Ultrasonic Sensor's Strength & Sensitivity

balance is criticalA good sensor needs to have the power to get the job done, while being sensitive enough to pick up the finer details. To speak geek, it needs to be the right blend of He-Man and Professor X.

Some sensors come pre-configured to work optimally. Others are programmable in the field to accommodate a variety of nuances in an application.

Ultrasonic sensors, at least APG ultrasonics, are of the latter variety. While they don’t need to be configured in many circumstances, the settings are available in case you decide to take things into your own hands (you maverick, you).

Two of the most important settings you can manipulate are signal strength (power) and sensitivity. Let’s take a dive into each:

I Have The Power

The power setting, called pulses, on an APG ultrasonic sensor is critical. It controls how many pulses are in an individual ultrasonic burst. The more pulses in a burst, the more powerful the signal.

Increasing the signal strength is useful in a few scenarios. It helps the sensor detect far away objects or surfaces. It’s good for overcoming light dust or thin vapors. It enables the measurement of a lot of solids.

However, there is a dark side to increased power. More pulses mean a greater potential for detected echoes, even outside of the sensor’s beam path. You also run the risk of wearing out your ultrasonic transducer a bit faster because you’re working it harder.

The key is balance.

Your task is to find the setting where there is a strong enough signal to detect the primary target at all times, but that it remains tame enough that you don’t get false positive echoes.

To achieve this balance, you need sensitivity.

The Sensitive Side

Whereas the pulses setting increases the power of the signal, the sensitivity setting magnifies the signals being received. This is also known as gain.

Increasing the sensitivity of the sensor will magnify any echo – including the unwanted ones. This is an attempt to better detect a weak signal. It’s useful when you have environmental factors that weaken a signal, and you don’t have too many other objects in the sensor’s range.

The main role of sensitivity is to avoid the need to increase the signal strength too much. It serves to balance out the pulses so you can keep each setting reasonable.

If you set your sensitivity too high, you’ll start to get a noisy reading, and you open yourself up to false positives – particularly if the pulses setting is also high.

Both settings work together to provide the balance you’re after. The goal is to keep both of them as low as you can while still getting a strong signal. The environment in which your ultrasonic level sensor is installed will have a great effect on how you’ll program each setting.

Bigger Really Is Better

To keep both your power and sensitivity in check, make sure you have a big enough sensor – one with a sufficiently long range. Here, the size of the ultrasonic transducer is directly related to the frequency of the ultrasonic wave. As you may remember, low frequencies travel further and contain more energy than high frequencies.

So a 40-foot sensor would measure better at 25 feet than a 25-foot sensor would.

Why ramp up the pulses and sensitivity settings on a 25-foot ultrasonic just to make sure it’s adequately reading at its maximum range? It’s much better to keep those settings low and get a lower-frequency, longer-range sensor.

Let us help you achieve balance in your level measurement universe. Contact us to discuss your application and learn how you can measure up to your applications.

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top photo credit: Da Sal via flickr cc

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