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The Roman Empire, which expanded throughout most of the Mediterranean and flourished for more than 500 years, developed what is probably the most effective method for assimilating new cultures. Every time the Romans would conquer a new city, they would not demand the citizens change their language, religion, or customs, but they would force the citizens to adopt the common Roman currency. The Romans understood that without a standard currency, the whole empire would not work as a single entity, but continue to function as fiefdoms.
The automated test industry is facing similar challenges due the wide variety of formats used to share information. For example, most test systems generate a test result report, yet it is difficult to find two companies, or even business groups, that generate or report the same information or use the same format. These differing reporting formats make it difficult for engineers to compare or share test results across groups. Test result reports are not the only type of information that test engineering groups could share. They also share information on the sequence of tests, units under test (UUTs), and test fixtures.
To solve the problem posed by the multiple formats for automated test information, the Naval Air Systems Command created a cross-functional group of test engineers, instrument vendors, and academics. The group developed the Automatic Test Markup Language (ATML), a set of IEEE standards that define the documentation and reporting of automatic test information.
The ATML Document Standards
The ATML standard consists of various XML documents that describe different components in a test system. Figure 1 illustrates the components in a test system that each ATML standard documents. Some ATML documents describe information related to test software. For example, an ATML TestDescription (TD) document describes the test conditions, limits, and execution flow of a test sequence. An ATML TestResults (TR) document includes information on the measurements and pass or fail values of each test, and other properties such as test operator name and station information.
Figure 1. ATML defines XML documents that describe different components in a test system.
Other standards describe the physical elements of a test system. ATML InstrumentDescription, ATML TestAdapter, and ATML UUT Description documents describe the measurement instrumentation, fixture, and UUT respectively. An ATML TestStation document describes the characteristics of the whole test station, such as connections between ports, uptime, and calibration dates. Finally, an overarching standard called ATML TestConfiguration uses the above standards to specify the necessary elements to run a UUT on a particular test system.
Implementing the ATML TestDescription Standard
ATML TD documents describe the types of measurements an automated test system must perform but not the way the test system must perform them. For example, an ATML TD document may include the following text to describe a measurement: With power off, measure resistance between V_CC and GND. With this text, a test engineer could implement test software to communicate with instrumentation, switch connections, and perform the measurement. Test engineers also use this information to understand the original goal of the measurement and maintain the test software more easily in the future. Finally, by standardizing on a common format for test description, engineers can more easily share information on their tests with other groups or organizations.
The biggest challenge of using ATML TD in the development process of a test system is translating the ATML TD document into a functioning test sequence. Manually translating an ATML TD document to a functioning test sequence requires significant time and effort. Understanding this challenge, National Instruments released the NI TestStand ATML Toolkit 1.0, which includes an ATML TD translator that converts an ATML TD document into an NI TestStand sequence and template code modules implemented as NI LabVIEW VIs and NI LabWindows™/CVI functions. The template code modules include the input and output parameters documented in an ATML TD document. Because the ATML TD document includes information on what must be tested but not how, the translator imports the requirements for each test into the template code modules as comments, but does not implement any functionality.
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Figure 2. The NI TestStand ATML Toolkit 1.0 can generate an NI TestStand sequence and template code modules implemented as LabVIEW VIs and LabWindows/CVI functions from an ATML TD document.
Implementing the ATML TestResults Standard
The most well-adopted ATML standard today is ATML TR. ATML TR documents store measured values, pass/fail results, and accompanying data (including test operator, station information, and environmental conditions). Companies have adopted ATML TR to help standardize test result reporting across the whole organization or as a first step in adopting ATML. Implementing the ATML TR standard is simple if you use NI TestStand as your test executive. NI TestStand has supported ATML as one of its standard report formats since 2004 and has continued to update the ATML TR generation functionality to reflect changes in the standard. With the new NI TestStand ATML Toolkit 1.0, developers can generate ATML TR reports that are compliant with the latest version of the standard and include more data elements than the default ATML TR generated by the latest version of NI TestStand.
ATML reports are generated behind the scenes by NI TestStand using a three-step process. The first step consists of the NI TestStand engine collecting results into the NI TestStand ResultList container. The system tracks and stores all test properties, characteristics, and values in the ResultList container. The second step generates a TestResults XML report using the data in the ResultList container. The third step is the application of an ATML-compliant TestResults stylesheet that formats and displays TestResults XML data in a user-friendly HTML format.
Is ATML Right for You?
Although ATML consists of multiple standards that document different aspects of a test system, adopting ATML in your organization does not require an all-or-nothing decision. Some companies may only experience challenges with sharing test result data across groups. Adopting ATML TR in these organizations can help standardize reporting and increase test result sharing and comparison. On the other hand, some companies may want to increase and standardize the documentation of all aspects of a test system to reduce development cost and improve long-term maintenance. For these companies, adopting most of the ATML standards can help increase test system documentation by defining which aspects of a test system must be documented and increase standardization through common document formats. Like the Romans, you must find the critical aspects of test system information that you must standardize in your organization. As much as you would like to standardize all aspects of the test system development process, defining your own company’s Roman currency will give you the most bang for your buck.
Learn more about how National Instruments supports ATML.
Santiago Delgado is the NI product manager for NI TestStand and NI Requirements Gateway. He started his career at NI in 2005 as a member of the Engineering Leadership Program where he worked in the applications engineering department and led efforts for the launch of LabVIEW 8 in Italy and Spain. He holds a bachelor of science in management information systems from the University of Nebraska – Lincoln.
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