SR50A-L Sonic Distance Sensor
Rugged acoustic distance sensor
Typically used for snow depth measurements
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Visão Geral

The SR50A Sonic Distance Sensor provides a non-contact method for determining snow depth. It determines depth by emitting an ultrasonic pulse and then measuring the elapsed time between the emission and return of the pulse. An air temperature measurement is required to correct for variations of the speed of sound in air. 

Note: Campbell Scientific recommends model SR50A-EE-L for operation in extreme environmental conditions where corrosion is a concern (such as coastal regions).

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Benefícios e Características

  • 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

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Descrição Técnica

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.

Especificações

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)

Compatibilidade

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

Data Loggers

Product Compatible Note
21X (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR10 (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
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.
CR10X (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR200X (retired) SDI-12
CR206X (retired) SDI-12
CR211X (retired) SDI-12
CR216X (retired) SDI-12
CR23X (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR295X (retired) SDI-12
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.
CR500 (retired) SDI-12
CR5000 (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR510 (retired) 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 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR850 SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.
CR9000 (retired)
CR9000X (retired) SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface.

Distributed Data Acquisition

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.

Additional Compatibility Information

Data Logger Considerations

One single-ended channel per probe is required; an excitation channel can be shared by several probes.

Downloads

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

Current SR50A / AT firmware.
Visualize o Histórico de Revisões

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.

Perguntas Frequentes Relacionadas

Number of FAQs related to SR50A-L: 15

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

  2. 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.

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

  4. 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.

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

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