Design And Application Of Gpib Automatic Testing Based On Visa Function Lib

Virtual instrument software architecture VISA is a collection of the standardized I/O function lib and its correlative criterion. It can execute special function of instrument bus in the computer system and connect the computer with instrument on software level so as to operate on the instrument. As the general I/O standard, VISA faces the equipment but interface bus. Therefore comparing with existing I/O interface software, the special advantage is that VISA has formed a screen between users and the operation on hardware interfaces. It is independent of the hardware equipment, the interface, the operating system and the program language to call VISA functions. It is a set of existing I/O interface software. But as a standard, VISA only publicized the prototype of each function and how these functions are realized concretely was not explained.The dissertation presented detailedly the development of I/O function lib, which we have self-owned intellectual property rights, based on USB-GPIB interface controller that was also developed by ourselves. It is divided into six aspects as the following: (1) Through the massive experiments, the standard I/O function lib based on VISA was deeply analyzed including the structure level and function characteristic.(2) Based on USB-GPIB interface controller which was developed by us, VISA function lib was designed and concrete solutions were also given to communication protocol, management of resources, formatted input/output, exclusive access among resources, resource attributes and error processing on the essential technology in realization of VISA.(3) Five kinds of standard functions of VISA lib were completed,which have been established,debugging and testing including resource management class, basic I/O class, formatted I/O class, GPIB interface function class and VISA control and management class. The VISA lib involves twenty-seven VISA standard functions, fifteen SICL control functions and ten private functions. The VISA dynamic link library based on the foregoing work was completed.(4) Compared to domestic products, the VISA interactive debugging equipment has been developed firstly with the use of VB and Delphi, in order to establish USB-GPIB automatic testing system and debugging a GPIB system.(5) Through the research and analysis for the function characteristic of VISA lib, the ways were proposed that USB-GPIB interface controller and VISA function lib were applied into multiple domains such as long-distance instrument control in Ethernet, spectrum analysis and data management automation. The programs have been designed and compiled for the foregoing application to prove the ways doable and correct.(6) Through the research and analysis for the function characteristic of The VISA COM domestic and broad, the method was study that the VISA lib was encapsulated according to the object-oriented programming thought. Compared to domestic products, VISA COM was successfully developed for the first time, in order to enhance the application ability of VISA in the network environment.The USB-GPIB controller and its VISA standard function lib have been connected, debugged and mended with more than ten GPIB equipments domestic and broad, such as the Digital Multimeter, the spectrum analyzer and the network analyzer produced by Agilent Corporation and FLUCK Corporation’s calibrator. The product has been also applied into actual testing system. Now it has been proven design reasonable, performance reliable, function consummates and operates convenient as a commercialization product.