Twenty-metre measurement with a 0.8 m near limit
The BBDM-25KR20M is an air-coupled ultrasonic distance transducer with a 25 kHz center frequency and a reference range of 0.8 to 20 m. It can be evaluated for large-tank level monitoring, industrial distance measurement, collision avoidance, area monitoring and long-range target detection.
The 0.8 m lower limit is important when the closest target or highest liquid level approaches the sensor. It should be included in the mechanical layout rather than treated as a distance that can be recovered through software alone.
Technical specifications
| Parameter | Specification |
|---|---|
| Model | BBDM-25KR20M |
| Center frequency | 25 kHz +/-5% |
| Recommended range | 0.8-20 m |
| Minimum impedance | 570 ohm +/-20% |
| Capacitance | 5,500 pF +/-20% at 1 kHz |
| Operating voltage | Peak voltage below 1,500 Vpp |
| Operating temperature | -40 to +80 degrees C |
| Pressure rating | Up to 3 kgf or 0.3 MPa |
| Beam characteristic | -3 dB half-power angle: 11 degrees +/-10% |
| Housing material | PTFE |
| Protection rating | IP68 |
| Weight | 1,285 g +/-5% |
Beam clearance over the measurement span
The 11-degree half-power angle provides a narrower main field than several lower-frequency long-range models. It still expands with distance; vessel walls, fill pipes, structural members or nearby machinery within the full 20 m path can therefore introduce unwanted echoes. Target tilt and surface texture affect the returned signal.
Electrical matching
The transmitter and receiver should be matched to the 570-ohm minimum impedance, 5,500 pF capacitance and stated peak-voltage limit.