The Gealog GSM Datalogger is a battery driven datalogger-system with integrated GSM-modem.

The datalogger normally transmits the stored data 1x or 2x per day to the network centre. The measuring system is designed for extremely low power consumption. With one battery pack a standard groundwater level measuring station can be operated up to 18 months. Because of the special mechanical construction the whole datalogger can be flooded up to 3 meters without any damage.

The measuring system can be installed into groundwater pipes starting with diameter of 4 inches. To allow for the transmission of the GSM-radio signal plastic pipe-caps have to be used or also Aluminium caps with a plastic element inserted into the Aluminium. Due to this layout of the measuring station nothing of the measuring system is to be seen from outside resulting in an optimal protection against theft and vandalism.

Measuring with an electric light water level gauge can be performed without removing the datalogger.

Measuring parameters/precision

• Water level:
  - Sensor element: State of the art piezo resistive silicon cell
  - Silicon oil filling between membrane and sensor element.
  - Sensor resistors on ceramic substrate.
  - Temperature compensated
  - Sensor membrane made of stainless steel
  - Capillary tube for air pressure compensation
• Measuring ranges: 70 cm, 3 m, 10 m, 20 m, 30 m or 70 m
  - Please select the necessary measuring range which corresponds to the expected maximum
  variations of the water level at the measuring site.
  - Resolution: 12 Bit
  - Linearity error: ± 0.1% full scale
• Tolerable overpressure: 3 x measuring range or 8 bar
  - Long term stability better than 0.1%/ year
• Water temperature:
  - Sensor element: NTC-thermistor
  - Measuring range: -5°C up to 45°C
  - Uncertainty: 0.2°C