Sonic Distance Sensor
The SR50A is a rugged acoustic sensor for measuring the distance from the sensor to a target. This sensor is typically used for snow depth or water depth measurements, but it is well-suited for other uses.
Because the speed of sound in air varies with temperature, an independent temperature measurement is required to compensate the distance reading. A simple calculation is applied to initial readings for this purpose.
Note: Campbell Scientific recommends model SR50A-316SS-L for marine environments.
Benefits and Features
- Wide operating temperature range
- User-selectable options for output
- Compatible with most Campbell Scientific data loggers
The SR50A was designed to meet the stringent requirements of measuring snow depth and water 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.
|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)|
|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|
|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|
|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 (196.9 ft)|
|RS-232||30 m (98.4 ft)
Baud rates ≤ 9600 bps
|RS-485||300 m (984.3 ft)|