The incremental shaft-encoder measures water-level when fitted with a pulley-wheel which rotates with water-level changes when driven by a float and counterweight mechanism connected to the pulley via a wire.

When used in conjunction with Isodaq data loggers, the unit is pulsed powered providing accurate water level measurement with minimum battery power consumption. When installed in a suitable diameter stilling-well high measurement accuracy can be achieved to an overall accuracy of better than +/-2 mm with a resolution of 1mm.  
 

These shaft-encoders are suitable for water-level measurement over relatively small operational range, typically of less than 10 metres, due to the need to set-up a careful balance between the float and counterweight.

The sensor is connected to either Isodaq VF series data loggers or the Hawk XT telemetry logger via a C21 plug-in sensor card adaptor which conditions the output signal for the pulsed output from the encoder device.

The Shaft-encoder is well-proven in streamflow gauging and flood warning stations in the UK with thousands installed for the Environment Agency and SEPA.

Sensor card for Isodaq loggers – C21

The sensor card is required for all VF series loggers and for the Hawk XT series telemetry logger.  
 
It is not possible to use this instrument with the new ruggedised Hawk RT GSM logger.