One of our customers, located in Italy, uses our IRU-9429 ultrasonic sensor to monitor the amount of snow that has accumulated on a roof of an apartment building. This way the customer will know whether the roof is in jeopardy of structural failure without having to risk human safety by sending somebody up there to take a look.
Measuring snow levels bring a unique set of challenges. So here are four tips for doing it right:
For ultrasonic sensors, an ideal target is hard and smooth. Snow, on the other hand, is a soft target since it will not always accumulate in a way that will result in a flat surface. For this reason, our customer in Italy used an electrostatic sensor, the IRU-9429 which has high sensitivity.
Another technique when challenged by soft targets is to use a higher powered sensor. For example, if you have a sensing range of about 20–25 feet we recommend that you use a sensor with a 50 foot range. With that extra power, the sound wave is less likely to get “lost” in the target.
If ice forms on the face of the transducer, the sensor will be unable to provide accurate readings. Our customer in Italy overcame this by installing a cone around the housing of the sensor. The sensor was protected from debris and didn’t allow ice to form around the transducer but was open at the bottom allowing the sound waves to reach the target.
It’s important to understand beforehand that ultrasonic sensors will unlikely give dependable readings during a snowstorm. The sound waves will lock up on the precipitating snow. However, after the storm has died down and the field is clear between the sensor and the surface of the snow, accurate readings will return.
In many cases, it will be most convenient to set up remote monitoring via the Internet. Many applications may require remote sensing due to shear distance. However, even applications where the sensor is just outside, as with our Italian customer, the complexity of wiring to a local display is often not worth the effort. You should at least plan to investigate the pros and cons of remote sensing before you buy your sensor.
If you have experience with snow level measurement or if you would like to learn more, please contact us at sales@apgsensors.com.
