The RW04 is a non-contact radar level sensor for sea water, supplied inside a custom protective enclosure made by SpaceEcho. It sends radar waves down a sounding tube. The waves reflect off the water surface and return to the sensor, which calculates the distance. Because nothing touches the water, marine growth and changing environmental conditions do not affect the reading. It is one of the three level sensors used with the Tide Gauge Station, alongside the Acoustic Level Sensor and the Piezometric Level Sensor.
RW04 radar level sensor mounted on a pier above the sea (illustration).
Features
Non-contact
The sensor stays dry above the water.
1 mm resolution, ±2 mm accuracy
For tide and sea-level records.
Fast response
100 ms.
Custom protective enclosure
Designed and made by SpaceEcho around the radar sensor.
IP68
Sealed against dust and immersion.
Specifications
Measuring range
0.1–40 m
Accuracy
±2 mm
Resolution
1 mm
Frequency
76–81 GHz
Response time
100 ms
Medium temperature
−40–85 °C
Protection
IP68
Output interface
Analog; digital Modbus RS-485
Supply voltage
12–36 V DC
Choosing a level sensor
A SpaceEcho station can measure water level with three sensor types. The right one depends on the site, the range and the accuracy needed.
Piezometric — PSL03
Submerged. Works where nothing can be mounted over the water, and is not affected by air temperature, fog, spray or foam on the surface. Limits: range of 5 m, accuracy of ±0.5 % F.S., and the probe is in contact with the water, so it needs cleaning and checks against a reference level. See the Piezometric Level Sensor.
Radar — RW04
Non-contact, from above. Range 0.1–40 m, accuracy ±2 mm, IP68. The measurement does not depend on air temperature or humidity. Limits: it needs a mount over the water with a clear view of the surface.
Ultrasonic — USW02
Non-contact, from above. Range 28–700 cm, accuracy ±1 cm, with built-in temperature and humidity correction. A lower-cost option for level and wave monitoring. Limits: shorter range and a wider error than radar, and the beam (11°) needs a clear path to the water. See the Acoustic Level Sensor.
