Proximity ultrasonic transducer BBDM-21KR30M

measurementfor level measurementfor obstacle detection

Product overview
The BBDM-21KR30M is an air-coupled ultrasonic distance transducer with a 21 kHz center frequency and a reference range of 1.0 to 30 m. It is designed for large-tank level monitoring, industrial distance measurement, collision avoidance, area monitoring and long-range target detection. At extended ranges approaching 30 m, echo margin depends on target area and orientation, airborne attenuation, temperature gradients, mounting alignment and receiver design, which all affect whether the return signal can be separated from noise and unwanted reflections.

Technical specifications (table)
Parameter — Specification
Model — BBDM-21KR30M
Center frequency — 21 kHz ±5%
Recommended range — 1.0–30 m
Minimum impedance — 1,100 ohm ±20%
Capacitance — 11,000 pF ±20% at 1 kHz
Operating voltage — Peak voltage below 1,500 Vpp
Operating temperature — -40 to +80 °C
Pressure rating — Up to 3 kgf (0.3 MPa)
Beam characteristic — -3 dB half-power angle: 13° ±10%
Housing material — PTFE
Protection rating — IP68
Weight — 1,020 g ±5%

Echo margin and vessel layout
The 13° half-power beam must be kept clear of fill pipes, reinforcement, wall transitions and other structures that may create earlier returns. The 1.0 m lower end of the reference range defines the highest measurable level in confined vessels.

Electrical matching
The assembly mass is 1.02 kg. Drive and receive circuitry should be matched to the stated impedance, capacitance and peak-voltage limit to ensure correct performance.

Specifications / technical data

• Model: BBDM-21KR30M
• Center frequency: 21 kHz ±5%
• Recommended range: 1.0–30 m
• Minimum impedance: 1,100 ohm ±20%
• Capacitance: 11,000 pF ±20% at 1 kHz
• Operating voltage: Peak voltage below 1,500 Vpp
• Operating temperature: -40 to +80 °C
• Pressure rating: Up to 3 kgf (0.3 MPa)
• Beam characteristic: -3 dB half-power angle 13° ±10%
• Housing material: PTFE
• Protection rating: IP68
• Weight: 1,020 g ±5%