Construction of RWR automatic test and diagnosis system based on VXI bus technology

0 Introduction

With the application of new electronic devices in radar warning equipment (RWR), its intelligence level is getting higher and higher, and its structure is becoming more and more complex and compact, which greatly increases the difficulty of testing and diagnosis. In actual use, in order to ensure the effective function of RWR, it is required to provide technical support mainly based on performance testing and fault diagnosis: it can test various parameters of the equipment quickly, accurately and with high precision, and provide guiding suggestions for troubleshooting. Therefore, it is of great significance to research and develop a test and diagnosis system suitable for the technical support requirements of RWR.

This paper uses VXI bus technology to build an RWR automatic test and diagnosis system. The system is a system with industrial computer as the core, VXI bus instrument as the support, adapter as the bridge, integrating control, data acquisition and processing, storage, analysis, display and printing. It can not only complete the test of the performance and function of the RWR, but also perform qualitative and quantitative detection and fault diagnosis on each line replaceable unit (LRU) separately.

1 System Hardware Structure

The hardware design idea of ​​this system is: select the VXI bus structure according to the principles of modularization, generalization and standardization, determine the type of test resources according to the test requirements, select the resource model according to the cost-effectiveness requirements, and give priority to familiar hardware products considering the short development cycle requirements. Under the guidance of the above ideas, the design system hardware structure is shown in Figure 1.



1.1 Measurement and Control Computer

The measurement and control computer (TCC) is the core of the system. This system uses Advantech military reinforced notebooks, and peripherals include Agilent's USB/GPIB interface converter 82357A, mouse, printer, UPS power supply, etc.

1.2 VXI bus instruments and modules

VXI instruments have the characteristics of high speed, high precision, easy expansion, small size, and light weight, so they have been widely used in the field of automatic test equipment (ATE). The VXI instruments of this system adopt the external controller mode. Therefore, the VXI bus instruments include: 13-slot C-size VXI mainframe 1261B, used to carry all VXI modules and provide power supply and control interface; IEEE1394 VXI zero-slot controller E8491B, used for VXI zero-slot and resource management, it communicates with TCC through IEEE1394 bus; 48-channel TTL digital I/O module VM1548, used for providing/measuring the input/output TTL level signal of the RWR under test and controlling the relay in the adapter; 4-channel serial port interface module VM6068, used for RS 422 communication signal simulation and reception; matrix switch E1466A is used to complete the switching of various measurement channels; 6.5-digit multimeter E1412A is used to measure various voltages and resistances; oscilloscope E1428A is used to measure various video pulses and SA2U synchronization signal sampling; coaxial switch SMP6101 is used to complete the switching of video signals; pulse/code generator E8311A is used to simulate the video pulses of various pulse radars; arbitrary function generator E1445A is used to generate sawtooth wave signals to drive the power amplifier circuit to output X, Y deflection signals with certain current driving capabilities.

1.3 GPIB bus instruments and accessories

Since there are relatively few high-power, ultra-high frequency VXI bus instruments, the system uses GPIB bus instruments as a supplement to meet the special needs of the device under test. The GPIB bus instruments of this system include: microwave signal source E8257D and microwave switch 8766K, horn antenna accessories, used to simulate various radar signals; turntable controller and turntable, set turntable parameters (speed, direction, rotation) to rotate the device under test to achieve the purpose of measuring RWR direction finding error.

1.4 Interface adapter

The interface adapter (TUA) is a pre-processing and switching device for the RWR signal under test, completing the mechanical and electrical connection between the device under test and the VXI bus instrument, GPIB bus instrument and accessory interface. The interface adapter is mainly composed of power supply components, signal conditioning board, resource allocation board, relay control board, etc. The power supply component converts 220 V/50 Hz AC into 28 V/3 A, 5 V/5 A, 6 V/0.5 A, 12 V/1 A, 15 V/0.5 A, 24 V/0.5 A, -6 V/0.5 A, -12 V/1 A, -15 V/0.5 A DC power supply to provide power to the RWR, microwave switch, etc. under test; the signal conditioning board mainly completes the amplification, matching, and conditioning of various VXI module resource signals; the resource allocation board allocates the resources of each VXI module to the DUT interface and signal conditioning board on the front panel of the adapter. The relay control board mainly completes the power supply control of the seven LRUs. [page]

1.5 Connection cables

There are four types of connection cables: the first type is the instrument control cable, such as IEEE1394 bus cable, GPIB bus cable, etc.; the second type is the input/output cable between the instrument and the interface adapter; the third type is the test cable connecting the interface adapter and the device under test; the fourth type is the accessory connection cable.

2 System software design

The system software part is designed with Windows XP as the operating system, GPTS 3.0 as the test program development and operation environment, and INCON 2.0 as the fault diagnosis and reasoning platform. It is responsible for completing the management of the test and diagnosis process, the operation of the program, the analysis of the data, the recording of the results, etc. The system software adopts a modular design, mainly including: system management module, system self-test module, performance function test module, fault diagnosis module, instrument driver module, database and knowledge base module, interactive operation manual module, etc. Its software structure is shown in Figure 2.



System management module: responsible for the identity authentication, management, status setting, scheduling of each program module, etc. of the system user, and is the management center of each functional module.

System self-check module: mainly completes system construction inspection, instrument self-check control, signal transfer center logic reliability and accuracy inspection, and detection interface connection reliability inspection.

Performance function test module: completes the test of RWR, whole machine and each LRU performance and functional indicators. It is an important factor in determining whether the test meets the requirements and whether the test results are accurate and reliable. The performance function test module is written in the signal-oriented ATLAS standardized test language. The TPS (test program set) is developed in a more standardized manner, with good versatility and compatibility, and is independent of the hardware platform.

Instrument driver module: a bridge between the test program and the system physical instrument. Mainly includes: instrument-like virtual resource driver, instrument-like ACM driver, and IVI instrument driver. The instrument-like virtual resource driver is used to control the common behavior of a certain type of instrument (such as DMM-like instrument). It is a software module in the form of DLL implemented by COM. Its main function is to convert the description of the test requirements of the ATLAS program into the settings of the instrument. The instrument-like ACM driver is a software module for a certain type of instrument. It passes the settings of the instrument-like virtual resource driver to the IVI driver layer. IVI driver is used to realize interaction with physical instruments, and directly interacts with hardware through VISA software I/O layer, with COM and C modes.

Fault diagnosis module: used for fault diagnosis and location of each LRU of RWR, and gives expert advice on maintenance. The fault diagnosis module adopts reasoning methods based on neural network, fuzzy logic and expert system to realize intelligent fault diagnosis.

Database and knowledge base module: used to save various data used by the software, including domain knowledge, test data and analysis results in expert system. The database in the system includes expert knowledge base, measurement result database, diagnosis result database, user authority database, system log database, etc.

Interactive operation manual module: used for user self-training, consolidation learning, information query, easy to use and flexible. [page]

3 System test diagnosis process

According to the characteristics of RWR and user needs, this system adopts the parallel hierarchical testing concept. Users can choose to perform whole machine performance test or LRU test according to their needs. The first level performs performance and function tests and diagnosis on the whole machine, and locates the fault to the LRU; the second level performs function and performance tests and diagnosis on the LRU, and locates the fault to the field replaceable unit (SRU). The LRU interface information is rich and can be located to the functional circuit, and some can be located to the component level. Figure 3 shows the test and diagnosis process of RWR.



The test and diagnosis process is as follows:

(1) Turn on the machine and verify the user's identity.

(2) System self-test. After the system self-test passes, enter the RWR test environment, and the user can choose to perform the whole machine index test or LRU test. If the system self-test fails, start the system self-calibration function to perform software calibration on the system. After the calibration is completed, perform the system self-test again.

(3) If the user chooses the whole machine test, the system will prompt the user to connect the whole machine test cable.

(4) Start the BIT (built-in test) function of RWR and enter the self-test results into the system.

(5) After the RWR self-test passes, the user can flexibly select the whole machine test items and test times. After setting, the system will automatically measure them one by one.

(6) Determine whether the RWR performance meets the requirements based on the whole machine index test results. If the indicators meet the requirements, the conclusion that the RWR function and performance are normal is given, the test results are output, and the test ends; if the indicators do not meet the requirements, the LRU test is performed.

(7) If the RWR and BIT reports are faulty in step (4), the whole machine test is skipped and the LRU test is performed directly. The LRU test includes tests on the direction finding receiver, continuous wave receiver, command signal receiver, digital analyzer, character display, control box, power supply filter, etc.

(8) When testing the direction finding receiver, the user can flexibly select the test items and the number of tests. After setting, the system automatically measures one by one. If the indicators are normal, the conclusion that the direction finding receiver is normal is given and the test ends; if the indicators are abnormal, the corresponding fault diagnosis software is called in for diagnosis, and the diagnosis results and expert advice for repair are given.

(9) Other LRU test methods are the same as (8).

4 Conclusion

The design of the RWR automatic test and diagnosis system based on the VXI bus follows the design ideas of universality, standardization, and modularity from the establishment of technical solutions, hardware integration to software development. It has strong universality and openness, and can be expanded according to user needs. If you want to test and diagnose other similar objects under test, you only need to design the corresponding interface adapter and write the corresponding test and fault diagnosis program. Practice shows that the system has a friendly user interface and is easy to operate. It can quickly and accurately test various functions and performance parameters of RWR, and diagnose faults based on test data, and then provide maintenance strategies, which greatly improves the efficiency of testing and troubleshooting, saves maintenance costs, and has high military and economic value.