The Design Of SCPI Interpreter

With the rapid development of the computer technology, the instrumentindustry has been experiencing a dramatic change, the manual operation instrumentchanging to the automatic measurement with the computer. Leading equipmentmanufacturers jointly study and formulate the standard program-controlledcommands named SCPI (Standard Commands for Programmable Instruments) forall kinds of the program-controlled instruments. As an important command standardfor remote control testing instruments, SCPI has been wildly used in developingand testing of the intelligent instruments. The research of the thesis is based on theproject “The Management Software of SCPI” from institutes, which resolvesmanagement issues of SCPI in military electronic equipment testing system. As animportant part of the project, the research of the thesis can use SCPI command tooperate and control testing instruments. So the design of SCPI interpreter is thecore content of the project.SCPI achieves program-controlled equipments standardization for devicesinformation, whose overall goal is to shorten the procedures and time of developingthe automatic test equipment, at the same time, protects both the hardware andsoftware investment of the equipment manufacturers and users, and provides a widerange of code environmental for the instrument control and data transmission.This paper first introduces mnemonic, syntax and style, instrument model,hierarchy, common command and instrument-control command of SCPI, which arethe basis for research. Second, in order to get efficient data storage and querymechanism, the project builds the database file of SCPI commands according to thestructural characteristics of SCPI. The project selects the MFC ODBC databasetechnology according to corresponding query mechanism to access the commanddatabase file and complete the query capabilities of command. Third, the projectcreates the command tree of SCPI based on CTreeCtrl control in VC++, queries thetree of SCPI commands and gets the full path of SCPI subcommand. Making use ofthe query mechanism of ODBC database, a program-controlled instrumentcommand that associated with the SCPI subcommand was found. Finally, accordingto serial communication protocol of multi-channel temperature loopback device asa program-controlled instrument, the project send the SCPI commands to operate and control temperature loopback device and read the data from the temperatureloopback device, and complete software testing.The SCPI interpreter is designed based on VC++6.0，achieved interpreterfunction for command that user input SCPI command then operate and controlprogram-controlled instrument. According to user requirements, the networking ofthe testing system is easy to realize through modifying and expanding the commanddatabase.