Thursday, March 3, 2011

Vision and Measurements in PACs

National Instruments is extending PAC by incorporating machine vision capabilities and higher speed measurements with a background in measurements. Many industrial applications collect high speed measurements for power quality or vibration applications. The collected data is used to monitor the rotating machinery condition, identify motor wear, determine maintenance schedules, and adjust control algorithms. The data is normally collected using stands alone instrumentation or specialized data acquisition systems and is incorporated into a control system using a communication bus. National Instruments PACs can take high accuracy measurements directly at millions of samples per second, which are then passed directly into their control systems for immediate processing.

Engineers can incorporate vision into their control systems. Vision is an automation area that has gained a lot of momentum in the last decade. There are many flaws or mistakes that can be identified through visual inspection that are difficult to detect using traditional measurement techniques in a manufacturing environment. Common applications include part inspection for assembly verification or manufacturing, such as optical character recognition (OCR) to examine date codes or checking for correct component placement on a circuit board, to sort products, and optical measurements to find flaws in products or for sorting based on quality criteria. Many plants today use stand-alone smart cameras that need to communicate to the manufacturing process controller. The PACs of National Instruments incorporate vision or high speed measurements with motion and logic control eliminate the need for engineers to integrate dissimilar software and hardware platforms.

Although PACs show the latest in Programmable Controllers, the future for PACs hinges on the embedded technology incorporation. FPGAs (Field Programmable Gate Arrays) are electronic components commonly used by electronics manufacturers to create custom chips, allowing intelligence to be placed in new devices. These devices contain of configurable logic blocks that can perform a variety of functions, I/O blocks that pass data in and out of the chip, and programmable interconnects that act as switches to connect the function blocks together.

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