SR50A-L Sonic Ranging Sensor
Robuster Ultraschall-Sensor
Typischer Einsatzbereich ist Schneehöhenmessung
wetter wasser energie gas flux and turbulence bauwerke boden

The next generation of the SR50A snow-depth sensor is now available.

Check out the SnowVUE™10.

Überblick

Akustischer Schneehöhensensor

Der SR50A ist ein robuster akustischer Sensor zur Messung der Distanz zu einem Ziel. Normalerweise wird er genutzt, um Schneehöhe zu messen, andere Anwendungen sind aber auch möglich. Er wurde von Campbell Scientific Canada entwickelt und enthält einen Algorithmus, der mehrfache Echos auswertet, um bessere Genauigkeit zu erhalten. Er ist mit fast allen Campbell Datenloggern kompatibel, da er ein SDI-12-Signal ausgibt.

Temperaturkompensation

Der SR50AT enthält einen externen Temperatursensor zur Kompensatione der Schwankungen der Schallgeschwindigkeit mit der Temperatur, es kann aber auch ein Temperatursensor an der Station mit dem SR50A verwendet werden.

Beheizte Variante

Der SR50A und der SR50AT sind mit eingebauter Heizung erhältlich, um Vereisung zu vermeiden. Man kann auch noch nachträglich eine Heizung anbauen.

Hinweis: Beim Einsatz in marinen Umgebungen kann es Probleme geben. Campbell Scientific empfiehlt dafür den SR50A-316SS-L .

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Funktionen und Vorteile

  • Wide operating temperature range
  • User-selectable options for output
  • Rugged enough for harsh environments
  • Uses a multiple echo processing algorithm to help ensure measurement reliability
  • Compatible with most Campbell Scientific data loggers

Bilder

Technische Beschreibung

The SR50A was designed to meet the stringent requirements of measuring snow depth, and it uses a multiple echo processing algorithm to help ensure measurement reliability.

SDI-12, RS-232, and RS-485 output options are available for measuring the SR50A. Campbell Scientific’s MD485 interface can be used to connect one or more SR50A sensors in RS-485 mode to an RS-232 device. This can be useful for sensors that require lead lengths that exceed the limits of either RS-232 or SDI-12 communications.

The SR50A replaced the SR50 in March 2007. The newer SR50A is smaller and has different output options than its predecessor. The SR50AH is available with a heater option for locations where rime ice is a problem.

Spezifikationen

Measurement Description Snow depth
Measurement Time < 1.0 s
Measurement Range 0.5 to 10 m (1.6 to 32.8 ft)
Output Options SDI-12 version 1.3, RS-232, RS-485 (output options selected by configuring internal jumpers)
Baud Rates 1200 to 38400 bps (RS-232, RS-485 modes)
Power Requirements 9 to 18 Vdc (typically powered by data logger’s 12 Vdc power supply)
Beam Acceptance ~30°
Resolution 0.25 mm (0.01 in.)
Accuracy ±1 cm (0.4 in.) or 0.4% of distance to target (whichever is greatest). Requires external temperature compensation.
Operating Temperature Range -45° to +50°C
Temperature Accuracy
  • ±0.2° (at 0° to 50°C)
  • ±0.75° (at -45° to 0°C)
Compliance CE Compliant
Length 10.1 cm (4.0 in.)
Diameter 7.5 cm (3 in.)
Cable Weight 250 g (8.2 oz) for a 4.57-m (15-ft) cable
Weight
  • 375 g (13.2 oz) without cable
  • 1.0 kg (2.2 lb)

Maximum Cable Length
-NOTE- Cable lengths greater than 60 m require a heavier gage wire if the power supply drops below 11 Vdc.
SDI-12 60 m (200 ft)
RS-232 60 m (200 ft)
Baud rates ≤ 9600 bps
RS-485 300 m (984 ft)

Power Consumption
Active 250 mA (typical)
Quiescent SDI-12 Mode < 1.0 mA
Quiescent RS-232/RS-485 Modes
  • < 1.25 mA (≤ 9600 bps)
  • < 2.0 mA (> 9600 bps)

Kompatibel mit

Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.

Datenlogger

Product Compatible Note
CR1000 (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR1000X SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR300 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR3000 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR310 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR350 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR6 SDI-12, RS-232, and RS-485
CR800 (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR850 (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.

Miscellaneous

Product Compatible Note
GRANITE 6 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.

Dokumente

Downloads

SR50A/AT OS v.1.3 (52 KB) 22-08-2007

Current SR50A / AT firmware.
Liste der Änderungen

SR50A example programs v.1 (11 kB) 22-01-2020

CR6 and CR1000X programs that directly read each type of SR50A output (SDI-12, RS-232, RS-485), and a CR1000 program that reads the RS-485 output using an MD485 Multidrop interface. A 107 sensor provides the temperature measurement needed for temperature compensation. The programs use the data filtering method described in the manual.

FAQs für

Number of FAQs related to SR50A-L: 15

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  1. To replace the transducer heads on an SR50A-L, is there a torque specification for the screws?

    No.

  2. Can the range operation of the SR50A-L be increased?

    No.

  3. Does the SR50A-L need a temperature probe?

    Because the speed of sound changes with temperature, Campbell Scientific recommends using the SR50A-L in tandem with a temperature sensor for the most accurate measurements.

  4. How can snow depth less than 0.5 m be measured using an SR50A-L?

    Position the sensor at a height that is between 0.5 m and 10 m above the target.

  5. Can the SR50A-L handle a coastal environment with humidity and salt spray?

    This sensor requires regular maintenance in a marine environment. The SR50A-L functions properly if care is taken to keep the vent free of salt accumulation and the interior free of moisture by replacing the desiccant as needed. It may also be necessary to carefully clean the face of the sensor to remove salt deposits.

  6. What is the potential error over a range of cold and warm temperatures with the SR50A-L if no temperature compensation calculation is applied to the measurement?

    The potential error is roughly ±0.4% of distance for a ±25° Celsius variation away from 0° Celsius.

  7. Can the SR50A-L be used in small-diameter wells?

    No. This causes echoes and reflections that confuse the sensor.

  8. Can an SR50A-L be hardwired to a data logger that is 2,000 ft away with no direct line of sight?

    No. The maximum cable length is approximately 800 ft.

  9. What is the maximum cable length available for the SR50A-L?

    Approximately 800 feet. This is a function of the limitations of the SDI-12 signal.

  10. Can the SR50A-L be recalibrated?

    The sensitivity can be adjusted slightly at the factory, but it cannot be recalibrated. Typically, the transducing diaphragm needs to be replaced periodically to maintain calibration. This can be done by the user or at the factory.

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