Automotive Sensor Testing Using a PXI-Based System

Author(s):
Bill Edwards - Aegis Solutions
Tim Fenwick - Aegis Solutions

Industry:
Automotive

Products:
PXI/CompactPCI, LabVIEW

The Challenge:
Developing an automated system for rapidly testing automotive engine sensors that provides highly accurate, repeatable, and reproducible measurements.

The Solution:
Designing and deploying an electro-mechanical system using National Instruments PXI hardware and LabVIEW software platforms to meet or exceed the customer’s requirements.

Testing Multiple Engine Sensors
Standard Motor Products, a manufacturer of various automotive sensors and components, contracted Aegis Solutions to develop an end-of-line test system for a new product line that tests two different types of engine sensors. The customer required that the system be automated, accurate, reliable, and capable of testing more than 2,000 parts in a single shift. In addition, repeatability and reproducibility requirements had to be satisfied and the user interface had to be configurable between English and Spanish.

Precise Control
The customer’s engine sensor is a Hall Effect type sensor. A rotating vane has teeth that break the sensor’s magnetic field and produce a repetitive timing signal when the engine runs. This timing signal serves as the backbone for all synchronized engine functions such as spark plug firing, valve control, and engine control module operations. Because the test system required precise control of its servo motor, used to turn the vane, and synchronization of the acquired data with the motor movement, Aegis decided to take advantage of the tight integration between LabVIEW and the PXI data acquisition platform.

The system needed to test two types of sensors, so we designed multiple nests to hold and secure a part during testing. Adequately securing the part was crucial to delivering reproducible measurements. The nests are mounted on a platform lifted into position to allow the vane teeth to pass through the sensor’s magnetic field when the vane is turning. All of the proximity sensors, for determining if the part is in place, clamping solenoids, and pneumatic lift solenoids are read and controlled by a PXI-6527 digital input/output module.

Once the part under test is placed in position, the LabVIEW software commands the servo motor to start turning and once it has reached its target speed, the sensor’s output signal is captured as a waveform through a PXI-6052E data acquisition module and stored to disk. The system analyzes the waveform to determine the angular position of the edge of each tooth with respect to a reference point on the vane. These angles are compared against pass/fail limits to determine if the part is good or bad.

The signal’s amplitude value and angular position data are stored to a Microsoft Excel compatible file for each part tested. In the future, Standard Motor Products can use this data for statistical process control and can create comprehensive reports for their customers.

A Cost-Effective Solution that Exceeds Goals
National Instruments LabVIEW and PXI platforms allowed Aegis Solutions to develop a cost effective test system to meet or exceed all of the customer’s requirements. With this system, Standard Motor Products can exceed its testing throughput needs and ensure the functionality and quality of every part shipped to its customers.

For more information, contact
Aegis Solutions, Inc.
Tel: (800) 808-4675
www.aegis-solutions.com

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