ST01
Soil
Temperature Sensor
ST01 is a high quality temperature sensor that is
specifically designed for soil temperature measurement in extreme
environments. Using top quality materials it is suitable for hostile
conditions as encountered in outdoor installation (temperature, radiation,
chemicals). It is designed to have a record-breaking lifetime with optimal
stability. Employing a platinum sensor, at extreme temperatures a higher
accuracy can be attained than with commonly used thermistors.
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Figure 1 ST01 Soil Temperature
Sensor: The sensor consists of a stainless steel needle (1) with a
temperature sensor (2) (normally Pt100, also Pt500 and Pt1000 available).
The Pt elements are connected in a 4-wire configuration. The Teflon
cabling (3) is welded (4) to the stainless steel. All dimensions are in
mm.
INTRODUCTION
The measurement of soil
temperature is recommended by the World Meteorological Organisation at
depths of 5, 10, 20, 50 and 100 cm.
Proper installation of soil
temperature sensors requires a lot of effort. Once installed, sensors are
usually left alone without calibration for a long time. This means that
the sensor and cabling should be very reliable and stable over time.
ST01 is
designed to be an ultra-stable sensor that can withstand the extreme
conditions met in meteorological use; partially sub-soil, partially
above-soil installation.
ST01 DESIGN
The ST01 cable as well as the
sensor itself can be used across a very wide temperature range. The usual
weak points of cabling have been eliminated; ST01 has a high resistance to
the combination of high moisture & radiation and does not crack when
bended at low temperatures. The needle and cable are resistant to
virtually all chemicals, oils and fluids. The preference for Pt elements
is because of their excellent stability (as opposed to thermistors that
are known to behave unstably in case of thermal shock and exposure to
temperatures higher than 80 degrees). Also the linearity of the Pt
elements is such that the initial acuracy at extreme temperatures is much
better than that of thermistor based sensors; + / - 0.25
°C
between -50 and +50
°C.
A one-point calibration in ice is usually
sufficient as general quality assurance and to increase the accuracy to
+/- 0.15
°C.
SUGGESTED
USE
MORE INFORMATION / OPTIONS
- Alternative designs:
Alternative models are manufactured on request. See
also model STP01.
- Cable extension:
ST01 can be ordered with extended cable. Delivery times are significantly
longer than with standard cable length.
- Manual: free of
charge as a PDF file via e-mail.
ST01 SPECIFICATIONS
-
Standard sensor: Pt100, IEC 751:1983
class A
-
Alternative sensors: Pt500, Pt1000
-
Measurement range:
-60 to +150 oC,
cable remaining flexible
-
Attainable
accuracy: + / - 0.25
°C,
+ / - 0.15
°C with
individual calibration (both across -50 to +50
°C)
-
Moisture protection needle
-
and cable until wiring exit: IP 68
-
Pressure resistance: 6 bar
-
UV resistance: no UV degradation
-
Standard cable
length: 3m
-
Expected lifetime: >10 yrs (normal
field conditions)
-
Cable
material: extruded Teflon
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