Designing an Automated RF Test System for Flexible Data Mining and Reporting with NI LabVIEW and DIAdem

Author(s):
James West - Summitek Instruments

Industry:
Aerospace/Avionics, Telecommunications, Government/Defense

Products:
LabVIEW, DIAdem

The Challenge:
Creating an automated RF test solution for improved analysis and reporting of historical test data.

The Solution:
Automating S-parameter measurement and developing a Web interface for comprehensive testing and report generation using National Instruments LabVIEW and DIAdem.

S-parameters, which help characterize the performance of passive and active devices, can be viewed in a variety of formats to provide unique insight into the characteristics of a device under test.

Two different customers challenged Summitek Instruments to create an Automated RF test system that automates S-parameter testing and improves their ability to analyze and retrieve data. One customer needed a better way to find historical test data and reproduce results, while the other wanted a more effective method for finding and analyzing test data for statistical process control (SPC).

Searching for a Better Method of Analyzing and Retrieving Test Data

Each customer already had a process for performing S-parameter measurements but no way to effectively access the data. We knew developing a proficient system would encompass:

• Identifying a test data storage method that does not require a customized file format for each customer
• Designing a test system that customers can adapt to fit their test processes
• Providing tools to easily mine and analyze test data
• Producing high-quality reports that customers can distribute as data sheets
• Making the test system accessible to basic and advanced users

The first problem we solved was finding a generic test data storage methodology. We needed a solution that could store S-parameter test data and custom user fields, as well as offer the tools necessary to access the test data. For this, we used the data storage VIs in LabVIEW. The data storage VIs provided a way to store S-parameter test data as well as custom information related to each test and product.

The data storage VIs use XML-based technology to build an information hierarchy, which stores file, group, and channel information in .TDM files. We mapped the hierarchy so that files correspond to the products under test, groups correspond to each test run of a product, and channels correspond to each measurement.

We asked the customer to customize fields to associate with each test run (group). These customized fields are stored as properties of the test run. With the data storage VIs, we could store different data for each test run and each product tested. We also could store custom fields with the test data without a custom test data file format.

In addition, we wanted to provide a user interface that would be familiar to customers and give them the ability to release ongoing improvements to the product. We chose to use a server-based product strategy, which presented some not-so-obvious advantages such as the ability for customers to install their products on one computer and obtain access from multiple client locations. For example, test engineers in the United States can configure test sequences and access test data from a server in China. Another benefit to this approach is that customers can install improvements to the software on the server and make them immediately available to multiple test stations.

Our Spartan product uses an NI LabVIEW remote panel-based solution, and the Web interface we developed helps our customers configure and run tests as well as generate reports from a Web browser. Customers define which custom fields to use along with the S-parameter test sequences for each test run. Additionally, the Spartan collects the custom fields from the production technician and stores them and the test data on the Spartan server in .TDM data files. Company employees are able to generate test reports from any location with access to the Spartan server.

A database on the server combined with the .TDM data files provides an integrated solution that fulfills all of our requirements. Customers can store test parameters and the test data index in the Spartan database and the test data in the .TDM data files. Customers are able to search for data using standard fields such as product model number, serial number, or production technician name, and can data mine custom fields such as customer purchase order number or work orders. We created a simple query tool that constructs an SQL query for the test data index. The query results in a list of test data files that fit the criteria. As a result, customers are able to retrieve lists of products grouped by test station and perform SPC more efficiently.

We used NI DIAdem to load .TDM test data and report templates. Because DIAdem naturally incorporates the ability to access .TDM data files, it facilitates quick development of report-generation capabilities. With the rich features of DIAdem, customers can produce professional reports, including PDF reports, without extensive custom software.

A solution based on DIAdem offers other benefits. Advanced users can access the .TDM data files and create custom reports and custom analysis to fit their special needs. A complex data-mining tool in DIAdem offers additional capabilities beyond the scope of our test system. And, by using DIAdem in the Spartan product, we can accommodate basic and advanced users.

Savings Achieved with Spartan

Using data mining within Spartan, one customer was able to find and reproduce test data reports immediately, whereas the customer previously spent hours searching through boxes looking for printed test results. The customer was able to save on labor costs and shift the technicians to production.

We cut development time for our report-generation capability significantly and realized a dramatic savings from concept to report as compared to prior projects with report-generation capability. Elimination of custom file format definitions for each customer saves development time, so we can concentrate on adding features to the product.

For more information, contact:

James West
Senior Software Engineer, Summitek Instruments

12503 E. Euclid Driver #10

Englewood, CO 80111

Tel: (303) 768-8080

E-mail: jwest@Summitekinstruments.com

 

 

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