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1. 0 47 0 45 0 43 Angle to vertical line 45 60 70 75 80 90 Offset correction in kPa 0 35 0 25 0 17 0 13 0 09 0 The offset is entered as in your logger if you regard the soil water tension to be negative 0 85 kPa 22 58 20 YEARS Installation UMS 3 5 Connecting T8 3 5 1 Spot reading with the INFIELD7 handheld The T8 is fitted with an 8 pin plug The plug can be connected to an INFIELD7 handheld measuring device The INFIELD7 displays and stores the soil water tension the soil temperature and the filling status 3 5 2 Connection to a data logger For connecting T8 to a data logger or any other data acquisition devices connecting and extension cables are required Find T8 cables in the chapter Accessories The supply voltage does not has to be stabilized If the Tensiometer is not permanently powered the warm up before a measurement should be at least 10 seconds Y The Tensiometer plug should be covered with the supplied protective cap anytime the T8 is not connected to an extension cable F Never connect the signal outputs of the T8 to a supply voltage source F The supply voltage must not exceed 18 VDC Tightly screw together all plugs of connecting cables CC 8 or extension cables EC 8 Do this again after a few minutes as only then the connections will be absolutely water proof 23 58 Installation 3 5 3 Error caused by single ended co
2. Syringe De airing tube Fig 5 2 Downwards installation the marked tube is the refilling tube the unmarked tube the de airing tube Se De airing tube Mark on shaft De airing tube with black mark Fig 5 3 Upwards installation the marked tube is the de airing tube the unmarked tube the refilling tube Procedure see fig 5 2 amp 5 3 37 58 Service and maintenance Connect the T8 to the measuring device and keep an eye on the pressure signal at any time Two steel capillary tubes come out from the T8 shaft The refilling tube and the de airing tube In a downwards installation the marked tube is the refilling tube in an upwards installation the not marked tube is the refilling tube Pull off the rubber tube from the refilling tube Connect the tube of the syringe to the refilling tube Carefully inject water into the refilling tube until no bubbles come out of the de airing tube Fill in at least 25 ml Check the pressure at any time Remove the syringe Put a drop of water on both rubber and steel tube s end Connect both 5 1 4 Refilling with a vacuum pump To achieve the maximum possible measuring range Tensiometers can be completely degassed using a vacuum pump This method can be applied for installed Tensiometers in any installation angle as well as for not installed Tensiometers For refilling tubes longer than 5 meter this method should always be used The UMS refill kit BKTex includes
3. 2 58 Tensiometer T8 4 T8 configuration with tensioVIEW 4 1 tensioLINK USB converter 4 2 Work with tensioVIEW 4 2 1 Menu 4 2 2 Current readings 4 2 3 Stored readings 4 2 4 Configuration of a device 4 3 Configuration settings for T8 5 Service and maintenance 5 1 Refilling 5 1 1 When do Tensiometers need to be refilled 5 1 2 Refilling in the lab 5 1 3 Refilling in the field 5 1 4 Refilling with a vacuum pump 5 2 Testing 5 2 1 Calibration 5 2 2 Check the Offset 6 Protecting the measuring site 6 1 Theft and vandalism 6 2 Cable protection 6 3 Frost 6 3 1 Protection against frost 6 3 2 Emptying the T8 6 4 Lightning protection and grounding 7 Useful notes 7 1 Maximum measuring range and data interpretation 7 2 Temperature influences 7 3 Vapor pressure influence on pF WC 7 4 Osmotic effect 7 5 Using a T8 as a piezometer 8 Troubleshooting 9 Appendix 9 1 Technical specifications 9 2 Wiring configuration 9 3 Accessories 9 3 1 Connecting and extension cables 9 3 2 Handheld measuring device 9 3 3 Tensiometer augers 9 3 4 Refill kits 9 3 5 tensioLINK accessories 9 4 Units for soil water and matriy potentials Your addressee at UMS 3 58 Tensiometer T8 1 Tensiometer T8 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 han
4. 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 l Before reassembling cup and sensor body carry out the degassing procedure see chapter 5 1 2 Refilling in the lab For testing the signal gradient a calibration kit is required 40 58 20 YEARS Protecting the measuring site UMS 6 Protecting the measuring site 6 1 Theft and vandalism 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 6 2 Cable protection Cables should be protected against rodents with plastic protection tubes UMS offers dividable protection tubes as accessory For long term studies we recommend to dig cables a few centimeters below soil surface inside protection tubes 6 3 Frost 6 3 1 Protection against frost Tensiometer are filled with water and therefore are endangered by frost Do not store filled Tensiometer at temperatures below 5 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 Also it is not recommended to fill the Tensiometers with Decali
5. e g filling status insufficient this voltage value will be put on the analog output DAC output range Set the output range of the analog reading to 0 to 1 V 0 to2 Vor 0 to 5 V A sensor reading will be amplified within this range for example 100 kPa to 100 kPa can correspond to 0 to 2 V DAC temperature output range Output range for temperature DAC pressure output range Output range for pressure I Digital output Digital output power saving Activate the power saving function of the digital output Any burden connected to the digital output will be powered shortly every 5 seconds e g a LED will blink every 5 s indicating a malfunction Function of the digital output Evaluation through a table If the digital output is used for control of the filling status 1 indicates a poor filling status If used as a comparator the value of a reading is compared to the set threshold see Lower threshold If used as a window comparator the reading is compared with both threshold values In case the reading is in between both threshold values the digital output is set to 1 Associate reading to digital output This is the relevant reading for the comparator Associate depth to digital output The depth value for comparator 1 individual sensor see Associate depth DACA Invert digital output function If enabled all digital output functions will be inverted Lower threshold integer Integer part of the lower threshold or win
6. gt 0 0 6 kPa K but high for tensions over 100 kPa R T P WY In M Po Water tension R Gas constant 8 31J mol K M Molecular weight p Vapor pressure Po Saturation vapor pressure at soil temperature from Scheffler Straub Grigull 7 3 Vapor 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 vapor pressure which antagonizes the water tension Temperature 4 10 16 20 25 30 50 70 in C Pressure 0 6 0 9 1 2 1 5 1 9 2 5 7 2 14 change per Kelvin in hPa 7 4 Osmotic effect The ceramic has a pore size of r 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 T8 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 46 58 20 YEARS Troubleshooting UMS 7 5 Using a T8 as a piezometer The T8 can be used as a piezometer for measuring water over pressure Calculate the height of the water level with P Puo 8h hPa and E aa Puo E Ph2ol Density of water at 20 C 0 998205 kg dm3 at 4 C 1 0 kg dm3 Pa N qm N kg m qsec kg Pa qm m Pa kg qqm qsec A water column of 100 cm cau
7. This manual Plastic bottle protecting the ceramic cup must be filled to half with water to keep the cup wet a Rubber shaft water protection disk Calibration certificate with each order for conversion of electrical to physical values Refilling syringe For available accessories see chapter Accessories 1 3 Foreword Measuring systems must be reliable and durable and should require 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 modeling The continuously optimized correlation of all segments and its quality assurance are finally decisive for the success of a project We wish you good success with your projects Please do not hesitate to contact us for further support and information Yours Georg von Unold 5 58 Tensiometer T8 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 beyo
8. UMS User Manual T8 Long term Monitoring Tensiometer UMS GmbH M nchen Art no T8 Revision 12 2011 Authors an ge tk ma Tensiometer T8 Table of content 1 Tensiometer T8 1 1 Safety instructions and warnings 1 2 Content of delivery 1 3 Foreword 1 4 Guarantee 1 5 Durability 1 6 Tensiometer T8 1 6 1 Soils and soil water 1 6 2 Intended use 1 7 Quick start guide 2 Description of the T8 2 1 T8 parts 2 1 1 Body and shaft 2 1 2 Pressure sensor 2 1 3 Reference air pressure 2 1 4 Temperature sensor 2 1 5 Filling status indicator 2 1 6 The ceramic cup 2 2 Output signals 2 2 1 Analog 2 2 2 Digital 2 3 Serial interfaces 2 3 1 tensioLINK 2 3 2 SDI12 2 4 Software 2 4 1 tensioVIEW 2 5 Sensor logging 3 Installation 3 1 Concept planning and installation 3 1 1 Selecting the measuring site 3 1 2 Number of Tensiometers per level 3 1 3 Extension of the site 3 1 4 Length and solar protection of refilling tubes 3 1 5 Jacket tubes 3 1 6 Ideal conditions for installation 3 1 7 Documentation 3 2 Selecting the installation angle 3 2 1 Vertical with downwards angle 3 2 2 Horizontal with upwards angle 3 3 Installation procedure 3 4 Offset correction for non horizontal installations 3 5 Connecting T8 3 5 1 Spot reading with the INFIELD7 handheld 3 5 2 Connection to a data logger 3 5 3 Error caused by single ended connection 3 5 4 Connecting the indicator o oooo oo oo ouuanAn A
9. all required tools hand operated vacuum pump vacuum bottle with tube and syringe with valve Procedure see fig 5 4 amp 5 5 1 2 Connect the T8 to the measuring device and keep an eye on the pressure signal all the time In an downwards installation the marked tube is the refilling tube In an upwards installation the unmarked tube is the refilling tube Pull off the rubber tube from the refilling tube Degas the water inside the syringe as described above Connect the syringe to the refilling tube and close the valve Connect vacuum bottle and de airing tube With the vacuum pump evacuate the bottle to the maximum possible vacuum This will enlarge the remaining bubble inside the cup Now briefly open and close the valve of the syringe for a few times water is drawn into the Tensiometer while at the same time the air bubble is sucked into the vacuum bottle Repeat this 2 or 3 times until no bubbles come out anymore 38 58 20 YEARS Service and maintenance UMS 6 Close the valve of the vacuum bottle and remove the bottle Inject 5 ml of water from the syringe into the refilling tube Remove the syringe Put a drop of water on both rubber and steel tube s end Connect both Syringe Eu be g Rn A ET ON Refilling tube with black mark N WL Mark on shaft foe De airing tube C Manual or other vacuum pump Vacuum bottle Fig 5 4 Downwards installation the marked tube is the refillin
10. for taking and storing spot readings of soil water tension soil temperature and filling status Automatic offset correction of water column and installation angle Suitable for all UMS Tensiometers The set comes with refilling tools in small carrying case Item Art no a Infield7 set INEIELDTC U USB PC adapter for Infield only CC 8 1 5 9 3 3 Tensiometer augers Tensiometer gouge auger with specially shaped blade The tip of the blade has the same shape and diameter as the Tensiometer cup so the Tensiometer fits tightly into the borehole Thus no slurrying of the cup is necessary Set includes gouge auger and handle with hammering head Item Art no Auger with handle e 1 B 29 Extension rod length 100 cm TBE 100 52 58 Appendix 9 3 4 Refill kits e 7 ZS BKTex Refill kit for externally refillable Tensiometers T4e and T8 including hand operated vacuum pump 250 ml coated glass bottle refill syringe pipes and valves y ET BKT468 Laboratory refill kit for Tensiometers T4 T4e and T8 Incl base stand with clamps adapter that fits to T4 T6 and T8 sensor bodies 500 ml bottle pressure gauge tubes beaker refilling syringe Item Art no Refill kit for external refilling BT OK Laboratory refill kit BKT468 All vacuum glass bottles are coated and implosion proof 9 3 5 tensioLINK accessories Item Art no
11. observe rules for disposal of equipment containing electronics Riicknahme nach Elektro G Within the EU disposal through municipal waste WEEE Reg Nr DE 69093488 prohibited return electronic parts back to UMS 57 58 Your addressee at UMS 58 58
12. of 2 5 meters below the frost level i e in general 3 meters Cross shaped rods are less advisable for such low depths but this depends on soil type moisture or clay content and distance between soil surface and ground water level 43 58 Useful notes 7 Useful notes 7 1 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 The readings remain at a constant value fig 7 1 between day 10 and 16 Interpretation of readings below 15 bars and close to surface 100000 10000 1000 100 t Soil water tension _s __Tensiometer reading Soil water tension hPa 0 2 4 6 8 10 12 14 16 18 20 Time Fig 7 1 Tensiometer readings with tensions to 15 bars If the soil will get even drier and reaches 15 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 to 19 44 58 20 YEARS Useful notes UMS If there will be rain before the soils reaches 15 bars the Tensiometer cup will suck up the soil water However the soil water includes dissolved gas which will de
13. the heat flux with the internal temperature probe For a probe dipped into water the heat flux rate is lower than in air If an air bubble appears around the temperature probe the heat flux rate rises and the insufficient filling status is detected This method offers a rough but reliable reference for checking the filling and has the advantage of staying stable over the whole lifespan of the Tensiometer It replaces the previously use IR photo diode The measurement of the soil water tension is not influenced Benefits of the filling status indicator are an optimal service If for example mounting rails with integrated LEDs are used the user can check at a glance if all Tensiometers work well or which need to be refilled Also for quality assurance the status of the signal can be logged for later evaluation of the readings 2 1 6 The ceramic cup 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 T8 cup consists of 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 is at least 1500 kPa 15 bar If the soil is dryer than 1500 kPa the negative pressure inside the cup decreases and the re
14. the installation site Only for information does not influence the Tensiometer readings Ceramic Type For special ceramics for compensation of the installation angle only Compensation length Effective length of the total water column in 0 1 cm for compensation of the installation angle Data logger Interval Logging interval of the internal logger Ring buffer memory With ring buffer activated the oldest readings are overwritten when the memory space is full 29 58 T8 configuration with tensioVIEW System The Power Save Mode puts the Tensiometer to sleep when inactive Analog outputs are then switched off and the current consumption is significantly reduced If data is read out only serially or the internal data logger is used activate this option without reducing the Tensiometer operation Possibly the Tensiometer will react a little bit slower to serial commands J Sensor readings Continuous measurements Activate the quick updating of readings to receive the Tensiometer readings instantly for example during a refilling procedure Measurements are taken in intervals of 50 ms Note the rise in power consumption and that the reaction to serial commands might be slowed down The setting Measuring interval is deactivated during this mode Measuring interval This is the standard interval in which sensor measurements are refreshed and available on the analog lines 30 58 20 YEARS T8 configura
15. through the cable The membrane must always have contact to the air and should never be submersed into water Optional protective plastic tube Available as accessory Cable gland IP67 The T8 can be completely buried if required Cables and tubes of buried T8 should be protected Special cable glands are available for tight connection of a Shaft One piece shafts from 10 cm to 200 cm are available Shafts over 200 cm are divided with threaded adapter Sensor body incl electronics Direct connection between internal power converter to 6 18 VDC Pressure sensor The piezoelectric pressure sensor measures the soil water tension against atmospheric pressure 9 58 Tensiometer T8 5 Push down the shaft water retaining disk to a position directly on the soil surface 6 Slide on the thermal insulation tube over the capillary filling tubes 7 If the plug is not connected right away leave the protective cap on the plug Water tightness is only assured when the plug is kept clean 8 Connect the Tensiometer signal wires as specified see chapter Connecting the T8 The T8 can be connected to data loggers with analog input or serial RS485 or SDI12 a PC or laptop via tensioLINK bus as a standalone sensor or within a sensor network an additional 6 V Battery to run the T8 in the auto logging function internal data logger requires tensioVIEW software and USB converter for configuration the INFIELD7 f
16. time knock on cup and sensor body to loosen bubbles Degassing is complete when no air bubbles ascend from ceramic and body and the cup is completely filled with water 7 Before screwing together cup and sensor body connect the sensor to a measuring device to observe the pressure signal Destructive pressure is 3 bar Hold the cup in an upright position fill it completely and with an overlapping bulge of water Carefully and slowly screw the cup on the sensor body Allow the excess water to escape Make sure that no bubbles are enclosed 8 Fix the Tensiometer in an angle so the cup is pointing downwards and the yellow sticker on the shaft is on top 9 Degas the water in the syringe as described above and connect it to the marked refilling tube Do not bend the rubber tube Carefully press water into the refilling tube until no bubbles come out of the de airing tube Fill in at least 25 ml Check the pressure at any time 10 Remove the syringe and connect the rubber tube to the open refilling tube 5 1 3 Refilling in the field T8 Tensiometers can be refilled with the supplied 50 ml syringe through the stainless steel tubes without removing them from the soil If the refilling tubes have a total length of 5 meters or more it might be necessary to use the hand operated vacuum pump see chapter 5 1 4 36 58 20 YEARS Service and maintenance UMS With this method a measuring range of at least 80 kPa can be achieved
17. Pa 0 2 K 10 30 C 0 4 K 30 60 C 6 18 V DC 3 mA nominal max 20 mA 48 58 Appendix Optional settings Output signal ranges Temperature ranges Pressure ranges Functions Digital output Resolution Accuracies for signal range Switch Max current load Compatibility of material PH range change with tensioLINK 0 1V 0 2Vor0 5V 0 1V 0 2Vor0 5V 100 100 kPa 200 200 kPa 0 100 kPa or 10 90 kPa Filling status standard or threshold value for pressure temperature supply voltage 16 bit 0 5 mV 0 1 V 2 mV 0 2 V or 5 mV 0 5 V high resistance max burden 50 mA opened 0 V or closed supply voltage 250 mA pH 3 pH 10 avoid contact with substances that harm silicon fluoride silicon EPDM PMMA polyetherimid Sensors are delivered with standard settings unless indicated differently on the calibration certificate or delivery information 9 2 Wiring configuration 4 8x0 25 Ly Cy I Tensiometer J Ja JNSSSNSSN Fig 9 1 Tensiometer connection scheme 49 58 Appendix Configuration of T8 Tensiometer cable and plug Wiring connections Signal Wire Pin Function Vin white 1 Supply 6 18 Voc 5 GND brown 2 Supply minus 6 4 A OUT 1 green 3 Analog output 1 pressure 7 3 A OUT
18. adings go down to 0 kPa With these characteristics this material has outstanding suitability to work as the semi permeable diaphragm for Tensiometers F The cup has a lifetime guarantee against breakage 12 58 Description ofthe T8 UMS 2 2 Output signals 2 2 1 Analog The T8 version 2005 has an internal microprocessor and offers water tension and temperature as analog output signals plus the refilling status as a digital signal Water tension and temperature are available as linear voltage signals in a selectable range of 0 1 V 0 2 V default setting or 0 5 V Thus the T8 are compatible to almost any data logger or data acquisition system Furthermore the measuring range itself can be set for special measuring tasks Standard is 100 kPa to 100 kPa and 30 to 70 C The standard setting for the filling status is either switch open 0 V or closed voltage signal equal to power supply voltage 2 2 2 Digital To change the settings of signal range or use the serial interface of the T8 the tensioLINK USB converter with Windows software tensioVIEW is available as an accessory Filling status as a Digital Status If the indicator detects an air bubble the indicator switch closes and the supply voltage is available on the output If for example a LED with a series resistor is connected the LED will light up to indicate the necessity of refilling In addition or instead connect the signal to a dig
19. ctive 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 3 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 condensed water inside the cable will leave the cable through the membrane The white membrane on the cable must always have contact to air and should never be submersed into water 2 1 4 Temperature sensor A temperature probe with a tolerance of 0 2 K at 10 C is used The tip of the temperature sensor dips into the Tensiometer cup s water Thus the best possible thermal contact to the soil is achieved 11 58 Description of the T8 2 1 5 Filling status indicator The filling status indicator indicates the filling status of a T8 in a downwards installation cup lower than end of the shaft If the Tensiometer is installed in an upward angle cup higher than the end of the shaft the water will still cover the indicator even if air is already inside the cup Thus the indicator will react not before the cup is almost completely empty s fig 5 3 on page 38 The filling status is determined by measuring
20. dling 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 2 Lightning Long cables act as antennas and might conduct surge voltage in case of lightning stroke this might damage sensors and instruments og Frost Tensiometers 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 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 og Electronic installation Any electrical installations should only be executed by qualified personnel og Ceramic cup Do not touch the cup with your fingers Grease sweat or soap residues will influence the ceramic s hydrophilic performance 4 58 Tensiometer T8 UMS 1 2 Content of delivery The delivery ofa T8 includes Tensiometer calibrated and filled with 8 pin plug M12 IP67 with plug cap
21. dow threshold value 32 58 20 YEARS T8 configuration with tensioVIEW UMS Upper threshold integer Integer part of the upper window threshold Lower threshold decimal Decimal part of the lower threshold or window threshold Upper threshold decimal Decimal part of the upper threshold or window threshold Configuration example for the digital output Function of the digital output comparator Associated reading on digital output temperature Integer part of the lower threshold 24 Decimal part of the lower threshold 3 gt iftemperature is higher than 24 3 the digital output is set to 1 J Filling status testing Measuring interval Interval in which the filling status is checked with the Thermistor BDT method 33 58 Service and maintenance 5 Service and maintenance 5 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 drying out successions the T8 must be refilled The following items are required for all refilling methods Syringe with valve one supplied with each order Degassed de ionized or distilled water Measuring device for checking the pressure signal Simple method to degas water best way to degas water is by using a syringe Draw up water into the syringe until it is 2 3 filled Close the valve or block the syri
22. e smaller than the logger internal pull up resistor or at least be in a relation so the logger will recognize the zero level Please contact UMS if you have questions regarding the indicator connection 24158 20 YEARS T8 configuration with tensioVIEW UMS 4 T8 configuration with tensioVIEW 4 1 tensioLINK USB converter The power supply of the tensioLINK converter is galvanically isolated from the PC or Laptop and can be used to power connected sensors The 8 pin T8 plug has the standard tensioLINK plug configuration and can be directly connected to the converter without the need of any further items Bus distribution modules are available to link numerous sensors Any custom made cables require 4 wires for a parallel connection of all sensors If sensors should be supplied by another power source take notice to avoid potential differences This can be achieved by connecting the GND of both power sources The V line of the USB converter then is not used 4 2 Work with tensioVIEW 4 2 1 Menu tensioVIEW has a simple menu for mostly self explaining read out and configuration of tensioLINK devices After starting tensioVIEW the display is more or less blank most functions are inactivated Search devices If one or more sensors are connected via the USB converter they can be searched by pressing the magnifier button tensioVIEW offers two options for searching Single device mode tensioVIEW expect
23. elect the register Configuration for viewing and changing the programmed settings of the device Depending on the authorization status only parameters that can be edited are shown To store it in the device a changed parameter has to be sent to the device by pressing the Upload button A message notifying about the successful configuration will be displayed Configuration changes are effective immediately Tensiometers for example will re start just as ifthey were connected to power 4 3 Configuration settings for T8 Those settings which are editable only for Power users are marked with an asterisk Parameters with related functions are bundled in one folder 27158 T8 configuration with tensioVIEW UMS T8 de Eigenschaften Konfiguration Aktuelle Messwerte Gespeicherte Messdaten SE Sub Addresse 2 Gersteinformationen Bus Number 1 Datenloager System Sensor Messung analoge Ausg nge digital Ausgang Befiilttest Sub Addresse tensioLINK Subadresse Figure 4 2 Configuration menu lt M tensioLINK Bus number tensioLINK bus number of the device Sub address tensioLINK sub address of the device Explanation tensioLINK uses two types of address for each device the bus address and the sub address The reason for this is that is there might be sensors installed at the same spot but with different measuring depths for example multi level probes In this case the sub address defines
24. g tube the unmarked tube the de airing tube gt Ah 7 Syringe De airing tube Manual or other Reiling ibe vacuum pump S Mark on shaft AA Vacuum bots De airing tube with black mark Fig 5 5 Upwards installation the marked tube is the de airing tube the unmarked tube the refilling tube 39 58 Service and maintenance 5 2 Testing 5 2 1 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 us for recalibration or use the calibration accessories available from UMS 5 2 2 Check the Offset With zero pressure difference between inside and outside of the cup cup in air the signal should be 0 kPa There are two ways to check the offset 1 Connect the Tensiometer to a readout device Place the filled T8 in a beaker and fill the beaker with distilled or de ionized water to a height of 7 5 cm Wait until the reading is stable If there are bubbles inside the cup this might take a while The reading now should be 0 kPa 2 To check the zero point more precisely unscrew the cup Shake the pressure sensor to remove water from the pressure transducer hole The offset is acceptable when the reading is between 0 5 and 0 5 kPa
25. gas 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 after day 20 Interpretation of readings below 10 bars in a greater depth 10000 1000 i oO Soil water tension a Tensiometer reading oO Soil water tension hPa 1 T T T T T T 1 0 5 10 15 20 25 30 35 Time Abb 7 2 Tensiometer readings with tensions to 10 bars Other problems that can be recognized by checking the data Soil water tension 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 malfunction With T8 and T4e Tensiometers unsteady signals might also be caused by solar radiation on the refilling tubes This would require the use of thermal insulation see chapter 3 1 4 45 58 Useful notes 72 Temperature influences 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 0 to 10 kPa
26. her device is required beside tensioLINK tensioVIEW and PC to have a complete data acquisition system Readings are displayed and stored by the PC directly 2 5 Sensor logging UMS Tensiometer T8 and TS1 have an internal non volatile data memory When connected to a power supply readings of soil water tension and soil temperature are taken and stored in selectable intervals of 1 minute to 24 hours The T8 has a capacity of 4000 readings which with an interval of 1 hours is enough for 166 days of measurements In this mode of operation the power consumption is very low so modest battery capacities are sufficient even for long measuring periods To run stand alone sensors a battery box is available as an accessory The weatherproof box is fitted with a tensioLINK plug for uploading the data stored in the sensor 15 58 Installation 3 Installation 3 1 Concept planning and installation 3 1 1 Selecting the measuring site The installation spot should be representative for the soil horizon Therefore in heterogenic soils classifying drillings should be made before or during installation On farmed sites with vegetation root spreading and root growth during the measuring period must be considered Fine roots will grow around the Tensiometer cup as this is a poor but still secure source of water Therefore avoid the root zone or move the Tensiometer from time to time depending on the root growth Disturbing effects li
27. ital or analogue logger channel to record the filling status for quality control of the matrix potential readings 2 3 Serial interfaces The T8 has two serial interfaces the RS485 compatible tensioLINK interface and SDI12 13 58 Description of the T8 2 3 1 tensioLINK To use the serial interface the tensioLINK USB converter with LE RS485 allows a robust and cost effective bus linkage of sensors with cables of up to a few kilometers Data loggers with RS485 interface can directly read sensors Please contact UMS for a description of the data protocol 2 3 2 SDI12 Windows software tensioVIEW is required tensioLINK is RS485 based and used for all functions for taking online readings for uploading stored data and for configuration of the T8 Additionally a SDI12 interface is integrated for connection to SDI12 systems The SDI12 interface has to be activated via tensioVIEW Then one of the 2 analog outputs is used as the SDI12 data line 14 58 Description of the T8 UMS 2 4 Software 2 4 1 tensioVIEW The Windows software tensioVIEW supplied with the tensioLINK USB converter automatically detects all tensioLINK devices linked within a bus network The software is used for the configuration of these devices and for displaying data tensioVIEW shows for example the settings of a VS vacuum station or T8 readings from the recent days When used in a laboratory no ot
28. itions are Frost free soil Wet coarse clay or loess Low skeletal structure gravel The more gravel in a soil the more often the drilling has to be repeated to reach the required depth 3 1 7 Documentation For every measuring spot you should Measure out the position where the pressure sensor will be placed 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 the 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 see chapter 9 2 3 2 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 Therefore Tensiometers are preferably installed at an angle 18 58 20 YEARS Installation UMS 3 2 1 Vertical with downwards angle When installed from the surface an angle of 25 to 65 from the vertical is optimal for refilling In an absolutely vertical position air bubbles might inside the edges of the cup adapter Still they could be removed completely with the vacuum refilling kit BKTex In this position the refilling tube is the shorter stainless steel tube with the yellow s
29. ke waysides the rim of a field slopes or dints must be avoided or considered in the interpretation of the measuring results 3 1 2 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 7 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 obtain a differential description of the soil water situation at least 2 Tensiometers are recommended per horizon one in the upper and one in the lower level Cable lengths of 100 meters and more are possible see chapter 8 2 for cables but should be avoided for the following reasons Accuracy with a single ended connection each 10 meter of cable causes a reduction of the accuracy See chapter 3 3 1 for compensation of current drop with single ended connections 16 58 20 YEARS Installation UMS Lightning cables act as antennas and should always be as short as possible 3 1 4 Protection of refilling tubes A recent study by Prof Wolfgang Durner showed that refilling tubes must be protected from heating up and solar radiation If a bubble assembles inside a refilling tube tem
30. n mono ethylene glycol di ethylene glycol etc These could harm any of the materials destroy the ceramic cup or leak into the soil T8 Tensiometer may remain installed during the winter if the cup is positioned in a depth of at least 20 cm Then the frost will ingress the cup slowly without damaging the pressure sensor The reading will jump to a constant value After unfreezing the Tensiometer will continue to work 41 58 Protecting the measuring site 6 3 2 Emptying the T8 Also read chapter 5 1 1 Remove the connecting rubber tube from the refilling tube In a downwardly installation the refilling tube is the marked tube in an upwardly installation the refilling tube is the not marked tube 2 Connect the empty syringe to the refilling tube and completely suck out the Tensiometer water 3 Connect rubber tubes and filing tube 6 4 Lightning protection and grounding In the field measuring equipment is always susceptible to electrical surge UMS sensors and stations are protected against over voltage and false polarity as far as this is technically achievable But there never can be total lightning protection Lighting strikes are unpredictable and vary significantly with region voltage and destructiveness A proper lightning protection has to be considered whenever a system with several sensors and loggers is installed Passive lightning protection measures would comprise one or more grounding rods preferabl
31. nd 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 fulfillment 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 substantially extends the lifespan 1 6 Tensiometer T8 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 from 100 kPa water pressure to 85 kPa suction soil water tension If the soil gets drier than 85 kPa the Tensiometer runs dr
32. necessarily does not have to be degassed when a pump is used Unscrew the cup in clockwise direction and empty it N eg Do not touch the ceramic cup with your fingers Wrap a clean towel around the cup The pressure sensor diaphragm is inside the small hole on the pressure sensor body It is very sensitive and may never be touched It can be destroyed even by slightest contact No contamination should get on the sealing and gasket eg 3 Ifthe cup is dry it should be placed in a beaker filled with distilled water for several hours or overnight Initially there should be no water inside the cup Place the empty cup into the beaker in an upright position with the external water level reaching no higher than 2 3 of the cup If the cup is filled with water and water intrudes from both inside and outside cavities of air will be enclosed inside the ceramic Vacuum gauge Adaptor for OD a sensor body Adaptor for ceramic cup Connection to vacuum See PUp Fig 5 1 UMS laboratory refill kit BKT468 35 58 Service and maintenance 4 Insert the saturated but empty cup to the adapter and connect it to the degassing device Place the cup in water in an upright position 5 Fill the second UMS adapter capsule to the half with water and insert the sensor body Connect the adapter to the degassing device as well 6 Now start the vacuum pump With well saturated cups the procedure will take 1 to 2 hours From time to
33. nge with your finger Now draw up the syringe as far as possible to create a vacuum inside Rotate the syringe to create one big bubble Take of your finger or open the valve and squeeze out the bubble Repeat this procedure a few times 5 1 1 When do Tensiometers need to be refilled Tensiometers need to be refilled when the IR indicator will light up for Tensiometers installed downwardly 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 or if a lower level installed Tensiometer shows wetter readings again If the soil gets dryer than 85 kPa the readings will remain constant at the vapor 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 34 58 20 YEARS Service and maintenance UMS If the soil dries out more than 1500 kPa 15 bar the negative pressure will drop much faster as air will enter the cup 5 1 2 Refilling in the lab To reach the optimal measuring range of 90 kPa Tensiometers should be refilled in the laboratory using the refill kit 1 Set up the refilling kit and connect the vacuum pump as shown in the photo The pump should achieve at least 0 8 kPa against vacuum Use distilled or de ionized water which
34. nnection In general a data logger with differential inputs should be preferred This means both the plus signal as well as the minus signal of each sensor are measured On many data loggers less channels are required for single ended measurements which means only the plus signals are measured and related to the common sensor supply ground In this case the voltage drop depending on the current consumption and the cable resistance influences the reading and must be compensated for Example Current consumption 3 mA cable resistance 0 082 Q m for UMS standard cable and signal range 0 2 V gt Voltage drop inside a cable with length 10 m Uerror 1om cable R xX I 0 82 Q x 3 mA 2 5 mV gt Error for water tension 1 mV equal to 0 1 kPa 2 5 mV 0 25 kPa gt Error for temperature 1 C equal to 20 mV 2 50 mV 0 25 K Thus the signal is lifted for 0 25 kPa and 0 1 K per 10 m cable With the standard signal range 0 2 V the readings will be for 100 kPa 2 5 mV and 30 C 2 5 mV instead of 0 mV for 100 kPa 2002 5 mV and 70 C 2002 5 mV instead of 2000 mV 4 Change the offset correction in the data logger accordingly The signal gradient conversion factor is not changed by the voltage drop 3 5 4 Connecting the indicator Some data logger types require a pull down resistor for example 10 kOhm against ground for the indicator Pull down resistor The external pull down resistor must b
35. nst rodent bites Lead the cables through plastic pipes or use the plastic protection tubes which are available as an accessory 21 58 Installation 3 4 Offset correction for non horizontal installations The pressure transducer is calibrated without Transducer a cup Thus no compensation is required for horizontal installations If a T8 is installed in a non horizontal position the vertical water column draws on the pressure sensor and causes an offset shift u ee Compensate the offset by calculation ni by entering the installation angle in the Infield7 for spot readings in the configuration of a data logger by setting an offset by storing the installation angle directly inside the installed T8 through the tensioLINK interface The middle of the cup is regarded to be the measuring level The correction is largest for a vertical water column at 0 and varies as the cosine of the installation angle as shown on the table below In an absolutely horizontal position the offset is zero 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 Table showing the offset correction when a 5 cm column of water is tilted at various angles Angle to vertical line 0 10 15 20 25 30 Offset correction in kPa 0 5 0 49 0 48
36. or taking spot readings or downloading stored readings Please note Especially in loamy clayey soils a high pressure can occur just by inserting the T8 into the borehole Thus the pressure values should be continuously observed during installation either with the INFIELD7 handheld or online with laptop USB Converter and tensioVIEW Note for the latter that the readings are refreshed only every 5 seconds by the internal microprocessor The less air is inside the cup and the better the soil s conductivity is the faster the Tensiometer will respond to tension changes If the soil is dryer than 90 kPa it does not make sense to refill the Tensiometer The refilling procedure will be done best at the time when the Tensiometer installed in the next lower level has reached the value of drying off of the upper Tensiometer 10 58 Description ofthe T8 UMS 2 Description of the T8 2 1 T8 parts 2 1 1 Body and shaft The whole electronics are integrated in the body of the T8 The housing is made of fiberglass reinforced plastic The electronic is completely sealed and thus well protected against moisture 2 1 2 Pressure sensor 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 The non destru
37. perature changes will lead to an expansion of the air resulting in a variation of the reading Therefore refilling tubes should be as short as possible and should be thermally protected either by providing an insulating protection or by burying the tubes Thermal effect As long as the Tensiometer and its tubes are freshly and completely F filled it will work perfectly Any air trapped inside the upper parts of the tube will expand when heated up by solar energy This causes a drop of the water tension and some water will flow from the cup into the ground Thus readings will fluctuate around the actual reading during solar radiation especially with low water potentials Furthermore under permanent solar exposure the tubes get sticky and brownish Slide the supplied thermal insulation tube over the shaft end the refilling tubes and sensor cable as shown in above photo Please keep a distanz of approx 5 cm to the soil surface to avoid ant population inside the tube 17 58 Installation 3 1 5 Jacket tubes Jacket tubes are useful with shafts longer than 2 m in pebbly soils or gravel and for horizontal installations from inside a well or pit hole The jacket tube should end 30 to 50 cm away from the cup so leaking or condensation water is not conducted to the cup The inner diameter of the jacket tube should be at least 35 mm 3 1 6 Ideal conditions for installation For the installation of Tensiometers the ideal cond
38. s from soil surface Cable protection tubes Jacket tubes if required inner diameter gt 35 mm Please observe the following notes F Do not touch the cup with your fingers The ceramic should not have contact with grease or soap as this will influence the hydrophilic performance 2 Do not leave the cup in air for more than 5 minutes as Tensiometer water will evaporate and the Tensiometer will need to be refilled Procedure 1 Mark the required drilling depth on auger and Tensiometer shaft The reference point is the center of the cup Drill a hole with the desired depth on the chosen measuring spot Auger stepwise and take care when drilling the last 20 cm remove and save this soil Water will not run along the shaft if the Tensiometer is installed in an angle because the water will drain into the soil before it reaches the cup Q Read the chapter Selecting the installation position for the best installation angle 2 When using augers with a diameter of over 25 mm mix a paste of water and crumbled soil material taken out of the borehole Fill the paste into the bottom area of the borehole by using a simple pipe with outer diameter 2 cm Now take off the protective plastic cap from the Tensiometer cup w Q Important Do not turn but pull when taking the bottle off and also when putting it back on again Save the plastic bottles Do not store the Tensiometer without the protective plastic bottle since the c
39. s that only one device is connected which will be found very quick This mode is not functional if more than one device is connected Multiplex device modes tensioVIEW is able to detect up to 256 devices connected to the bus within 8 seconds but only if each device is already personalized 25 58 T8 configuration with tensioVIEW with an individual bus identification address If two or more devices have an identical address none of them will be found All devices found will be displayed in the left section as a directory tree Same types of devices will be grouped in one directory tensioVIEW Ordner f r Ger te N Typs Fig 4 1 Found devices in tensioVIEW Detected devices will be displayed with their programmed names Press the symbol to see what readings the device can offer Double click on the name to open a menu window where all specifications and functions of this device are displayed Depending on the type different registries are available The first shows an overview of the current settings and information about address number or error messages 26 58 20 YEARS T8 configuration with tensioVIEW UMS 4 2 2 Current readings Enter the interval parameters and press Start to display the current readings 4 2 3 Stored readings Open the menu Stored readings to upload the data from a T8 if logging had been activated in the logger menu 4 2 4 Configuration of a device S
40. ses the following pressure p Pa N qm 998 205 kg qqm x 9 81 m qs x 1m p 9792 39 N qm x Pa qs m qqm x m qs x m 97 92 hPa Accordingly 10 kPa at 20 C indicate a water column of 102 15 cm 8 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 47 58 Appendix 9 Appendix 9 1 Technical specifications Material and dimensions Ceramic material Ceramic dimensions Housing material Shaft material Sensor cable For shaft lengths lt 120 cm For shaft lengths gt 121 cm Plug Measuring range Pressure transducer Water tension Water level Temperature Standard output signals Pressure Temperature IR indicator Accuracy Pressure transducer Temperature probe Power supply Supply voltage Vin Current consumption AI2O3 sinter bubble point gt 15 bar Length 60 mm 24 mm PA6 GF30 Impact proof PMMA 25 mm Length 1 5 m from sensor body effective length 1 5 m minus shaft length Length 0 6 m from end of shaft Male 8 pin thread M12 IP67 100 kPa 100 kPa electronically 85 kPa 100 kPa physically 85 kPa 0 kPa Tensiometer 0 kPa 100 kPa Piezometer 30 C 70 C 0 2 V 100 kPa 100 kPa 0 2 V 30 70 C Switch open filling OK Switch closed signal Vin refilling required max burden 50 mA raw signals 0 5 k
41. tensioLINK junction box with 6 inputs for tL 8 X6 Adapter cable for connecting the tL 8 USB tL 8 4 5 to a junction box tL 8 X6 or a T piece plug tL 8 USB 9 4 Units for soil water and matriy potentials pF hPa kPa J kg Mpa bar psi rF 53 58 Appendix 1 10 1 0 001 0 01 0 1450 99 9993 2 01 100 10 0 01 0 1 1 4504 99 9926 Kt 2 53 330 33 0 033 0 33 4 9145 99 9756 Tensiometer 2 93 851 85 1 0 085 0 85 12 345 ranges 3 1 000 100 0 1 1 14 504 99 9261 4 10 000 1 000 1 10 145 04 99 2638 a paint 4 18 15 136 1 513 1 5 15 219 52 98 8977 100 000 10 000 10 100 1 450 4 92 8772 Air dry 6 1 000 000 100 000 100 1 000 14 504 47 7632 Oven dry 10 000 000 1 000 000 1 000 10 000 145 038 0 0618 standard measuring range of Tensiometers depends on air humidity Note 1 kPa corresponds to 9 81 cm water column 54 58 20 YEARS Appendix UMS 55 58 Appendix 56 58 20 YEARS Your addressee at UMS UMS Your addressee at UMS Sales Georg v Unold Tel 49 89 126652 15 Email gvu 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 D 81379 M nchen Fax 49 89 126652 20 Gmunderstr 37 email info ums muc de ce Strictly
42. the depth starting with 1 for the highest sensor Furthermore the sub address could be used to combine groups of sensors for example of one measuring site In general the required identification for a device is always the bus number If more than 32 devices are connected to the bus the sub address is counted up The allowed numbers for the bus address are 1 to 32 and for the sub address 1 to 8 28 58 20 YEARS T8 configuration with tensioVIEW UMS The default value for both bus and sub address is 0 With more than one device connected individual addresses have to be declared Serial interface activated during power down Serial reception possible in sleep mode When data are received thorough the RS485 interface the T8 is wakened With an activated reception the T8 consumes approximately an additional 0 5 mA Qi Device information Device name Individually editable name of the Tensiometer in ASCII Maximum length 12 digits Calibration date Date of the last calibration In general sensors should be recalibrated and checked after two years Installation depth Here the installation depth can be entered This is for your information only and has no further functions Installation angle Installation angle selectable from 0 to 180 If activated the water column inside the ceramic cup will be compensated in relation to the installation angel 0 means the Tensiometer is installed vertically Soil type Type of soil at
43. ticker Into this tube water is injected for refilling Before inserting the Tensiometer turn the shaft so the yellow sticker near the shaft end points upwards 2 Do not turn the shaft after it is inserted into the ground as this might loosen the cup 3 2 2 Horizontal or upwards installation angle When installed horizontally or upwards from inside a well or pit hole the shaftmark must look downwards An upward angle of approx 5 is ideal for refilling Note that now de airing and sal tube are switched the refilling tube is the longer 5x stainless steel tube without the black mark Into this tube water is injected for refilling Before inserting the Tensiometer turn the shaft so the yellow sticker near the shaft end points downwards F Do not turn the shaft after it is inserted into the ground as this might loosen the cup Note that with a horizontal installation the filling indicator will not react much later if installed upwards not before until the cup is almost empty 3 3 Installation procedure For the installation of the T8 in the field the following tools are required Tensiometer auger with diameter 25 mm ideally the UMS gouge auger with shaped blade tip Rule spirit level angle gauge marker pen 19 58 Installation Minute book camera for documentation of site and soil profile Perhaps PE plastic bags for taking soil samples from the site Thermal insulation tubes for installation
44. tion with tensioVIEW UMS A UMS T8 Eigenschaften Konfiguration Aktuelle Messwerte Gespeicherte Messdaten tensioLINK Kontinuierliche Messung off Gerateinformationen Messinterval 5s def Datenlogger serielle Schnittstelle bei Power on System Zeit bis Stromsparmodus 10s analoge Ausg nge digital Ausgang Bef ltest Kontinuierliche Messung Schelles Update der Messungen aktivieren Dies ist z B sinnvol beim Bef llen um eine schnelle Reaktion des Tensiometers zu verfolgen OK Abbrechen Hilfe Figure 4 4 Configuration menu sensor measurements J Analog Outputs DAC DACA active Turns on the analog output 1 standard use pressure DACB active Turns on the analog output 2 standard use temperature Associate reading DACA A sensor reading can be associated to analog output 1 Standard for analog output 1 is pressure Associate reading DACB A sensor reading can be associated to analog output 2 Standard for analog output 2 is temperature Associate depth DACA For multilevel probes the DACA reading can be associated to a certain depth Then tensioLINK will take readings using the same 31 58 T8 configuration with tensioVIEW bus address plus the sub address For the default value depth 1 the internal sensor readings are used Associate depth DACB Associate a depth to reading DACB DAC error output Error output value for DAC mV If an incorrect reading occurs
45. up drains fast The bottle must be filled with some water for storage 20 58 20 YEARS Installation UMS g Q 10 11 12 Connect the Tensiometer to a readout unit Check the position of the yellow sticker Carefully insert the T8 into the borehole up to the stop while continuously observing the pressure signal Using the TB25 auger you feel a light resistance at the last 6 cm indicating proper soil contact of the ceramic Do not use any force Do not hit the Tensiometer this may damage cup and pressure sensor Especially in clayey soils the pressure reading must be monitored as high pressures might build up The pressure must not exceed 200 kPa Press the soil surface with your boots gently to the shaft to close the gap Push the shaft water retaining disk down to cover the soil surface This prevents water from running down into the borehole along the shaft Leave the protective plastic cap on the plug whenever the plug is not connected Connect the signal cables as described in the chapter Connecting the T8 The Tensiometer will respond to changes in the soil water tension faster if there is no air inside the system and the soil water conductivity is high Write down the serial number position installation angle and depth Slide the supplied thermal insulation tube over the shaft end and the refilling tubes Bend the signal cable and lead it back through the thermal tube Protect the cables agai
46. urrying is unnecessary because of the accurate fitting of the Tensiometer in the soil 3 Take off the protective plastic bottle from the Tensiometer cup Tilt and pull the bottle off carefully If necessary carefully turn it counter clockwise 4 Insert the T8 into the hole to the depth mark without using force F in clayey soils a dangerous overpressure might develop Check the tensiometer s pressure reading with an Infield measuring device or a data logger Important Pay attention to the yellow sticker with the dot on the shafts top end that marks the position of the exit opening of the external filling inside the cup a Downwards installation If the position of the cup will be lower than the end of the shaft the yellow sticker must exactly face up b Upwards installation If the position of the cup will be higher than the end of the shaft the yellow sticker must exactly face down 8 58 Tensiometer T8 UMS External syringe refilling Installed T8 can be refilled or ventilated through the two capillary tubes stainless steel without being removed from the soil The tubes can be extended With the supplied refilling syringe a measuring range of at least 80 kPa can be assured With the special Refilling Kit BKT456 a range of 85 kPa can be assured Reference air pressure The reference atmospheric air pressure is conducted to the pressure transducer via the water impermeable white Teflon membrane and
47. y and must be refilled as soon as the soil is sufficiently moist again see chapter 5 1 6 58 Tensiometer T8 UMS Soil 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 7 58 Tensiometer T8 1 7 Quick start guide This chapter is only a summary of following chapters Please read the complete manual carefully before using the instrument In general the T8 is filled and ready for installation when supplied 1 Drilling the borehole Mark the required drilling depth on auger and on Tensiometer shaft Note drilling depth Installation depth cos a For installation from the soil surface an installation angle of 25 to 65 from the vertical line is ideal for the optimal removal of air from the cup fig a For horizontal installation from a manhole the borehole should point upwards in an angel of 5 fig b 2 Slurrying the cup is only recommendable in clayey soils and only if the bore hole is larger than 24 mm In coarse sand or pebbly soils fine pored slurry might create a water reservoir which slows down the response With the special Tensiometer gouge auger article no TB 25 sl
48. y with ground water contact but without an electrical connection to the measuring system With an active lightning protection each sensor and the logger are equipped with an individual grounded surge protection module Please contact UMS or your UMS dealer for assistance about integrating T8 into your measurement system 42 58 Protecting the measuring site General recommendations for lightning protection and grounding for stations with battery power First step Measure the voltage drop between sensor positions data acquisition etc to get to know the potential levels Recommendations for lightning protection on masts 2 or 3 meter masts can be equipped with a lightning rod which is installed on top of the mast and a grounding rod which is clamped to the foot of the mast This creates a certain protected space in a 45 degree angle around the tip Recommendations for lightning protection of enclosures Surge protection devices are installed in one corner inside the measuring enclosure All lines to and from the surge protection devices should not run parallel System protection of stations with enclosure and mast Lines to equalize drops in the electrical potential between mast and grounding rod are installed 50 cm below the soil surface Lightning protection with grounding rods According to the standards the ground rod diam 25 mm must be inserted into the ground for a minimum
49. yellow 4 Analog minus gt 1 digital grey 5 Filling status max supply Soi A i OUT voltage some loggers need a eer ping voltage divider RS485 A pink 6 RS485 A 2 wire RS485 B blue 7 RS485 B 2 wire A OUT 2 red 8 Analog output 2 temperature SDI12 or SDI12 Configuration of the USB converter USB converter plug configuration Signal Pin Function Vout 1 Supply 7 10 Voc GND 2 Supply minus n c 3 n c 4 n c 5 RS485 A 6 RS485 A 2 wire RS485 B 7 RS485 B 2 wire n c 8 8 pin female plug 50 58 20 YEARS Appendix UMS 9 3 Accessories 9 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 Item Art no 1 8 pin connection cable for T8 nn Length 1 5 m CC 8 1 5 Length 10 m EC 8 10 z Additional items na AE NO een Clip on cable markers 30 times numbers 0 9 KMT Plastic protection tube for cables are available with several diameters also dividable slotted tubes for easy re fitting 51 58 Appendix 9 3 2 Handheld measuring device Infield7 handheld measuring device

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