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The instrument operates with backscatter infrared sensors embedded in a stainless steel rod (titanium). The sensors are placed on an
active board at a distance of 10 mm. This means that 100 sensors are mounted per meter, this correspond to the resolution of this measuring device.
Each sensor consists of an infrared transmitter and detector. The sample to be taken has a volume of approx. 10 cm³ at a distance up
to 100 mm in front of the sensor.
Optical filters prevent interference by other light sources. This makes the instrument suitable for locations like tidal areas with
dry periods.
The instrument contains three additional sensors.
- An inclinometer for two directions will give the actual angle between ground and instrument. The maximum range is 60° in all directions.
- A pressure gauge senses the actual depth of the location of the instrument and it gives information about tides.
- A temperature sensor detects the temperature of the steel housing which is related to the water temperature.
Activation and power supply for the sensors as well as for the transmission of the signals are controlled by a battery powered central
unit sealed-in the head of the instrument. It consists of a microprocessor, a data memory, the additional sensors and the energy supply.
The energy consumption of the instrument is very low ( < 6 mAs). That means one 9V block alkaline battery will provide the
necessary energy for 2 months, assuming a sample rate of 10 measurements every 5 minutes, or the energy for a standby status of approx. 6 months. The capacity of 8 Mb
will provide a measuring time of approx. 8 weeks in total, without weakening the battery.
The microprocessor carries out all of the tasks necessary for control. Incoming data is processed by the microprocessor and stored in
memory.
The ASMA 3.11 software runs on Pentium III PC’s WIN9x, 2k, XP-prof. and XP-home.
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