SR50AH-L Heated Sonic Distance Sensor
Rugged, heated acoustic distance sensor
Prevents ice from coating the transducer
weather applications supported water applications supported energy applications supported gas flux and turbulence applications supported infrastructure applications supported soil applications supported

Overview

The SR50AH Heated Sonic Distance Sensor provides a non-contact method for determining snow or water 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. The SR50AH includes an integrated heater that prevents ice and rime from coating the transducer.

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Benefits and Features

  • Integrated temperature probe for providing temperature correction of measurements
  • Non-contact method for determining snow or water depth
  • Integrated transducer heater; rugged enough for rime and ice environments
  • Wide operating temperature range
  • User-selectable options for output
  • Uses a multiple echo processing algorithm to help ensure measurement reliability
  • Compatible with most Campbell Scientific data loggers

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Technical Description

The SR50AH was designed to meet the stringent requirements of measuring depths and uses a multiple echo processing algorithm to help ensure measurement reliability. The addition of a heating element around the transducer prevents ice and rime from coating the transducer with minimal power requirements.

SDI-12, RS-232, and RS-485 output options are available for measuring the SR50AH. Campbell Scientific’s MD485 interface can be used to connect one or more SR50AH 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.

Specifications

Measurement Time < 1.0 s
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)
Measurement Range 0.5 to 10 m (1.6 to 32.8 ft)
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
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

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)

Heater

Heater Resistance 75 ohm
Nominal Operating Voltage 12 V (ac or dc)
Use a properly conditioned low-noise power source. A noisy power source will affect operation of the sensor.
Maximum Rated Wattage 3 W
Maximum Rated Voltage 15 V (ac or dc)
Maximum Operating Temperature 25°C
Turn the heater power off at temperatures above 25°C. This prevents damage to the sensor and reduces power consumption.

Compatibility

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

Dataloggers

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.
CR200X (retired) SDI-12
CR216X (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.
CR5000 (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.
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
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

SR50AH heater control programs v.1 (4 kB) 22-01-2020

CR6 and CR1000X programs that read the SR50AH SDI-12 output and control the SR50AH heater. A 107 sensor provides the temperature measurement needed for temperature compensation. The programs use the data filtering method described in the manual.