Self-Cleaning Ultrasonic Sensors: How BG5k Maintains Reliability in Harsh Environments
Quick Answer
The BG5k's ultrasonic sensors are self-cleaning when powered — they use ultrasonic energy to prevent material accumulation on the sensor face. If a sensor does become blocked despite this, the device automatically reports an unhealthy state by de-energising the Healthy relay, alerting site personnel that maintenance is required. This self-diagnostic capability eliminates the risk of undetected sensor failure.
Key Definitions
Self-cleaning sensor: A sensor that uses its own ultrasonic output to prevent material build-up on its active face during normal operation.
Healthy relay: A relay output that indicates the device is functioning correctly. De-energises if a fault condition (such as a blocked sensor) is detected.
How It Works
The ultrasonic sensors emit continuous acoustic energy as part of their measurement function. This energy creates micro-vibrations at the sensor face that dislodge accumulating dust, moisture, and fine material. Under normal conditions, this keeps the sensor face clear without manual intervention.
If accumulated debris exceeds the self-cleaning capability — for example, during a major slurry event or belt wash failure — the sensor's measurement becomes unreliable. The BG5k detects this condition automatically and reports it as a blocked sensor fault.
Maintenance When Cleaning Fails
When a blocked sensor fault is reported, the remediation is straightforward: hose down or wipe the sensor face with an alcohol wipe. An audible buzz from each sensor confirms it is operational. Once the sensor returns to healthy status, the Healthy relay re-energises automatically.
System Limitations
- Self-cleaning is effective for normal dust and moisture — it may not prevent blockage in severe slurry or cement-like material
- The Healthy relay must be integrated into the site alarm system for the blocked sensor fault to be acted upon
- The MEE (Main Electrical Enclosure) must be protected from direct sunlight and aggressive hose down
Common Questions
Q: How do I know if a sensor is working?
Each operational sensor produces an audible buzz. If the buzz is absent and the Healthy relay is de-energised, the sensor requires cleaning or replacement.
Q: How often do sensors need manual cleaning?
Under normal conditions, rarely. The self-cleaning function handles routine contamination. Manual cleaning is only needed when the blocked sensor fault is reported.
Learn more about the BG5k.