Probes from Keller AG für Druckmesstechnik are designed to monitor groundwater levels and filling levels in tanks, and can be used in a wide range of conditions.
Depending on requirements, these probes provide fully autonomous operation or they can be used with an integrated data logger, wireless transmission (GSM), an ambient pressure-compensating capillary or a separate absolute pressure sensor. Depending on the sounding tube, Keller offers probe diameters of 16mm and 18mm up to 22mm.
Thanks to its diameter of only 16mm, the DCX-16 can be used in space constrained locations. The pressure sensor is welded into the logger housing. Type DCX-16, which is screwed in position and fully watertight, operates as an autonomous battery-powered data collector with an absolute pressure sensor.
In shallow water, a second logger can be used for separate recording of the barometric pressure on the surface. The differential pressure or the filling level is then calculated in the PC by subtraction of the time-stamped measurement data from the individual loggers. Version DCX-16 SG/VG provides a cable connection, wherein barometric pressure is fed to the sensor as a reference, via a pressure-compensating capillary in the connecting cable. There is no need to remove these loggers from the sounding tube in order to read the data. The interface plug is secured on the sounding tube with a fixing device.
The fully-welded DCX-18 featuring a diameter of 18mm is designed as an autonomous level logger for low-cost, long-term measurements of level and temperature, with rechargeable accumulator-type batteries. The microprocessor electronics compensate for linearity and temperature deviations by the pressure sensor, achieving a further increase in the accuracy of the pressure and temperature signals. Different operating modes, with an absolute pressure sensor or an overpressure sensor with a pressure-compensating capillary, can also be supplied for the DCX-18. The measurement data is stored in a non-volatile memory. The batteries are fast-charged every time data is extracted via the charging/read-out plug.
Type DCX-22 AA level loggers 22mm in diameter, register and compensate for fluctuations in the local barometric pressure with a watertight air pressure sensor that is fitted on the top end of the sounding tube. These devices are resistant to conditions of use in a damp environment, and will not even be damaged by brief flooding. The efficient electronic equipment registers the signals from the high-precision pressure and temperature sensors, corrects linearity or temperature deviations according to a mathematical model, and then records the values to the internal memory. For standard operation, the built-in battery has a lifetime of 10 years.
The user-friendly DCX can be adapted to the specific requirements of the measuring point so that only useful data is stored. The recording interval can be event-controlled, and installation data and comments on the measuring point can also be stored in the probe.
For sounding tube diameters of 2” or more, the data loggers can operate in conjunction with a screw-on remote mobile wireless data transmission unit (GSM).
GSM-2 DataManager, the flexible, user-friendly software available free of charge, performs the key functions of a monitoring, collecting, controlling and organising unit in the central PC. Virtually every aspect of configuration and monitoring of the DCX data loggers with the GSM-2 module can be handled via the GSM-2 DataManager software or via email.