WATER & SOIL

|

|S

Mini

Tensio-

meters

Small design allows insertion

|Sinto soil without damaging nearby plant roots Ideal for irrigation

|Smanagement of glasshouse crops

Small design suitable for use

|Sin plant pots and grow bags Suitable for soil, peat and

|Sother mediums

No correction factors for

|Sdifferent soils or mediums The Mini Tensiometer is a small need to exert a suction to suction inside the instrument version of Skye’s successful remove water from the soil, it is equilibrates with the soil field tensiometer range.

this suction which is measured suction. The suction (or Tensiometers measure the by the tensiometers.

negative pressure) is measured water availability to plant roots, by the electronic pressure and so can be used in irrigation The tensiometer itself consists transducer fitted into the top.

scheduling and crop of a shaft of clear acrylic plastic management.

(length variable depending on The tensiometer pressure depth of measurement reading can be displayed and The Mini Tensiometer version is required), with a porous monitored using the suitable for installing in plant ceramic bulb at the lower end.

HydrSSense logging meter, as pots, containers or grow bag The top is sealed with a rubber shown above, or can be systems. Its small size stopper, and fitted with an automatically recorded using a minimises intrusion and root electronic pressure transducer.

Skye DataHog datalogger. The disturbance.

DataHog system can also be This shaft is totally filled with used for switching on automatic Tensiometers are designed to water before installation into the irrigation systems if required.

be permanently installed in the growing medium to be growing medium, which they measured. The water is able to equilibrate with and measure flow in or out of the tensiometer the ‘soil suction’. Plant roots via the ceramic bulb, as the





SPECIFICATIONS

Shaft dimensions

Shaft construction Electronics dimensions Electronics construction Weight

13.5mm

Porous ceramic

Material

21mm

20 to 50g

bulb.

Dupont

Clear acrylic shaft

‘Delrin’

th le

lengths 10cm to

m

g

b

m

able

C

ne ria

50cm. Rubber

5

L

a

3

v

septum stopper

mm52

Cable length

Excitation voltage (2) Sensor excitation current Typical output (1) Linearity & hysterisis error

Screened cable.

5 to 10 volts

1.25 mA at

0-50mV D.C. at

Typ. < 0.1%

3m. standard.

5 volts

5 volts excitation Longer if required Thermal error

Null offset shift Long-term stability Operating range

Measurement range of span

Typ. < 0.4%

Typ. < 0.2mV

0.1% per

0 to +70°C

0 - 850 hPa (0-

0 to 50°C

0 to 50°C

year typ.

(precautions

850mbar) (minus

required for

shaft length - i.e. for operation in below 30cm shaft length zero conditions)

the range is 0-820

hPa)

NOTES ON SPECIFICATIONS

(1) The output is ratiometric for excitation voltage, but is usually calibrated at 5 volts. The transducer behaves as a 'bridge' type sensor and is suitable for connection to any meter or logger with differential inputs. DataHogs and the HydroSense are designed for these sensors (2) Tensiometers require a stabilised power supply which is provided by the DataHog datalogger and HydroSense meter. Other dataloggers may not give a stabilised power supply. In this instance, an optional stabilised power supply can be built into the tensiometer.

ORDERING INFORMATION

Sensor

SKTM 600 series

Mini electronic tensiometer.

Please state shaft length required Skye Instruments Ltd 21, Ddole Enterprise Park SKTM 690

Replacement ceramic bulb and shaft.

Llandrindod Wells Please state shaftlength required Powys LD1 6DF

United Kingdom

/S

Stabilised power supply for electronic tensiometers Meters & datalogger TEL +44 (0)1597 824811

SKT 660

HydroSense logging meter FAX +44 (0)1597 824812

EMAIL skyemail@skyeinstruments.com SDL 5000 series

DataHog datalogger WEB http://www.skyeinstruments.com Recommended Accessories TEN/5

Syringe and filling tube -

recommended for filling and installing all tensiometers





Document Outline


Page 1

Page 2