The Development Of Virtual Electronic Test Platform For Digital Multimeter

With wide application of virtual instrument technology, computer hardware and software platform upgrades, leading instruments to the direction of multi-function, high-precision, highly integrated. Based on the numerous advantages of virtual instrument technology, aiming at the international test & measurement and the forefront of automation, Jilin University developed a set of reconfigurable electronic measurement system integrated with signal generation, data acquisition, analysis & process -- a virtual electronic test platform, mainly used in electronic measurement, industrial measurement and control, laboratory teaching and other related fields.The digital multimeter technology is almost mature, of course, this does not mean that it has been perfect. Although the performance meets the needs of the users basically, with the increasing demand of the test and measurement, the traditional digital multimeters also show a number of deficiencies. It can not display the trend of changes for the measured values directly, has poor capabilities of data processing, no storage memory, and difficulty in achieving network & remote test and so on. Particularly in the day with the rapid development of the science technology and industrial production, the demanding of electronic measurement technology and equipment has become higher and higher, the problems of traditional digital multimeters become increasingly prominent.Based on this, it is very necessary to develop a virtual digital multimeter in a reconstruction monitoring and control system of the virtual electronic test platform. By use of virtual instrument technology, combined with the advantages of the virtual edge electronic test platform developed by Jilin University, the design of virtual digital multimeter, is not only good to make up for the shortcomings of traditional digital multimeter, but also to save the development costs and shorten the development cycle-time, and maintain advantages of cost-effective for digital multimeters, as well as supply the device module board for the virtual electronic test platform, and enrich its test platform developed by theirselves, to enable it applied in electronic measurement, industrial measurement and control and laboratory teaching and other related fields better.In this paper, in accordance with the definition of mechanical specification and bus protocol in the virtual electronic test platform developed by Jilin University independently, the virtual digital multimeter is developed. The design is divided into two parts, hardware and software. Using the idea of modular in the hardware part, the virtual digital multimeter is designed for the modular measurement boards with 3U size (100mm * 160mm), connected by 96-pin Continental Connector with the system bus in a pluggable physical way. The System controller makes the module working concerted, through the USB2.0 interface communicating with computer. The main measurement part is a piece of single-chip intelligent digital multimeter integrated circuit, constituted a high cost-effective virtual digital multimeter in the most concise manner. The backplane of virtual electronic test platform provides the commands, data, address and other information needed by the virtual digital multimeter hardware. The virtual digital multimeter communicates with the controller through the production of dual-port RAM using FPGA, which establishes the communication protocols of bus system with the 1KB configuration space left, to complete the configuration register initialization, data access, equipment orders analysis and other function.The system software can be divided into two parts, the drivers and the upper application. The instrument driver is developed using VC6.0, given in the form of Dynamic Link Library, packaged I / O operations into functions, through accessing USB drives, to realize the input and output of data. The software platform is developed in the graphical virtual instrument software LabVIEW8.6, calling dynamic link library through CLF nodes directly, supplying the interface of USB driver, realizing the purposes of communication with USB controller and the control of modular instruments. In this way, the details to achieve programming are not necessary, and the flexibility and efficiency of programming are improved significantly. The graphical language LabVIEW8.6 is very applicable to design the equipment front panel to realize the intuitive visualization of measurement results.In this paper, when the design ideas of the virtual electronic test platform has been succeed, a piece of virtual digital multimeter module is developed, based on the virtual electronic test platform bus. The design maintains the advantages of low-cost, high efficiency of the traditional digital multimeter, using virtual instrument technology, which not only has the basic measurement function of the traditional ones, but also has data processing & analysis, storing, reporting and other functions, and can be used in electrical & electronic measurement and teaching experiment.