D6_Datasheet
D6
Tree growth-sensor strain gage clip sensor
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Continuous high-resolution measuring of circumferential variation of trees
Easy mounting without damage of the bark or disturbance of growth
Measuring of daily changes and immediate reaction with an accuracy of 5 µm
Minimisation of the cables friction on the bark and dependence on temperature
Measuring range easily expandable by adjusting of the cable
Circumferential
Measuring Cable
with Teflon layer
Tree
Data transmission
Clip-Sensor
Fig 1: Principle of measurement
Function: The trees dimensional changes are
conveyed to the clip by a cable tied around the
trunk and are transformed into a corresponding
resistance change in strain gages, which are fixed
on top and bottom of the clip, wired into a full
Wheatstone bridge.
The cable's dependence on temperature is
extremely low (1 ppm).
A special Teflon-layer is placed between cable
and bark to reduce the friction of the cable and to
protect it from icing, resin or callousing.
The Strain-Gage Clip-Sensor is designed for
continuous high-resolution and automated
measuring of circumferential variation of trees.
Small in dimension and weight, the clip-sensor
can easily be fixed on the trunk without any
damage to the bark or disturbance of growth.
The complete sensor device is tightened like a
belt and kept in position by a spring. Variations in
tree dimensions are conducted directly to the
sensor for recording the trees immediate
reactions to environmental influences, swelling of
the bark, level in water conduits or cell division.
Clip-sensor
Data transmission
Teflon-pad
Measuring cable
Teflon-net
Tree
Fig. 2: Schematic view
The following diagrams show the results of measuring the circumferential variations of a fir tree. The
daily changes are registered very precisely. The trees reactions are explained by the daily weather
conditions which were recorded simultaneously.
Fig. 3:
Circumferential
variations* of a fir
tree: Largest
circumference at
sun rise during dry
period between
Aug. 3rd and 6th;
circumferential
increase with
rainfall starting on
Aug 7.
Time:
1,8
0:00
0:00
0:00
0:00
0:00
0:00
0:00
0:00
0:00
0:00
Circumferential
variation
(mm)
1,6
1,4
1,2
1,0
0,8
0,6
Date:
Fig.4:
Recording* of
circumferential
variation between
August and
October 1995.
3.8.
4.8.
5.8.
6.8.
7.8.
8.8.
9.8.
10.8.
11.8.
12.8.
Circumferential variation (mm)
2,4
2,2
2,0
1,8
1,6
1,4
1,2
1,0
(* Data acquisition
every 30 minutes)
0,8
0,6
Date:
14.8.
28.8.
14.9.
28.9.
14.10.
Art. No. D6
Sensor
Measuring range
Power supply
Signal full-bridge
Signal characteristic
Range of signal
4-wire full-bridge strain gages
50 mm circumf. growth without adjustment
UDC = 5...15 VDC
USig = UDC * k * εDMS = UDC * L * ü'
∆USig / ∆L = -0,12 mV/mm * UDC/V
USig » 9 mV ... 0.8 mV * UDC/V
Bridge-resistance
Linearity
Accuracy
Max. current
350 Ω
±1%
5 µm
50 mA
The measuring cable is made of INVAR-steel, having
an extremely low dependence on temperature (<1
µm/mK) and a very high resistance against corrosion.
The strain-gages are covered with rubber polymer
(IP67).
© 2001 by UMS GmbH
Technische changes reserved ·Version August 2001
Technical Specifications
28.10.
Power supply voltage
Signal voltage
Strain gage value (k = 2,1)
L
∆L
ü'
Strain gage tension
Distance between clip’s ends
Cirumferential variation
Clip’s transforming value
εDMS
Weight
Embracing tension
Temperature range
Dependence on temp.
<20 g
<5 N
-30°C ... +50°C
<4 µm/K
The clip-sensor can be used under atmospheric
conditions (Rain, temperature -25 to +35°C). The fullbridge is temperature compensated.
Product
Info
Umweltanalytische Meß-Systeme · www.ums-muc.de
UDC
USig
k
Dipl.-Ing. Martin Naleppa
Tel. +49 (0) 89 / 12 66 52 - 14 · Fax - 20
eMail: mn@ums-muc.de
UMS GmbH · D-81379 München · Gmunder Straße 37
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