Detecting Pallets with Irregular Loads
Challenge
In packaging applications, it’s common for pallets to be loaded with boxes of differing shapes and colors. This can present a sensing challenge for traditional photoelectrics, which can be fooled by color, reflectivity, and inconsistent surfaces. A solution is needed that will reliably detect the pallet, regardless of box shape or color, as it passes on the conveyor.
Solution
An ultrasonic sensor will provide reliable pallet detection. Ultrasonic sensors emit sound waves and “listen” for the return echo of the sound wave bouncing off the target. The sensor can be taught a reliable background, in this case the conveyor, and will listen for sound waves returning from the conveyor. Any object getting between the sensor and the conveyor will be detected, causing the output to switch.
In this application, a U-GAGE QT50U Ultrasonic Sensor is being used. The QT50U provides extended range of up to 8 m, an ultrasonic dead zone of only 2.5% of the total sensing range, and simplified setup using push-button or remote TEACH-mode programming.