The water level instrument is normally connected to the surface of the water by a float system. As the water level changes, the input shaft rotates. An optical encoder is mounted on the input shaft. On installation, the instrument is set to display the water level. The encoder is continuously monitored as the instrument tracks water level changes. These changes update the LCD display and the readings can be recorded by an associated datalogger.
The very low mechanical friction and inertia of the instrument mean that it can produce data with high precision and accuracy. A replaceable battery pack powers the instrument for more than twelve months. Practical design and rugged construction ensure easy operation and long service life.

The 6547 radar water level sensor is 4-20mA two-wire instrument that provides continuous water level measurement of water in rivers, streams, open wastewater channels, stormwater overflow tanks and pump stations. The 6547 is a radar sensor which provides accurate long term measurements of water level up to 8m range from the sensor.

The radar sensor emits extremely short microwave pulses through the antenna. The emitted signal is reflected by the medium/water and then received as an echo by the antenna. The time between the emitted and received signal is proportional to the distance and is outputted as the measured value. The sensor is normally mounted vertically with a bracket mounted on a structure with the sensor pointing downwards. The 6547 is almost maintenance-free due to non-contact measuring principle and is protected by an IP 68 housing.

The radar SDI-12 version 6547S that provides accurate long term measurements of water level up to 15m range from the sensor is available as well.

Radar readings are unaffected by the change in temperature and pressure making this instrument ideal for use in difficult process conditions.

When used with a companion Unidata IP data logger, collected data is transmitter to a central Neon server where data can be viewed on the Neon Web server in near real time from any browser. Same data can be reported to other systems using email, ftp, and web services.