Starflow QSD SDI-12 Instrument

6527A Starflow QSD

  • Overview

    The Unidata Starflow QSD SDI-12 Instrument is used to measure water velocity, depth and temperature of water flowing in rivers, streams, open channels and large pipes.
    When used with a companion Unidata IP data logger total flow can also be calculated.

    Starflow QSD SDI-12 Instrument is
    • Easy to use
    • Robust, reliable – completely sealed against water ingress
    • Inexpensive – to buy, install and operate, excellent ROI
    • Easy to web-enable – view data on-line with Neon
    • Easy to install – compact, will easily fit most structures
    • Low maintenance – no battery changes or calibration
    • Miserly on power – no fussy power arrangement needed

    Starflow QSD SDI-12 Instrument Applications
    • Measure total discharge from defined pipes and culverts
    • Indicate a need for hydrometric station rating changes
    • Monitor urban flooding prone to backwater effects
    • Monitor low-fall, flat land downstream confluences
    • Monitor water flow as a vector of contaminated runoff
    • Trigger storm-water sampling

    Starflow QSD SDI-12 Instrument uses up-to-date technology to overcome limitations sometimes experienced with earlier instruments.
    Starflow QSD SDI-12 Instrument uses the Ultrasonic Doppler Principle in Quadrature Sampling Mode to measure water velocity. It transmits ultrasonic energy through its epoxy casing into the water. Suspended sediment particles, or small gas bubbles in the water reflect some of the transmitted ultrasonic energy back to Starflow QSD SDI 12 Instrument’s ultrasonic receiver. Instrument then processes this received signal and calculates the water velocity.

    Water depth is also measured with an ultrasonic depth sensor. This technology enables the Starflow QSD SDI-12 Instrument to be completely sealed; potted in a solid block of ‘ultrasonic-transparent’ epoxy and free from any potential leaks that might otherwise occur.

    Ultrasonic depth sensor integration overcomes conventional pressure sensors susceptibility to damage from water-borne debris, and eliminates the need for frequent recalibration to maintain accuracy. On top of that, Starflow QSD SDI 12 Instrument’s low-profile form-factor minimises disturbance to the flow it is measuring. Starflow QSD SDI-12 Instrument is suitable for use in a wide range of water qualities, from sewage to potable water and everything in between, including sea water. However, it may not be as effective in clean, gas-free water.

    Starflow QSD SDI-12 Instrument measures velocity in both directions and with a companion Unidata IP data logger may be programmed to compute flow rate and total flow in pipes and open channels of known dimensions.

    Simply mount it on, or near the bottom of the water channel.

  • Specifications

    20mm/s to 1600mm/s in one direction (default)
    20mm/s to 3200mm/s in one direction (parameter setting)
    Bidirectional flow capability (parameter setting)

    Accuracy: 2% of measured velocity
    Resolution: 1mm/s

    Range: 20mm to 2000mm – above sensor in water with heavy sediment
    Range: 20mm to 5000mm – above sensor in water with medium sediment
    Accuracy: Typical ±1%

    Range: 0°C to 60°C
    Resolution: 0.1°C

    Voltage Range: 10 to 24V DC
    Supply Current: 50uA standby, 100mA active for 1s
    Power Source (typical): External battery 12V DC

    SDI-12: Velocity, depth, temperature and diagnostic features
    Connection: Single three-wire cable up to 50m long
    Software: Compatible with Starlog V4

    Operating Temp: 0°C to 60°C water temperature
    Storage Temp: -20°C to 85°C
    Humidity: 100%

    Dimensions: L 135mm x W 50mm x H 20mm
    Material: Epoxy-sealed body, stainless steel mounting plate
    Weight: 200g
    Cable: 15m, three wire
    Cable Options: User specified length up to 50m

  • Ordering Information

    Full product consists includes mounting bracket

    6527AStarflow QSD SDI-12 Instrument
    6527A-SSpecial cable length (up to 50m) Starflow QSD SDI-12 Instrument

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  • Documents

    Brochure – 6527A Starflow QSD

    Manual – 6527A Starflow QSD

    Application Notes
    CSIRO Remote Automated Water Quality Stream Gauging System Design
    Irrigation Channel Measurement and Control
    Flood Monitoring / Flood Alerts
    Rivers and Streams Monitoring
    Surface Water Monitoring
    Industrial Outflow Monitoring

  • Q: Does the velocity measurement has a ‘dead band’ close to the ultrasonic eyes and if so, what is the dead band distance?

    A: The QSD has a half power beam width of 2.8 deg which means the transmitter & receiver beams begin to intersect about 100mm from the face of the instrument. However this is the half power width; lower power intersection occurs closer than 100mm and given the receiver sensitivity will contribute to the velocity detection. Suspended particles reflect the signal at many angles, so even before the beams intersect there will be high angle Doppler reflections that are received.
    Also, the beams will be internally reflected off a shallow water surface and mix further “upstream” so it is difficult to determine where the maximum signal is coming from and even more difficult to say if there is a dead band and how large it is.

    Hence, the zone of maximum sensitivity lies from 100mm to 300mm from the instrument but it depends on water level (reflection) and quality (number of reflectors).

    Instrument will detect velocities from 25mm onwards.

    Q: Can the Starflow QSD be used in small pipes

    A: We have been testing the operation of QSD’s in a 150mm pipe for some months now.
    The performance of QSD’s in this arrangement is good. Just watch for turbulence and if you plan to use a dam, watch for standing waves.
    We have a small pipes test tank here at Unidata. It consists of a 150mm PVC pipe and submersible pump etc.
    We have been running these QSD’s down to a depth of about 60mm in this arrangement with no real problem.

Starflow QSD SDI-12 Instrument