Research on New Automotive Electronic Test Platform Based on Virtual Instrument

Abstract: In response to the increasing test requirements for automotive electronics, this paper introduces a virtual instrument-based test platform that can greatly facilitate the testing of automotive electronic products.
Key words: virtual instrument; automotive test; LabVIEW; PXI

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With the rapid development of semiconductor and software technology, automotive electronics account for a growing proportion of the automotive industry. From the comfort of the car to the stability and even the safety, automotive electronics plays a vital role and is playing an increasingly broad role. Automotive electronics manufacturers are also facing huge market challenges – improving product quality, accelerating production cycles, reducing production costs, and more.

Under such conditions, the requirements for test equipment for automotive electronic products are increasing, mainly in the following aspects.

Complex test requirements

The proportion of automotive electronics in the vehicle system and the functions realized are increasing, requiring it to have a wealth of functions; with the development of the body network based on CAN, K-Line, LIN and other buses, it is also necessary to realize a single device and a complete vehicle. Reliable real-time communication between networks. All of these require that automotive electronics products undergo complex functional and parametric testing processes before they leave the factory, thus ensuring that the products meet the functional and quality requirements specified by the vehicle manufacturer.

Strict quality management process

In addition to being able to implement test functions, the test equipment also needs to save test data, provide online analysis of test data, and easily perform production process statistics (SPC), such as measurement system analysis (MSA) and process capability index (Cpk). And thus as a data source for enterprise quality management.

Development and test cycle

At present, the cycle of launching new models by automakers is getting shorter and shorter to meet the evolving market requirements. For domestically produced and domestically produced automotive electronic products, domestic manufacturers need to establish complete test lines in a short period of time; for domestically designed automotive electronic products, test lines are often required to be tested not only before leaving the factory, but also To undertake part of the design verification task, the test system must be implemented during the product development phase, and the test equipment changes due to product improvements need to be considered in advance.

The demanding time requirements are also reflected in improving test efficiency. For mass-produced products, it is difficult to achieve time and quality requirements with traditional test equipment that has a single function and requires manual operation by the operator. Therefore, the use of automated test equipment is an indispensable condition for improving product quality and output.

Cost Control

Automotive electronics manufacturers often need to produce a variety of models and products with similar test requirements. This requires test equipment to be reusable, and it is easy to realize that multiple products share the same test line to reduce production costs. It also reduces the cost of equipment maintenance.

If the imported test equipment is completely used, the introduction and maintenance cost of the equipment is high, and the maintenance period is long. More and more manufacturers are considering to localize the imported equipment, using local suppliers or developing and maintaining it by themselves.

It can be seen from the above that in the test of automotive electronic products, the test equipment used is a software and hardware platform that needs to be quickly and flexibly customized according to the tested products, can provide rich test functions, and is convenient for local engineers to quickly develop and maintain. .

testing platform

In view of the above application requirements, this paper introduces an automotive electronic test platform based on virtual instrument technology, which can greatly facilitate the testing of automotive electronic products by various manufacturers.

Figure 1 Composition of the automotive electronic test platform

As shown in Figure 1, the test platform is built on virtual instrument technology and consists of two parts—software and hardware. The hardware uses National Instruments' (NI) PXI modular instrumentation; the software is developed using NI's LabVIEW graphical programming language and TestStand test management software.

Hardware composition

PXI is a modular instrumentation platform tailored for industrial data acquisition and automation applications. It is modular, easy to integrate, easy to handle and connect, and features such as improved device synchronization and trigger accuracy.

At the same time, PXI modular instruments are rich in products. For example, NI PXI modules are used in automotive electronics testing. There are various analog and digital signal acquisition, conditioning, signal multiplexing and matrix connection control. Bus interface, RF and arbitrary signal generators, etc. It can provide a wide range of options for automotive electronics manufacturers.

Figure 2 shows a typical set of PXI modular instruments for automotive electronics inspection, including Pent controllers based on Pentium CPUs, multiple currents and voltages consisting of digital multimeters and multiplexers and matrix switches. Test system, RF signal generator for generating car radio station signals, car radio audio analyzer and other equipment. In order to achieve automated testing, automotive electronics manufacturers typically use the bus they have, such as CAN, K-Line, etc., to open specific control commands for product state control, eliminating the need for manual intervention. Therefore, in these modular instruments, a bus controller (such as CAN, K-Line, LIN controller, etc.) is usually included. In addition, a DIO card with wide voltage input and output and optical isolation is usually configured for timing synchronization and fixture control with automated production lines.

Figure 2 Typical configuration of a PXI modular instrument

The example of Figure 2 includes various commonly used automotive electronics test instruments. In most applications, the above modular instruments can be customized, and some of them can be used to implement such as car radio (including VCD/DVD/navigation), instrument panel, driving recorder, HVAC (Heating, Ventilation and Air). Conditioning) and other products in the PCB and machine state function and parameter testing.

Software composition

As shown in Figure 3, the software part of the automotive electronic test platform consists of product drivers, test device drivers, test project implementations, test sequences (Test Sequence), and user-customized programs (such as user interface, test database management software). Part of the composition.

Product driver - used to implement program control of the product under test, usually controlled by various bus methods (such as CAN, K-Line, serial port, etc.). In order to achieve the purpose of testing without the need to manually set the product state. For a particular type of product, the parameters that need to be controlled are usually uniform and model-independent. For example, for audio testing of car radios, the parameters that need to be controlled are usually volume, band, tuning frequency, sound control, etc., regardless of model. This ensures that when developing test software for new models, there is no need to modify the functions that call them, only a new set of radio control programs that conform to the predefined interface types.

Figure 3 Software structure of the automotive electronic test platform

Test Device Drivers - Primarily refers to the drivers for PXI modular instruments to ensure proper operation of the instrument and to provide an application programming interface (API) to the developer. This part does not need to be developed by the user. The manufacturer of PXI modular instrument will provide the corresponding driver with the hardware. Usually, it also has a simple and easy-to-operate hardware management environment (such as NI MAX). Through this hardware management environment, users do not need to Programming can achieve hardware self-test, manual test, hardware configuration and other functions.

Test project implementation - a combination of product drivers and test device drivers. Automotive electronics manufacturers have specific test specifications for their different products, and the test specifications for the same type of product are usually the same. Once developed according to the manufacturer's requirements, there is no or little change to the execution of the test project when building a test line for the same product.

Test Sequence - Combine test items according to all of the manufacturer's test requirements to form a test sequence. In this platform, the test sequence is represented as a .seq file (TestStand file). All data acquisition, analysis, and recording functions are implemented in this test sequence.

User-customized programs - including user interface and test database management software. In this test platform, the user interface and test database management software are used as a common component that can be applied to test lines of various products without any modification.

The software platform has the following features:

* The same test software platform can test different models of similar products.

Since the test content and test methods of similar products are usually similar, the test project implementation part of the software only needs to be configured for different products, and can be used for all test items with the same test method, and the user does not need to rewrite the code.

* The same test sequence can be run on different test stations.

Considering the average factory time limit of the product, when selecting a PXI modular instrument, the manufacturer usually chooses multiple test stations to share the entire test time. These test stations can have the same or similar configurations, and GPIB instruments are also used on some test stations to take advantage of existing resources. If one of the test stations fails, the test software on the station can complete the exchange of the test station without rewriting the program, and only need to change the resource name of the test equipment. The PXI modular instrument and the traditional GPIB instrument have been supported in the test device driver.

* Development and maintenance time is greatly shortened

As can be seen from Figure 3, except that the product driver and test sequence to be tested will vary with the product being tested, the other parts need not be changed or changed very little after a development is completed. Therefore, in most cases, both the system integrator and the vendor's own development engineers need to focus on the specific test product control and implementation test sequence.

At the same time, due to the adoption of a unified software platform in a factory, the time spent on software maintenance is greatly reduced. The requirements of different test lines for engineers are also harmonized, thus reducing the risk caused by the flow of people.

Applications

An automobile electronics manufacturer selected the automotive electronic test platform of Shanghai Juxing Instrument Co., Ltd. to form a test line for car radio. In order to meet the requirements of Cycle Time, seven PXI test stations were used to share hundreds of test items. Two of the test stations perform PCB form tests, such as measuring voltage and current on the PCB; other test stations are tested in the form of the whole machine, such as tuning, CD/MP3, AM/FM, sound control, Write product tracking and production information, and more. As shown in Figure 4.

Figure 4 Automotive electronic test platform application examples

Different test sequences are run on each test station, but with the same user interface and test data management software.

Due to the adoption of the electronic instrument test platform based on virtual instrument technology, the test line currently undertakes three types and dozens of models of auto radio test tasks, and the maintenance of the test platform can be completed by only one engineer.

Conclusion

The automotive electronic test platform based on virtual instrument technology can effectively meet the increasingly complex test requirements, improve the development efficiency of test lines and reduce production costs, and is gradually becoming a new trend in the field of automotive electronics testing.