This product is no longer available and has been replaced by: SNOWVUE10. Some accessories, replacement parts, or services may still be available.
| Services Available | |
|---|---|
| Repair | Yes |
| Free Support | Yes |
Overview
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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Benefits and Features
- 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
The "-L" on a product model indicates that the cable length is specified at the time of order.
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Detailed Description
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.
Specifications
| 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 |
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| 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 |
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Maximum Cable Length |
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| -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 |
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| Active | 250 mA (typical) |
| Quiescent SDI-12 Mode | < 1.0 mA |
| Quiescent RS-232/RS-485 Modes |
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Compatibility
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
Dataloggers
| 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 | |
| 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. | |
| CR300 | SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface. | |
| CR3000 (retired) | 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. | |
| 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 (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. | |
| CR9000 (retired) | ||
| CR9000X (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 |
|---|---|---|
| GRANITE6 | SDI-12 and RS-232. For RS-485, requires an MD485 interface or similar RS-485 to RS-232 interface. |
Documents
Downloads
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.
Frequently Asked Questions
Number of FAQs related to SR50A-L: 15
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The SR50A-L must be vented to the atmosphere to operate correctly. This is normally not a problem in alpine conditions, but in temperate, damp climates, the vent may introduce condensation that will ultimately disable the sensor. To combat this, a small package of desiccant is placed inside the sensor head, which will keep the interior dry under most conditions. If especially wet or condensing conditions are expected, the desiccant should be changed frequently to prevent moisture accumulation. Campbell Scientific offers a desiccant ½ unit bag (pn 905) and a 0.75 g desiccant bag (pn 4091).
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No. This causes echoes and reflections that confuse the sensor.
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Approximately 800 feet. This is a function of the limitations of the SDI-12 signal.
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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.
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No. The maximum cable length is approximately 800 ft.
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The potential error is roughly ±0.4% of distance for a ±25° Celsius variation away from 0° Celsius.
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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.
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Yes. This sensor has an SDI-12 output.
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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.
Case Studies
Currently, the Andean tropical glaciers are in an accelerated process of retreat. These glaciers are......read more
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