Double Ten Technology about standard automated test system architecture
Building a software-centric ecosystem must be achieved through a standardized architecture. People expect automatic
The performance of the test system is more and more powerful, and the function is more and more perfect, which means the complexity of the system increases.
Potential risks of increased complexity include reduced system stability, prolonged development cycle, and increased maintenance and upgrade difficulties
The decrease of system reuse rate leads to the decrease of return on investment, so the standard automated test system reference architecture
Very important. In the test and measurement industry, the most common automated test system architecture is the five-tier architecture model,
The model is divided into instrument, test station, instrument driver, application development environment and test
Management software, as shown in Figure 1-8.
The automatic test system includes test station, instrument and test software. Five-story structure model
The first and second layers are the hardware components of the automated test system. The instruments and equipment can be PXI module and VXI mode
Block, traditional GPIB bus interface instrument; The test station can be a desktop PC, industrial computer or standard bus - based flat
Platform, such as PXI, VXI. In the actual project, from the bandwidth, bus delay, timing synchronization, real-time processing,
Cost and other aspects of comprehensive consideration to choose the appropriate hardware.
PXI(PCI eXtensions for an nstrumentation) is a robust, PC-based modularity
Hardware platform, is PCI bus in the field of instrument expansion, suitable for measurement and automation systems. PXI in 1997
Developed in 1998 and released in 1998, its open industry standard is managed by the PXI Systems Consortium (PXISA). The link
The Alliance consists of more than 70 companies that work together to promote PXI standards, ensure PXI interoperability, and maintain PXI regulations
Fan (https://www.pxisa.org).
VxI(VME eXtensions for Instrumentation) is another standard of the on-board instrument system
Quasi, is the VME bus in the field of instrument expansion. VXI was first released in 1987. Sponsor members of VXI are
Bustec, VTI Instruments, EADS, Keysight, NI Corporation
(https://www.vxibus.org).
The third, fourth, and fifth layers of the five-tier architecture model are software-oriented and guide the developer to design and write
Test the software. This clear hierarchy facilitates the division of testing software development tasks and improves testing
Software development efficiency, code reuse rate, robustness and scalability. The instrument driver is used to control can
A software assembly of a programming instrument in which each subroutine corresponds to a programming operation, such as open, configure, read /
Write and close. The common standard method used for instrument driving is "Plug and Play"
PnP), "Interchangeable Virtual Instrument"(Changeable Virtual Instrument Drivers IVI),
"Direct I/O". Direct one /0 is the underlying method of instrument programming, using "Standard
Commands for Programmable Instruments"(SCPI), only
Use direct I/O only when PnP and IVI are unavailable. Direct 1/0 communication beacon for modern instruments
Must be through "Virtual Instrument Software Architecture"(VISA)
API to implement. VISA is an industry standard communication protocol, whether serial port, GPIB, or
USB, read/write ASCII string VISA commands are all the same, so VISA is interface independent, which makes
Developers can program instruments with different interfaces in a single language. The instrument can be replaced while the process
The order changes very little, and PnP, IVI, and VISA are very much software-centric.
The IVI is designed to be interchangeable between instruments from multiple manufacturers without changing the code
Of. Sponsored members of the IVI Alliance are Keysight, NI, Rod Schwartz R & S
(https://www.ivifoundation.org).
Application development environment for code module development, writing specific code, such as calling instrument drivers, test
Test item development, signal processing, function analysis, etc. For a new project, a lot of time will be spent in code molds
Block development above. Common application development environments include Visual Studio, Visual C++, LabVIEW,
In the development of LabWindows/CVI, emphasis should be placed on designing highly modular and reusable code modules. Test
The management software sits at the top of the five-tier architecture model and is used to manage and execute tests. Application development environment writing
Each code module of the test management software will be a step, corresponding to a specific test item, test
The trial management software arranges these steps to form a sequence, and executes the sequence according to the final definition
Automated testing. In the process of managing these steps, it is very convenient to require adjustments in the sequence of steps. At the same time,
Code modules may be written in different languages, which is common in automated testing, so test tubes
Software needs interfaces that recognize these code modules at the same time. Automated test systems need to implement a variety of either
Tasks and functions. Some of these tasks and functions are closely related to the product, such as the configuration and calibration of specific instruments

Criterion, test item, analysis function; Others are common to most products, such as serial number tracking,

User management, test flow control, report generation, data storage, user interface updates, configuration, and prompt Windows
Mouth. In order to minimize development time and maintenance costs, as well as guarantee the life of the test system,
It is important to implement a testing strategy that separates product-level tasks from system-level tasks. If set
Properly, production-level actions are placed in code modules and done by the application development environment, while system-level actions
The operation of different test stations can be shared between different products and does not need to be redeveloped each time by the test tube
Management software takes over these tasks, and test management software is also responsible for the management and execution of code modules. This will greatly
Reduce the workload of development engineers, who can use the off-the-shelf framework provided by test management software, and more
Focus on the implementation of code modules. As you can see from the composition of the test software described in Section 1.2, in addition to the test program
Is written by the application development environment, user interface, automated testing framework, data management system, data analysis
The system is all about test management software. Some companies have written their own test actuators and distributed them
Valuable engineering resources were spent developing the test manager from scratch. The development of these test managers as well
Long time maintenance work consumes a lot of resources, resulting in the failure to fully devote to the company's core competitiveness business
Standard commercial off-the-shelf Codin software can avoid these problems, such as TestStand,
In addition to providing core functionality for the management and execution of code modules and the general operations described above,
It also facilitates parallel testing and improves test efficiency to meet the most demanding production requirements of high-volume production systems
Request; TestStand can invoke code modules written in most major application development environments, such as
LabVIEW, LabWindows/CVI, C++,.NET assembly, Visual Basic, etc.
TestStand provides an off-the-shelf architecture designed for automated testing, simplifying test software development efforts and
Improve system robustness and scalability, and these architectures are open to the project team's own needs
Request for self-customization. TestStand has many other features for test management software, as well as its functionality
Much more than the management and execution of code modules, test management is a very large category.
[Summary]
Automated testing is an industry trend that leads to improved test efficiency and test result consistency, and
Ultimately reduce costs. Automated testing is characterized by less human intervention, but not all tests are worth it
Dynamic, this needs to be evaluated, and there are some guidelines to look at. Automate testing during product development
The most important trend is to build a software-centric ecosystem, which must be passed
Standardized architecture to implement. In the test and measurement industry, the most common architecture for automated test systems is the five-tier junction
The test management software, located at the top of the model, is used to manage and execute tests through the provision of the present
The framework allows engineers to focus on the implementation of code modules, greatly saving development time.