Description
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
- Acoustic
- 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
Feature
- 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.
Spesification
| 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) |
| Electrical data | |
| Supply voltage | 12 … 16 V DC, typ. 12 V |
| Power consumption | 50 … 500 mW, depending on measurement cycle |
| Water level measurement | |
| (optional) | |
| Measuring range | 0.15 … 10 m |
| Accuracy | ±3 mm, depending on stratification |
| Pressure cell (optional) | |
| Measuring principle | Piezo-resistive |
| Measuring range | 0 … 10 m |
| Accuracy | ±0.25 % FS |
| Interfaces | RS-232, SDI-12 or SDI-12 via RS-485, Modbus (optional) |
| Environmental conditions | |
| Operating temperature | -5 … + 35 °C |
| Storage temperature | -20 … +70 °C |
| Length x Ø | 45 … 52.2 cm x 7.5 cm |
| Housing material | POM |
| Wall bracket (accessory) | |
| Components | Bracket, protective cover, and C rail mount |
| Material | Stainless steel |
| Details | On request |
| 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. |
