Distance measurement technology selection is the first decision: laser for precise and long-range non-contact, ultrasonic for any target including liquids and bulk solids, radar for harsh environments and tank level, capacitive for in-tank or through-wall level. Pick the wrong technology and accuracy targets become unreachable regardless of sensor quality.
Specs to confirm before ordering:
- Technology: laser time-of-flight (long range, weather-tolerant), laser triangulation (sub-mm short range), ultrasonic (universal target type, affected by air currents and foam), 80 GHz radar (long range, immune to dust/steam, expensive), capacitive (in-tank level, conductive or non-conductive media)
- Operating range and required accuracy
- Target material — laser needs reflective surface, ultrasonic struggles with foam and soft surfaces, radar needs a target large enough relative to its beam, capacitive needs media with adequate dielectric constant difference
- Environmental conditions: dust, steam, temperature swings, vibration, washdown
- Output: analog 4–20 mA, switch, IO-Link, fieldbus
- Mounting and installation constraints — straight-line of sight for non-contact, vessel access for contact-style
- Eye-safety classification for laser models
Common gotchas: ultrasonic sensors fail on foam, fabric, and soft insulation — these absorb the acoustic pulse. Laser sensors are affected by direct sunlight on bright reflective targets (over-range error) and by smoke or dust in the air path. Radar sensors need a target large enough to fill the radar beam at the target distance — small narrow targets at long range may not return enough signal. Capacitive level sensors require careful setup of the empty/full reference points; an installed unit reads wrong until calibrated to the specific tank and media.
Typical applications: AGV positioning and obstacle detection (laser time-of-flight), tank level on liquids (ultrasonic, radar, capacitive), web loop control (laser triangulation), bulk-solid level in silos (radar, capacitive), and overhead crane height position (laser time-of-flight). For legacy installations, in-kind replacement preserves the analog scaling, the mounting geometry, and the controller's expected behavior at out-of-range conditions.
For obsolete distance measuring sensors, send the OEM part number for a sourcing quote.
