An automotive sensor manufacturer committed to a no-defects standard needed to test each product throughout the assembly process. The company also wanted to increase product throughput to one part every 6 s, and the test equipment had to be interoperable with existing PLC-based systems from Allen Bradley (www.ab.com) and power supplies from other vendors. ABCO Automation, Inc., landed the job of developing a full-line conveyor assembly and test machine.
The plant components to be upgraded consisted of two large, designated machine sections with precision link indexing conveyors: a 14-station assembly and verification line, and a 10-station final test line. In the first line, the parts are overmolded and loaded onto the conveyor for complete assembly, verification, visual inspection, and welding. Multiple DENSO robots (www.denso.co.jp/en) load and unload the sensor assemblies into the second line for final testing.
For the testing phase, ABCO selected National Instruments' (www.ni.com) PAC platform because of its speed, accuracy, and interoperability with other control systems. Using NI's PXI-1042 chassis and PXI-8186 controller along with several PXI-6070E data acquisition modules, ABCO's system acquires waveforms from an encoder connected to a tonewheel operating at a specified rpm count. The system analyzes the waveform data for duty cycle, high and low values, and other parameters that determine PASS/FAIL. Acceptable parts go to packaging, and parts that fail are isolated, marked, and put into a reject pile.
A key factor in the project's success was the LabVIEW OPC's capabilities and interoperability with PLCs. Using NI's LabVIEW DataSocket technology and an RSLinx OPC server from Allen Bradley, ABCO integrated NI hardware with conventional PLCs for seamless control and monitoring of all data. Good communication between NI equipment and Allen Bradley hardware minimized programming and integration time. And the sensor manufacturer is enjoying better performance and cost savings as well.