The advanced Sharpshooter from Balluff Inc. (Florence, KY, U.S.; www.balluff.com) is a compact vision-based sensor designed for production error proofing. It takes advantage of a vision imaging system to provide both presence/absence and more complex inspection functions while using a simple software setup and sensor-like hardware platform. With the ability to store up to 20 jobs internally and switch swiftly between different projects —in less than 500 milliseconds, the Sharpshooter is especially suited for assembly lines that handle several product versions.

In a case where several different ovens or dishwashers are made from the same base model for different private labels, for example, “a Sharpshooter could be used to inspect the correct type of control panel and also verify the presence of the control knobs,” says Mark Sippel, product marketing manager—object identification, photoelectric sensors. In the case of refrigerator assembly, he adds, “a Sharpshooter could be used to locate and verify the correct type of water solenoid valves and hose connections for models requiring in-door water/ice dispenser and automatic ice makers.” In those situations, Sippel says, the Sharpshooter can prove more reliable than manual inspection and more cost-effective than multiple sensors.

“Sharpshooter combines several features not found on a simple sensor hardware platform and at this low cost,” according to Sippel. At 58 × 52 × 40 mm, the sensor features a standard vision resolution of 640 × 480 pixels and a combination of tools, including simple brightness and contrast detection, advanced edge detection methods, contour detection, optical character verification (OCV) tool, and 360° part rotation recognition.

The 360° pattern match tool uses an algorithm called geometric pattern matching (GPM). GPM works by locating intersections between edges in the model pattern, and builds a relationship map of those points to each other in memory. “When a live image is introduced, the algorithm tries to find the same mapped pattern in that image regardless of the rotation of the detected pattern in the image,” explains Sippel. “The user can set the minimum allowable percentage of points detected as an acceptable match, and set the allowable degrees of rotation if less than 360° is desired. If the pattern is detected, the rotation and X, Y coordinates of the detected pattern are used as a location reference for any other of the 24 tools that can be combined for inspection in the image to compensate their positions to follow the pattern or part.” Sippel says this allows the user to completely inspect a part, or a rotated feature on a part, and thus eliminate the need for fixturing or manual inspection. “This could also be used to error proof something not possible in the past with discrete sensors because of the rotation factor.”

The advanced Sharpshooter comes with added output logic functionality, which allows the user to use Boolean logic to determine how any of the three discrete pass/fail outputs behave. The output logic is configured using a simple graphic interface, through which the user can link any tool or combination of tools, such as brightness or patten match, to any output.

The new Sharpshooter uses an updated version of its free ConVis configuration software that supports all sensors in the product line. “Our interface is designed to be used by manufacturing engineers and maintenance personnel, not vision experts. So it addresses the Sharpshooter like a smart sensor interface, not a complex vision system,” Sippel tells APPLIANCE. “Many users are able to understand and start using the interface in just minutes after a short introduction.” The ConVis software also runs online and offline as an emulator. “Users can capture images from the Sharpshooter on the line through Ethernet at their desk and use the images offline to change or create projects with full sensor functionality and results simulation,” says Sippel.

Capable of an inspection cycle time as fast as 25 milliseconds per trigger, the Sharpshooter is available in three versions. The BVS-E type, designed to be used over an Ethernet connection and network, comes in two versions. The standard version has seven different error proofing tools, while the advanced version also includes 360° pattern matching, output logic, and higher processor speed. The BVS-C stand-alone version can operate without a PC. It has six tools from the standard version and an OCV tool.

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