Package Measurement in a Second—Ultrasonic Sensors Detect Any Surface

For the Italian transport and logistics company Villa & Riva, it is important to know the exact size and weight of their shipments. This is the only way to ensure that their storage capacity is used optimally and that trucks are not overloaded. To record the volume and weight of their shipments automatically, the company uses the Parcelscan mobile measuring table from SIPI. Ultrasonic sensors from Pepperl+Fuchs take rapid and accurate measurements of the outer edges.

SIPI Parcelscan features integrated scales to calculate the weight of the goods, while the length of the outer edges is detected by ultrasonic sensors. In this process, the packages are positioned on the table in a corner that is bordered by end strips on two sides. There is an ultrasonic sensor at the free ends of the two strips. The sound beams of these sensors are aligned toward the package along the relevant edge and register its length and width. The height is detected by an additional sensor that is positioned over the table and records the package from above. 

Ultrasonic sensors are particularly well suited to measuring the outer edges of the packages. They detect objects regardless of their optical properties. The measurement is not affected by the color of an object or by reflective surfaces as they do not impact the propagation and reflection of the sound waves. This means, for example, that packages can be reliably detected even if they are wrapped in glossy film or cellophane.

The SIPI Parcelscan is equipped with three ultrasonic sensors from the Pepperl+Fuchs UC2000-L2 series. The sensors have a range of two meters and detect the outer dimensions of the boxes with millimeter precision. As the lateral expansion of the sound beam can be limited without sacrificing the detection range, the devices can be positioned very close to the end strips of the table. That means small packages with an edge length of just a few centimeters can be measured. Positioning the sensors close to the outer edges ensures that the table can be easily loaded and unloaded. This is aided by the compact design of the cubic ultrasonic devices: "At an edge length of just 40 millimeters and a dead band of 60 millimeters, the sensors can be mounted at the end strips in a way that saves a lot of space. That means access to the measuring table is practically unobstructed," says Carlo Clerici from SIPI.

Since three sensors are required to measure the boxes, it was important to the developers at SIPI to ensure easy synchronization of the devices. To prevent any cross-talk between the signals of the individual sensors, the UC2000-L2 devices operate in automatic multiplex mode. They simply need to be connected via their standard synchronization inputs.

The SIPI Parcelscan measures a package in just one second. The data is displayed on a screen mounted on the measuring table. At transport company Villa & Riva, the data is assigned to the relevant freight by scanning the barcode and is then transferred to a computer via Wi-Fi or Ethernet. This ensures that the labels required for transport are printed immediately and the collected data is transmitted to the ERP system.

The freight handled by Villa & Riva consists mainly of boxes and cartons with even outer edges. However, SIPI Parcelscan also allows irregularly shaped objects to be measured. This is done by placing metal brackets in the measuring range of the sensors at the level of the component that is protruding the furthest. Instead of the actual freight, the sound beams detect the metal brackets, which indicate the size of the freight.