Improving Test System Scalability with Test Management Software

Your product is a success in the market and it poses a test engineering challenge: you must expand your test system to incorporate 10 times the number of units it was originally designed to test. Modular platforms such as PXI ease the pain of hardware expansion through reduced cost and footprint, but you still need software. With test management software such as NI TestStand and NI Switch Executive, you can efficiently scale and optimize your test system and achieve higher performance.

 Figure 1. Parallel test reduces test time without additional instrumentation by implementing a pipelining architecture.

 Figure 2. Autoscheduling can further reduce test time by reordering tests and increasing the use of existing instrumentation.

Implementing Parallel Process Models

NI TestStand facilitates meeting throughput goals with parallel test by implementing parallel process models. Parallel process models can build a pipeline architecture that shares instruments across multiple units by staggering the execution of each test sequence (see Figure 1). If you created a parallel test system from scratch, the burden of building a pipelined test architecture would fall on the software engineer. NI TestStand alleviates this issue by providing tools to implement and optimize parallel architectures, such as the new resource usage profiler, which generates a graphical representation of test system execution and instrument usage statistics. With parallel process models, you can scale your entire parallel test system to incorporate additional units under test (UUTs) by changing a single parameter.

Pipelining increases the throughput of test systems, but there is still an opportunity to further optimize instrument utilization. With the NI TestStand autoscheduling and resource profiling features, you can further increase throughput up to 65 percent by reordering tests to take advantage of the time when instruments are idle, as seen in Figure 2.

Incorporating Switch Management Software

NI TestStand also accelerates the process of scaling test systems through integration with NI Switch Executive intelligent switch management software. Switching is often used to incorporate additional test points in a test system, but scaling switch code can be challenging due to the sheer density of channels. NI Switch Executive facilitates the process of scaling test systems by simplifying switch code development through features such as graphical configuration and Microsoft Excel integration.

Using the graphical configuration utility in NI Switch Executive, you can configure your NI switch hardware by clicking on the illustrated representation of your switch hardware. You can then expand this framework to incorporate additional test points using the Excel integration feature. After transferring your configuration to Excel with the simple click of a button, you can employ powerful text editing features to easily scale your system from tens of channels to thousands of channels in minutes. The scaled switch configuration can be imported back into NI Switch Executive and deployed directly with NI TestStand.

With the reward of a product’s success comes the prodigious task of scaling your test systems. Although the “do-it-yourself” approach to software scaling appears cheaper initially, it can add significant development time and cost to your operations. The combination of software tools such as NI TestStand and NI Switch Executive simplify scaling your test system software and reduce your time to market. 

View a webcast on implementing and scaling a parallel test system.

This article first appeared in the Q3 2008 issue of Instrumentation Newsletter.

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