SLD – Side Looking Doppler Sensor
Water flow meter for longterm data collection of velocity and discharge measurements
The OTT SLD is a measurement system for continuous measurement of water velocity and level in streams, rivers, and canals. The sensor employs the acoustic Doppler principle to reliably measure flow velocity in a variety of naturally occurring conditions, including during most flood events.
- Fixed installation
- Flow velocity
- Side-Looking-Doppler for continuous discharge measurement in rivers and open channels. Discharge calculation based on velocity – index – method. Integrated vessel filter algorithm, Modbus interface and output of total volume of flow (max. interval 1 day).
- ± 10 m/s
- ± 1 % of measured value ± 0.5 cm/s
- Equipped with two horizontal ultrasonic transducers “looking sideways” into the flow (Side Looking Doppler) to measure water velocity.
- An optional vertical transducer and integrated pressure cell measures the water level.
- All measurement values are analyzed, verified and processed by an integrated signal processor, before being used in the calculation of discharge.
- Velocity measurements from up to nine cells are used, along with measured water level, to calculate discharge either internally in the OTT SLD or externally in a data logger.
- All measurements can be retrieved using SDI-12, RS485 , RS232 or Modbus RTU protocols and are available for storing in a data collection platform, such as the OTT netDL station manager.
|Flow velocity measurement|
|Measuring range||±10 m/s|
|Accuracy||1% of measured value ± 5 mm/s|
|Number of measuring cells||9|
|Cell size / Blanking|
|600 kHz||2 … 10 m / 0.5 … 30 m|
|1.0 MHz||1 … 4 m / 0.3 … 15 m|
|2.0 MHz||0.2 … 2 m / 0.1 … 8 m|
|Beam angle / Max. profiling range*|
|600 kHz||2.4° / 80 m|
|1.0 MHz||2.4° / 25 m|
|2.0 MHz||2.1° / 10 m|
|Minimum coverage||0.15 m (water level option)|
|Supply voltage||12 … 16 V DC, typ. 12 V|
|Power consumption||50 … 500 mW, depending on measurement cycle|
|Water level measurement|
|Measuring range||0.15 … 10 m|
|Accuracy||±3 mm, depending on stratification|
|Pressure cell (optional)|
|Measuring range||0 … 10 m|
|Accuracy||±0.25 % FS|
|Interfaces||RS-232, SDI-12 or SDI-12 via RS-485, Modbus (optional)|
|Operating temperature||-5 … + 35 °C|
|Storage temperature||-20 … +70 °C|
|Length x Ø||45 … 52.2 cm x 7.5 cm|
|Wall bracket (accessory)|
|Components||Bracket, protective cover, and C rail mount|
|Discharge calculation||Within the unit or externally on a datalogger, e.g. OTT netDL|
|OTT SLD EasyUse Installation and service software||System setup, commissioning, reviewing and optimizing|
|OTT Prodis 2 (accessory) Calibration software||Determining correction factors, (velocity-index method and others), optimizing discharge calculation, managing stations|
|*The beam angle is understood to be the measured angle with regard to the main axis. The maximum profiling range depends on the water profile, salinity, suspended matter content etc.|