The Design And Implementation Of Scpi Command Parsing Platform

In recent decades, with the rapid development of computer technology and electronic technology, the automated test technology has also undergone tremendous changes. A set of automated test systems often contain a few or a dozen instruments. At first, there is no uniform standard, the manufacturers have to use their own language for controlling, and programmers must learn all the commands of different instruments, which is a painful process.In order to unify the language for controlling, SCPI(Standard Commands for Programmable Instruments) standard was born. SCPI standard greatly reduces the programmer’s time of development, and the automated test technology has been improved. SCPI standard involves a lot of commands of a variety of instruments, and each instrument is only a subset of the command set. Different instrument generally has different command set, and each command set is tree structure, the paramenter very complex, which requires the SCPI parsing software can parse different instrument command sets. In order to solve common issues, the main objective of the project is to develop a SCPI parser with cross-platform, re-entrant, multi-language interface, remote control, high cohesion and low coupling.The main content of this project are below.(1) Illustrate lexical analysis and syntax analysis principles. With the compiler theory, illustrate the parsing principles and Flex and Bison which are two compiler tools. They provide a theoretical basis for the entire software.(2) Use layered architecture for the overall design. The software is designed with the purpose of generality, with the base of design pattern, and with the core of layered architecture. Layered architecture organizes the system into different levels according to different responsibilities, high cohesion and low coupling, which improve the maintainability.(3) Muli-language interface, cross-platform and re-entrant. The core code uses the standard C language, and the services layer provides Pyton language interface.(4) Provide the user interface and remote procedure call. Reference to the MVC model, the software uses GTK+interface library based on C language and PyGTK interface library based on Python language. It also supports the XML-RPC remote procedure call.According to the test result, the SCPI Command Parsing Platform based on this project is easy to use, scalability, which has achieved the project objectives.