Field Tensiometer from UMS by Team Medical & Scientific Sdn. Bhd. Email : info@tms-lab.com

1. Tensiometry for the 21st
Century: Principles,
Innovations Field and
Applications
Georg von Unold
TMS – Seminar 2013

3. Sole Distributor : Team Medical & Scientific Sdn. Bhd.
Tel : 03-5122 5108
Email : info@tms-lab.com

4. • Water in soils, as well as on the surface will always move from areas of higher
potential to areas of lower potential.
Some Background on tensiometers
TMS – Seminar 2013

5. Content
 Some background on tensiometers
 How do tensiometers work
 Assembly of tensiometers
 Types of tensiometer
 T4
 T4e
 T8
 TS1
 T5
 T5x
 Refill kits (T4, T8)
 Data collection
TMS – Seminar 2013

6. Soil specific Relation
Potential to Water Content
TMS – Seminar 2013

7. Tensiometer range
10.05.2013 TMS – Seminar 2013

8. Sensors & applications
10.05.2013 TMS – Seminar 2013

9. Assembly of a tensiometer
Reference air
pressure
High grade ceramic cup
Filled with degassed water.
Pressure sensor
Sensor body incl
electronics (T8)
Shaft
Refilling tube
Temperature sensor
(T8)
TMS – Seminar 2013

10. How do tensiometers work?
Soil water and Tensiometer water have
contact through a porous ceramic A wetted
porous ceramic creates an ideal pore/water
interface. The ceramic is permeable for
water, but not for air up to 15 bars tension.
So we can measure tension.
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.
TMS – Seminar 2013

11. The T4/T4e Tensiometer
 The T4/T4e Precision tensiometer is made for outdoor
monitoring projects
 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
dry and must be refilled as soon as the soil is sufficiently
moist again.
 The T4 is available in 2 versions: the standard T4 without
refilling tubes, and the T4e with refilling tubes for
refilling the Tensiometer with a syringe.
Types of tensiometer
TMS – Seminar 2013

12. The T4/T4e Tensiometer
Measures +100 kPa ... -85 kPa
Bridge Signal: +100 mV ... -85mV
Types of tensiometer
Applications
Field measurements
Water balance, leaching, transport studies
Ecological impact studies , model calibration
Agricultural or forest studies
In-situ retention curves
Data logger applications
Spot readings with the INFIELD7b
Benefits
Reliable outdoor tensiometer
Solid construction
Installation in any orientation
Year-round operation deeper than 30 cm
Limits
Will not work in dry or frozen soils
TMS – Seminar 2013

13. T4 Tensiometer refilling
 To assure rapid and reliable measurement of the soil
water tension, the cup must be filled, bubble-free, with
degassed water. After dry periods or periods with wet
and dry cycles, the T4 or T4e 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
Types of tensiometer
TMS – Seminar 2013

14. The T4-e Tensiometer refilling
 The T4e is equipped with 2 stainless-steel capillary tubes
which lead through the cable gland and the shaft. Each
one has an opening that ends inside the ceramic cup.
 The main advantage of the T4e is:
it allows easy refilling of the T4e while it remains
installed in the ground.
 Tube 1 ends at the very tip of the cup, tube 2 ends next
to the pressure transducer opening. Outside, both tubes
are connected with a short rubber tube.
 Any air bubbles will ascend and accumulate either in the
ceramic’s tip around tube 1 (upwards installation angle)
or next to opening 2 (downwards installation angle).
Accordingly the air is removed either through tube 1 or 2
Types of tensiometer
TMS – Seminar 2013

15. The T8 Tensiometer
 The T8 is ideally suited for long term monitoring projects.
 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 dry and
must be refilled as soon as the soil is sufficiently moist again
(syringe refill unit)
 The electronics are integrated in the body of the T8. The
housing is made of fiberglass reinforced plastic. The electronics
are completely sealed and thus well protected against moisture.
 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.
 To change the signal range settings or use the serial interface of
the T8, use the tensioLINK® USB converter and Windows
tensioVIEW® software
Types of tensiometer
TMS – Seminar 2013

16. The T8 Tensiometer
Measures +100 kPa ... -85 kPa
Signals: configurable Interfaces:
tensioLINK, SDI12
Types of tensiometer
Applications
Field measurements
Water balance, leaching, transport
studies, model calibration
Agricultural or forest studies
In-situ retention curves
Data logger applications
Spot readings with the INFIELD7b
Benefits
Integrated amplifier
Integrated soil temperature sensor
Integrated fill level indicator
Integrated external refilling: Solid construction
Limits
Will not work in dry or frozen soils
TMS – Seminar 2013

17. T8 Tensiometer refilling
 To assure a rapid and reliable measurement of the soil
water tension, the cup must be filled, bubble-free, with
degassed water. After dry periods or periods with wet
and dry cycles, 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
The refilling procedure is similar as for the T4e
Types of tensiometer
TMS – Seminar 2013

18. TS1 Tensiometer
 The TS1 has a self refilling multipurpose tensiometer
with an internal computer controlled pump for long
term monitoring projects
 These tensiometers work from +100 kPa (water
pressure) to -85 kPa (suction / soil water tension).
 The TS1 combines the principles of a pressure
transducer Tensiometer to measure the soil water
tension and a pore water sampler that extracts soil
solution through a porous ceramic: inside the TS1 a
bidirectional miniature pump is integrated between
pressure transducer and ceramic cup. A
microcontroller controls the functions of pump and
sensors. To refill the cup a negative pressure, lower
than the water tension in the surrounding soil is
established to draw water into the ceramic cup. Excess
water is released through an exhaust back into the soil.
Types of tensiometer
TMS – Seminar 2013

19. TS1 design
TMS – Seminar 2013

20. TS1 Tensiometer
Measures 100 kPa ..-85 kPa
Signals: configurable
Interfaces: tensioLINK, SDI12
Limits
Does not measure when soil
is dry or frozen
Types of tensiometer
Applications
Field measurements of pF/wc
Ecological impact studies
Agricultural studies
Model calibration
Long time monitoring studies
Water balance and transport studies
Benefits
Automatic self-refilling and deaerating
Continuous fill level controlling
Optional pore water sampling
Automatic emptying before frost
Integrated soil temperature probe
Auto logging function
tensioLINK and RS485 interface
Low maintenance
TMS – Seminar 2013

21. T5 Tensiometer
 These Tensiometers work from +100 kPa (water
pressure/level) to -85 kPa (suction/soil water
tension)
 The T5x, with extended range goes to a lower
tension of at least -200kPa.
 The T5 Miniature Tensiometer is especially
designed for point 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 cm2 and a
diameter of 5 mm the ceramic tip has all
advantages of small dimensions: little soil
disturbance, point pick-up and fast response.
TMS – Seminar 2013

22. T5 Tensiometer
Measures +100 kPa ...-85 kPa
Bridge Signal +100 mV ... -85 mV
Limits
Types of tensiometer
Applications
Point measurement of water potential
Miniature lysimeter studies
Lab determination of pF/wc and K/Psi
Benefits
Accurate zero-tension reading
Fast response: With sufficient filling
the T5 responds within 5 seconds
to an applied air pressure change
of 0 to 85 kPa
Most standard T5 reach a range of
at least 150 kPa when delivered.
Limits
Not for dry soils, not frost resistant
In the field applications require
impact protection
TMS – Seminar 2013

23. T5x Tensiometer with extended range
 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.
 The T5x often goes to -250 kPa before running empty, and 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 an effect called boiling retardation, the
special ceramic with smaller pores and, as a necessary condition, an
absolutely gas free filling.
Types of tensiometer
300
200
85
tension [kPa]
time
measuringrange
bestpossibleT5xStandard
T5 reading
range
TMS – Seminar 2013

24. The T5/T5x Tensiometer refilling
 To assure a rapid and reliable
measurement of the soil
water tension, the cup must
be filled, bubble-free, with
degassed water. After drying
cycles the T5 must be refilled
with the T5-set.
Types of tensiometer
TMS – Seminar 2013

25. T5/T5x Tensiometer refilling
 It is easy to refill the T5 without
any vacuum pump with the T5-
Set with several syringes.
 Checking the refilling status, the
refilling procedure itself and the
response after refilling with the
handheld unit INFIELD
Types of tensiometer
TMS – Seminar 2013

26. T5/T5x Tensiometer refilling
 Refilling the cup with
degassed water
Types of tensiometer
 Refilling the body with
degassed water
TMS – Seminar 2013

27. Refill kits
Refill kits for T4/T4e and T8
The following requirements are obligatory:
 Deionized water
 Degased water
 INFIELD 7 Handheld to control the refiling process
For laboratory refilling we recommend our BKT456 Refill kit
For field applications we recommend the BKTex or a simple syringe kit
TMS – Seminar 2013

28. Reading and Data Logging
Infield 7
 The INFIELD7, is a multi-functional handheld
read-out unit for Tensiometers and other soil probes.
 The following probe types can be connected:
UMS Tensiometers T1, T3, T4, T5, T8 and TS1
SIS smart gypsum block
Watermark and Soilmoisture gypsum block
FD Thetaprobe ML2x
FD Echoprobe
Temperature probes
Advantages
 Memory for 250 readings
 Vertical water column compensation for Tensiometers
 T8 and TS1 configuration
 Download readings to PC with accessory USB-connector cable
 Firmware capable for upgrades
TMS – Seminar 2013

29. Logger & tensioLink -
application
TMS – Seminar 2013

30. tensioView
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31. tensioLink
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32. Thank you!
10.05.2013 TMS – Seminar 2013