Umwelt-Geräte-Technik GmbH
| Eberswalder Str. 58 | D-15374 Müncheberg | phone: +49 (0) 33 43 2 - 89 575 |
5.2.
Transformation digital signal in measurement value
The Full Range Tensiometer provides a digital output signal for the temperature and pressure readings.
The transformation of the digital signal in a measurement value is shown below (equation 3 and 4).
The conversion into the measured soil tension has to be done by using equations 1 and 2 (see chapter
3.2. or calibration certificate).
Conversion of the digital output into a measurement signal:
The Full Range Tensiometer sends a six-digit number in the range of 000000 to 065536. Those are
converted as follows:
Temperature:
The measurement range of the temperature sensor installed in the Full Range Tensiometer is limited
to -40 °C to +60 °C. However, the digital version of the Full Range Tensiometer is able to display
temperature values between - 327.68 °C and +327.67 °C with a step size of 0.01 °C. The temperature
value is obtained from the digital number by the following equation:
𝑇
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
=
𝑑𝑖𝑔.𝑜𝑢𝑡𝑝𝑢𝑡 𝑣𝑎𝑙𝑢𝑒−32768
100
(3)
T
current
: current measured temperature value
dig. output value:
raw value of measurement channel
32768:
calibration constant
Note, that the measurement range of the temperature sensor limits the measurement range of the Full
Range Tensiometer.
Pressure:
The digital version of the Full Range Tensiometer is able to display pressure values between - 100.0kPa
to +3176.8 kPa with a step size of 0.05 kPa. However, the measurement range of the pressure transducer
is limited to -100 kPa and the customizable upper limit, e.g. 500 or 1500 kPa (TYPE 5D or TYPE 15D). For
specifications see the included calibration certificate. The pressure value is obtained from the digital
output by the following equation:
𝑃
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
= (
(𝑑𝑖𝑔.𝑜𝑢𝑡𝑝𝑢𝑡 𝑣𝑎𝑙𝑢𝑒−16384)∙31
32768
− 1) ∙ 100
(4)
