The establishment of automatic detection system and its key technologies

The development of computer technology provides many possibilities for the establishment of automatic detection system (ATS). The typical automatic detection system mainly consists of three parts: automatic detection equipment (ATE), detection assembly (TPS) and detection environment. ATE consists of a test and measurement instrument, a host computer, a matrix switch, a communication bus, a receiver, and system software. The formation of a typical automatic detection system is shown in Figure 2.

The host computer controls the detection and measurement instruments and the operation of the TPS. System software (such as operating system, compiler, and experimental running programs) controls the working state of the inspection station, and develops and executes TPS. The TPS consists of an inspection and diagnostic program, an adapter connected to the unit under test (UUT) and ATE, and an operation manual. The inspection environment includes ATS structure description, programming and detection specification language, compiler, development tools, and standard formats describing object design requirements and detection strategy information.

Figure 2 shows the concept of a typical ATS structure
3.1 Key technologies for the establishment of modern automatic detection systems
Due to the rapid development of modern microelectronics technology and computer technology, the deep integration of detection technology and computer has caused a revolution in the field of detection instruments. The new instrument structure concept and the establishment of testing equipment are constantly updated. The key technologies for the establishment of modern testing equipment are mainly concentrated on the following points.

First, program control interface technology
How to realize the automatic connection between the detection system and the device under test is the key to realize the automation of the detection process. A computer program controlled interface unit (PIU) is an important means of solving this problem. This Program Control Interface (PIU) consists of a common set of connection points with the required buffers and demultiplexers for three basic tasks.

1. Occur, condition (such as attenuation, buffering, transforming, etc.) analog and digital excitation, and direct the excitation to the corresponding device under test;

2. Conditioning and guiding the measurement data from the corresponding device under test leads to the automatic detection system;

3. Add the programmed load to the corresponding device lead.

In short, the program control interface can control any detection system function to any device under test under the control of the program, and can complete the detection.

Second, virtual instrument technology
In the late 1980s, NI (National Instrument) proposed the concept of virtual instrument: under a certain hardware platform, using software to generate virtual panels on the screen, and under the guidance of software, signal acquisition, calculation, analysis and processing, to achieve the traditional Various functions of the instrument.

Virtual instrument is a new concept instrument that combines computer technology with instrument technology and is a major breakthrough in the concept of traditional instruments. The main functional modules of traditional instruments exist in the form of hardware (or solidified software), which is a combination of software and hardware with instrument functions. The functionality of the virtual instrument system can be flexibly configured according to the functions of the software modules and their different combinations, thus enabling and augmenting the functionality of traditional instruments.

Third, the expert system
The combination of automatic detection technology and expert system is also an important development trend in the field of automatic detection. As an important part of artificial intelligence, the expert system was produced in the 1950s and formed a complete disciplinary system of artificial intelligence in the 1980s. In the mid-1980s, the United States took the lead in introducing expert systems into the detection of airborne equipment, with good results. The combination of expert system and typical automatic detection equipment will greatly improve the ability of fault analysis and judgment, and improve the efficiency of equipment maintenance.

Fourth, on-site fault detection technology
The development trend of modern airborne equipment is that the application of microprocessors and large-scale integrated circuits is becoming more and more popular, and on-site fault detection becomes more and more important. In order to facilitate on-site maintenance, field fault detection technologies such as feature analysis, logic analysis, circuit simulation, and intrinsic diagnosis are being developed and studied. For example, using "feature analysis technology", in the relevant nodes of the circuit diagram, the "features" are marked, and the excitation is generated by the device itself. With a simple and passive detection instrument-feature analyzer, it can be quickly found on the spot. Faults, positioning to components, greatly simplifying the fault diagnosis at the repair site, effectively improving the readiness of the equipment.

V. Open, interoperable ATS implementation technology
The interoperability of ATS means that more than two systems or components can share data and information directly and efficiently. As far as the general ATS structure is concerned, its interoperability is mainly reflected in the resources that can share TPS and ATE. It can share an underlying diagnostic subsystem and can support multiple operating environments and languages. The so-called openness of the system means that its functional components adopt widely used standards or protocols, so that they can be used in different systems, can interoperate with components in other systems, and the software can be easily transplanted; the interface is also widely used. A standard, specification, or protocol, or a well-defined definition that increases, extends, and improves system performance by inserting new features.