index A AUI EE OE tu EUM 43 B Boiling point 35 Bubble point 13 35 C Cable protection 34 alIBrallOpt a mees ide 33 E EE 13 Compensate the offset 17 Connecting cables 18 40 41 D Data logger 19 Degas the cup 23 Degas the sensor body 27 Destruct
12. allation angle and depth 10 Protect the cables against rodent bites Lead the cables through plastic pipes or use the plastic protection tubes which are available as an accessory 3 3 Offset correction for non horizontal installations Centre of pressure transducer 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 Centre of ceramic i mm Ti Compensate the offset by calculation by entering the installation angle in the Infield7 for spot readings inthe configuration of a data logger by setting an offset The deviation is largest for a vertical water column at 0 The water column drawing on the pressure transducer is equal to the shaft length ranging from 2 to 20 cm The offset is shifted for 0 1 kPa per cm shaft length Example A 5 cm vertical column of water below the pressure sensor will create an 0 5 kPa offset This means that when the soil water tension is 0 kPa the sensor will indicate 0 5 kPa 1 cm water column corresponds to a pressure of 0 983 hPa 17 48 Installation 3 4 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
13. d Monitoring with data loggers Spot readings with the INFIELD7 For in the field applications it might be recommendable to use T4 T4e or T8 Tensiometers 1 6 4 Extended measuring range of the T5x The special version T5x is tested to reach a measuring range of 160 kPa when delivered To achieve this the T5x requires an absolutely bubble free filling You might notice that your T5x might even go down to 250 kPa before running empty sometimes even to 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 Do not allow the T5x ceramic to dry out by leaving it unprotected in air by drying out the tension might reach the destructive pressure Due to the finer pores of the ceramic the water conductivity is lower Therefore the response of a T5x is slower than with a standard T5 When the shaft is touched it might warm up This might cause a short time change of the pressure ed ed 8 48 Introduction UMS 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
14. drying out successions Tensiometers must be refilled Refilling is the easiest with the refilling tools included in the T5 set or T5 case A readout device for example the INFIELD7 is always needed to control the signal 4 1 1 When do Tensiometers need to be refilled Tensiometers need to be refilled the curve of the readings apparently gets flatter for example a rain event has no sharp peak but is round the maximum of 85 kPa is not reached anymore Refilling is only reasonable if the soil is moister than 90 kPa If the soil gets dryer than 85 kPa the readings will remain constant at the vapour pressure of water i e for example 92 7 kPa at 20 C and atmospheric pressure of 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 4 1 2 Refilling T5 in lab and field This chapter describes the refilling of T5 or T5x using the T5 set The procedure has 5 steps Check the T5 Tensiometer Degas cup and shaft Degas sensor Reassemble poe 20 48 Service and maintenance UMS 5 Function test The T5 set includes Shaft auger amp body auger Drop syringe Filing syringe for the shaft Pack of paper tissues 21 48 Service and maintenance Check the T5 1 First check if the T5 requires a refiling connect it to an Inf
15. electronic parts The corpus is backfilled with resin to hermetically seal the electronics and make the body watertight 2 1 2 Pressure transducer The piezoelectric pressure sensor measures the soil water tension against the atmospheric pressure The atmospheric pressure is conducted through a watertight diaphragm the white 2 cm long tube on the cable and through the cable to the reference side of the pressure sensor Y The non destructive maximum pressure is 3 bar 300 kPa Higher pressure will damage the sensor and absolutely must be avoided High pressures can appear for example when cup and sensor are reassembled when inserted in wet clayey soils or in tri axial vessels 2 1 8 Reference air pressure The reference atmospheric air pressure is conducted to the pressure transducer via the air permeable white Teflon membrane and through the cable The membrane does not absorb water Water will not pass through the membrane into the cable but moisture inside the cable will leave the cable through the membrane Y The white membrane on the cable must always have contact to air during a measurement and should never be submersed into water 12 48 Sensor description UMS 2 14 The ceramic tip To transfer the soil water tension as a negative pressure into the Tensiometer a semi permeable diaphragm is required This must have good mechanical stability and water permeability but also have gas impermeability The Tensiometer c
16. eters are filled with water and therefore are sensitive to frost Protect Tensiometers from frost at any time Never leave Tensiometers over night inside a cabin or car when freezing temperatures might occur Tensiometers normally are not damaged when the cup is installed in a frost free soil horizon in general below 20 cm ed Excess pressure The maximum non destructive pressure is 300 kPa 3 bar 3000 hPa Higher pressure which might occur for example during insertion in wet clayey soils or during refilling and reassembling will destroy the pressure sensor ed Electronic installation Any electrical installations should only be executed by qualified personnel ed 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 Introduction UMS 1 2 Content of delivery The delivery of a T5 or T5x includes Tensiometer calibrated and filled with 4 pin plug M12 IP67 with plug cap This manual Rubber protection cap filled with water to the half for keeping the ceramic moist and clean For available accessories see chapter Accessories The delivery of a T5 set or T5x set includes Blue plastic transport case Tensiometer filled and calibrated with 4 pin plug M12 IP67 plug with protective cap This manual Rubber protection cap filled to the half with water
17. evice 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 If there are bubbles inside the cup this might take a while Now the reading is the approximate offset The value should be between 0 3 and 0 3 kPa 2 To check the zero point more precisely shaft and sensor body need to be disassembled Y The pressure sensor diaphragm is inside the small hole on the pressure sensor body 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 Before reassembling cup and sensor body carry out the degassing procedure see chapter Refilling After taking off the shaft shake the pressure sensor to remove water from the pressure transducer hole The offset is acceptable when the reading is between 0 3 and 0 3 kPa 32 48 Protecting the measuring site UMS 4 3 Cleaning Clean ceramic and sensor body only with a moist towel If the ceramic is clogged it may be flushed it with Rehalon If the pores are clogged with clay particles saturate the ceramic and then polish the ceramic surface with a wetted waterproof sandpaper 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 vandali
18. from 100 kPa water pressure level to 85 kPa suction soil water tension the T5x even to a lower tension If the soil dries out the Tensiometer runs empty and must be refilled as soon as the soil is sufficiently moist again ooil water and Tensiometer water have contact through the ceramic which is porous and permeable to water A wetted porous ceramic creates an ideal pore water interface The soil water tension is directly conducted to the pressure transducer which offers a continuous signal 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 With an active surface of only 0 5 cm and a diameter of 5 mm the ceramic tip has all advantages of small dimensions little soil disturbance punctual pick up and fast response 7 48 Introduction 1 6 3 Typical applications Typical applications of the T5 and T5x Punctual measurement of water potential Miniature soil column studies e g in combination with micro water samplers and soil temperature probes Determination of pF wc and K Psi in soil columns soil cores or soil sampling rings Determination of leachate and capillary water movements Controlling irrigation Pot experiments Measurements in the upper soil horizons in the fiel
19. h the required diameter and depth Mark the installation depth on both auger and T5 shaft 2 f the holes 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 During the installation the Tensiometer reading has to be controlled at any time Especially in wet clayey soils a high pressure might develop while inserting the T5 A pressure of over 2 bar will destroy the pressure transducer Stop or slow down the insertion to allow pressure relieve 4 f you use a slurry paste pour it into the hole 5 Pull off the water filled rubber cap from the shaft Do not turn the cap as this might unscrew the shaft 6 Gently and steadily insert the T5 down to the mark while checking the reading Never turn the T5 inside the borehole as this might loosen the shaft The less air is inside the cup and the better the soil s conductivity is the faster the Tensiometer will respond to tension changes 7 Put the protection cup on the plug whenever the plug is not connected Dirt will reduce the water tightness of the plug Hemember to put the protective cap back on the plug after taking spot readings with the INFIELD7 16 48 Installation UMS 8 Connect the signal cables as described in the chapter Connecting the T5 or T5x 9 Write down the serial number position inst
20. ield7 or a voltmeter and power supply b VEE n 2 Wrap a dry paper towel Kitchen roll around the cup to dry the ceramic surface TY EN o E Js 3 Paez Y With short shaft lengths cover the ceramic with a paper towel to avoid contamination 3 Now wave the T5 tip around in the air If the reading will rise to 80 kPa within 10 seconds the T5 filling is ok If this is not the case the T5 needs to be refilled IMFIELD 7 ol 4 To disassemble the shaft hold the sensor body and turn oif the shaft counter clockwise 22 48 Service and maintenance UMS Y The pressure sensor diaphragm is inside the small hole on the pressure sensor body approx 22 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 Do not fill any water inside the shaft If water intrudes from inside and outside bubbles are trapped inside the ceramic pores But if the water only intrudes from the outside and soaks into the inside any air bubbles are pushed out 1 Take the syringe with the 2 Remove all air from the short rubber tube syringe Pull up 10 ml of deionised or Now block the tube with your distilled water finger and pull up the syringe A This creates vacuum inside the syringe and dis
21. 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 Take documenting photos before during and after installation Save a soil sample Write down installation depth and angle with each sensor identification serial number Mark all connecting cables with the corresponding sensor identification serial number or logger channel on each end Clip on number rings are available as an accessory 3 1 6 Selecting the installation angle An installation position would be ideal if the typical water flow is not disturbed by the Tensiometer No preferential water flow along the shaft should be created If the ceramic cup is positioned higher than the sensor body the first bubble that may appear inside the shaft will block the water exchange and stop the Tensiometer to measure 15 48 Installation 3 2 Installation procedure The following tools are reguired for installation in the field An auger with diameter 5 mm preferably the UMS Tensiometer auger kit TBT5 Rule spirit level angle gauge marker pen Minute book and camera for documentation of site and soil profile Perhaps PE plastic bags for taking soil samples from the site 1 Drill a hole wit
22. ive pressure 4 E Extension cables 41 F LOS oro EE eae 4 34 46 48 G Gas impermeability 13 Guarantee a aaaananananan0n0nn 6 I Installation procedure 10 16 L Laboratory lysimeters 7 Blei ae LA a cuu AE 4 Long cables 4 M Maximum pressure 12 O OSCE iade ae 33 OSMOSIS ees ees ee 38 Output signals 13 P PUO S 40 Porous ceramic 13 welcome DET 7 Pressure sensor 12 Appendix Q Quartz clay 9 R Reassembling 29 Reference air pressure 12 Refilling 20 S wills OE N NE diets 9 Soil columns 7 Spot readings 18 T T5 set 21 47 48 Temperature 37 TV batt 19 43 Typical applications 8 V Vapour pressure 37 W White membrane 12 Z Zero offset 31 Your addressee at UMS Your addressee at UMS Sales Georg v Unold Tel 49 89 126652 15 Email govu ums muc de About this manual Thomas Keller Tel 49 89 126652 19 Email tk ums muc de UMS GmbH Ph 49 89 126652 0 UMS D 81379 M nchen Fax 49 89 126652 20 mno he Gmunderstr 37 email info ums muc de Ce
23. measuring site 5 1 Theft and vandalism 5 2 Cable protection 5 3 Frost 6 Useful notes 6 1 Extended measuring range 6 1 1 The bubble point of the porous cup 6 1 2 The vapour pressure of water 6 1 3 Boiling retardation 6 2 Maximum measuring range and data interpretation 6 3 Temperature influences during measurements 6 4 Vapour pressure influence on pF WC 6 5 Osmotic effect 7 Troubleshooting 8 Appendix 8 1 Technical specifications 8 2 Wiring configuration 8 3 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 8 4 Units for soil water and matrix potentials 8 5 Index Your addressee at UMS 3 48 33 33 Introduction 1 Introduction 1 1 Safety instructions and warnings Electrical installations must comply with the safety and EMC requirements of the country in which the system is to be used Please note that any damages caused by handling errors are out of our control and therefore are not covered by guarantee Tensiometers are instruments for measuring the soil water tension soil water pressure and soil temperature and are designed for this purpose only Please pay attention to the following possible causes of risk Lightning Long cables act as antennas and might conduct surge voltage in case of lightning stroke this might damage sensors and instruments ed Frost Tensiom
24. might be necessary to take soil samples Ifthe 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 Fine roots might develop around the ceramic cup as it is a poor but assured water source Avoid the root zone if possible or replace the Tensiometer from time to time 3 12 Number of Tensiometers per level The lower the level the less the variations of water potentials are In sandy or pebbly profundities one Tensiometer per depth is sufficient Close to the surface about 3 Tensiometers per level are recommendable Guiding principle More heterogeneous sites and soil structures require a higher number of Tensiometers 3 1 3 Extension of the site Large distance along with high equidistance between the measuring spots will reduce the influence of sectional heterogeneity To determine the water flow according to Darcy two Tensiometers per horizon or required one each in an upper and lower level of this horizon Max recommendable cable lengths for T5 and T5x are 20 meters Accuracy long cables cause a reduction of the accuracy Lightning cables act as antennas and should always be as short as possible 14 48 Installation UMS 3 1 4 Ideal conditions for
25. might damage the pressure transducer 2 Hold the syringe and the syringe piston securely Bear in mind there is still vacuum inside Press in the spacers and slowly release the piston 28 48 Service and maintenance 3 Now remove the last remaining bubbles draw up the syringe once more and release it slowly Now take off the syringe and remove the bubble inside 3 Reattach the sensor body and draw up the syringe again Tap on the sensor body to release any bubble Y Let the piston release slowly 5 Now the sensor body remove 6 Add one drop of water onto the shaft so a bulge of water overlaps the shaft 29 48 Service and maintenance 7 and carefully screw in the shaft into the senor body 8 Continuously check the pressure with the INFIELD7 the oressure must not exceed 1 bar You will clearly notice the point when the shaft hits the o ring inside the sensor body From this point do only another quarter turn 30 48 Service and maintenance Check the T5 Zero offset Place the T5 flat on the table Put a drop of water on the cera mic cup Now the potential is zero and the reading should be between 3 hPa and 3 hPa 0 3 kPa Check the response Open the bottle with the water Dry the ceramic surface with a clean tissue Then wave the cup in the air The reading should rise to 80 kPa within 10 seconds If this is the case the T5 is filled
26. of water At a temperature of 20 C the vapour pressure of water is 2 3 kPa against vacuum With an atmospheric pressure of 100 kPa and at 20 C the water will start to boil or vaporize as soon as the pressure drops below 2 3 kPa against vacuum i e 97 7 kPa pressure difference to an atmospheric pressure of 100 kPa the Tensiometer drops out The measuring range at 100 kPa 20 C is limited to 97 7 kPa Atmospheric pressures announced by meteorological services are always related to sea level Thus the true pressure in a height of 500 meters over sea level is for example only 94 2 kPa although 100 kPa are announced Then the measuring range at this height at 20 C is even limited to 91 9 kPa If the soil gets drier than the maximum possible measuring range the reading will remain at this value and then drop gradually towards zero If the soil gets as dry as the bubble point a spontaneous equalisation with the atmospheric pressure occurs Air enters the cup and the reading will rapidly go to zero 34 48 Useful notes UMS True pressure in heights over sea level at an atmospheric pressure related to sea level as published by meteorological services Height over sea Atmospheric Max measuring level meter pressure kPa range at 20 C kPa 0 101 3 99 0 500 95 5 93 2 1000 89 9 87 6 1500 84 6 82 3 2000 79 5 77 2 2500 74 5 72 2 3000 70 1 67 8 6 1 3 Boiling retardation Water needs a nucleation site to boil As o
27. om Scheffler Straub Grigull 6 4 Vapour pressure influence on pF WC If the temperature of a soil with a constant water content rises from 20 C to 25 C the soil water tension is reduced for about 0 85 kPa due to the increased vapour pressure which antagonizes the water tension Pressure change per 12 15 Vie 25 72 14 Kelvin in hPa 38 48 Troubleshooting UMS 6 5 Osmotic effect The ceramic has a pore size of r 2 0 3 um and therefore cannot block ions 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 7 Troubleshooting Please refer to our webpage where you will find a regularly up dated list of FAQs http www ums muc de en support fag tensiometer html 39 48 Appendix 8 Appendix 8 1 Technical specifications Material and dimensions Ceramic material Bubble point T5 Bubble point T5x Ceramic cup Sensor body Shaft material Sensor cable Length Plug Measuring range T5 T5x Water tension Water level Output signal Pressure Accuracy Power supply Supply voltage Vin Current consumption Substance sustainability pH range AI2O3 sinter 200 kPa 500 kPa Length 6 mm 2 5 mm PMMA 20 mm Impact proof PMMA 20 mm 1 5m Male 4 pin thread M12 IP67 85 kPa
28. on the Tensiometer reading has to be controlled at any time Especially in wet clayey soils a high pressure might develop while inserting the T5 A pressure of over 3 bar will destroy the pressure transducer Stop or slow down the insertion to allow pressure relieve 3 Carefully remove the water filled rubber cover from the tip and gently and steadily insert the T5 down to the mark Never turn the T5 inside the borehole as this might loosen the shaft Y Put the protection cup on the plug whenever the plug is not connected Dirt will reduce the water tightness of the plug Hemember to put the protective cap back on the plug after taking spot readings with the INFIELD7 10 48 Introduction A UMS maaaure to know Reference air pressure The reference atmospheric air pressure is conducted to the pressure transducer via the air permeable 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 Acrylic glass shaft Shafts are available with lengths from 2 to 20 cm s High grade porous ceramic cup SES Filled with degassed water 11 48 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
29. sm The site should be protected against theft and vandalism as well as against any farming or field work Therefore the site should be fenced and signposts could give information about the purpose of the site 5 2 Cable protection Outdoors cables should be protected against rodents with plastic protection tubes UMS offers dividable protection tubes as accessory In the lab the cables should be fixed so they are not accidentally pulled away and that there is no risk of stumbling 5 3 Frost Tensiometers are filled with water and are endangered by frost T5 and T5x should only be use in frost free surroundings Do not store filled Tensiometer at temperatures below 0 C Do not leave filled Tensiometers over night in your car in a measuring hut etc Do not fill the Tensiometers with Ethanol as this is corrosive for some materials i e PMMA and will destroy these 33 48 Useful notes 6 Useful notes 6 1 Extended measuring range The extent of the measuring range of a Tensiometer is influenced by 3 factors 1 The bubble point 2 The vapour pressure boiling point 3 The boiling retardation 6 1 1 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 Therefore the bubble point has no limiting influence 6 1 2 The vapour pressure
30. soil water tension The INFIELD7 displays and stores the soil water tension readings Stored readings can be downloaded with the USB converters tL 8 USB or tL 8 USB Mini which are available as accessory Remember to put the protective cap back on the plug after taking spot readings with the INFIELD7 3 4 2 Cables Connecting and extension cables are required for connecting T5 and T5x to a data logger or other data acquisition device Find cables in the chapter Accessories Cover plugs with the supplied protective cap if not connected 3 4 3 General requirements The pressure transducer is a non amplified bridge circuit which is calibrated for 10 6 VDC and requires a stabilized power supply Other supply voltages are possible but the output signal range has to be recalculated In a full bridge the signal must be measured differentially This means do not measure only signal plus against common ground but measure the voltage drop between signal minus against common ground and signal plus against common ground Y The supply voltage has to be constant and stabilized Y The supply voltage must not exceed 18 VDC If the Tensiometer is not permanently powered the warm up before a measurement should be at least 10 seconds The 9996 value is reached after 1 100 seconds If the Tensiometer is supplied with 10 6 VDC the output signal range is around 5 3 VDC A data logger must have the capability 18 48 to measure such a signal
31. solved gas is released Turn the sti evacuated syringe to collect all bubbles Hold the syringe upright unblock the tube and remove all air Repeat this procedure until no bubbles appear anymore Take care to avoid bubbles 23 48 Service and maintenance 3 Insert the ceramic cup into the tube as far as possible with the ceramic pointing inside The cup s tip should be close to the syringe nozzle Pull up the syringe just a little bit Hold the syringe down wards and tap on it to loosen all bubbles There should be no air inside the tube around the ceramic In case fill in some water with the syringe 4 Take off the tube from the syringe Leave the shaft inside the tube Remove all air from the syringe 5 Put the tube back on the syringe 24 48 Service and maintenance 6 Now take the vacuum syringe with the 2 black spacers and the O ring on the tube Pull up 10 ml water 7 Degas the water as described above 8 Now insert the threaded side of the T5 shaft completely into the tube Roll up the O ring so the shaft is securely fixed the O ring should not be in the range of the thread but beyond the end of the thread Y Be careful to keep the parts clean so there will be no leaking when vacuum is applied 9 Now pull up the syringe until both spacers snap in Turn the syringe to collect all bubbles but do not tap on the syringe Release the spacers and allow water
32. to keep the cup wet and clean Pack of paper tissues Polyethylene bottle with 250 ml of water Filing 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 Syringe with pipette tip Spare pipette tip Gouge auger diameter 5 mm length 200 mm Sensor body auger diameter 18 mm length 200 mm Connecting cable 1 5 m length 5 48 Introduction 1 3 Foreword Measuring systems must be reliable and durable and should reguire a minimum of maintenance to achieve target oriented results and Keep the servicing low Moreover the success of any technical system is directly depending on a correct operation At the beginning of a measuring task or research project the target all effective values and the surrounding conditions must be defined This leads to the demands for the scientific and technical project management which describes all quality related processes and decides on the used methods the technical and measurement tools the verification of the results and the modelling The continuously optimized correlation of all segments and it s quality assurance are finally decisive for the success of a project oo please do not hesitate to contact us for further support and information We wish you good success with your projects Yours Georg von Unold 1 4 Guarantee UMS gives a guarantee of 12 months against defects in manufacture
33. up consists of porous ceramic Al203 sinter material The special manufacturing process guarantees homogeneous porosity with good water conductivity and very high firmness 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 With these characteristics this material has outstanding suitability to work as the semi permeable diaphragm for Tensiometers Ceramic cup Do not touch the cup with your fingers Grease sweat or soap residues will influence the ceramic s hydrophilic performance Do not allow the T5 ceramic to dry out by leaving it unprotected in air By drying out the bubble point might be reached the reading will go to O kPa and air might enter the cup which requires a refilling 2 2 Analog output signals The pressure transducer offers the soil water tension as a linear output signal with 1 mV corresponding to 1 kPa As the pressure transducer is a Wheatstone full bridge it has to be connected in a certain mode Please read chapter 3 5 3 and the manual of your display unit or data logger before connection 13 48 3 Installation 3 1 Scientific measure ideas 3 1 1 Selecting the measuring site The installation spot should be representative for the soil which should be surveyed For selection it
34. ur Tensiometers have polished surfaces and a gas free filling the so called boiling retardation occurs 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 As this is exceptional there is no guarantee for this measuring range 35 48 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 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 The readings remain at a constant value fig 7 1 between day 10 and 16 Interpretation of readings to 2 bars 100000 10000 1000 100 Soil water tension g lensiometer reading Matrix potential negative hPa Time Fig 7 1 Tensiometer readings with tensions to 2 bar If the soil will get even drier and reaches 2 bar the ceramic s bubble point is reached The cup water will run out quickly and the reading of the air filled cup will go to zero fig 7 1 day 16 19 36 48 Useful notes UMS If there will be rain before the soils reaches 2 bars the Tensiometer cup will
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