Standard Commands for Programmable Instruments: Difference between revisions

Revision as of 05:09, 23 May 2006

Revision as of 06:59, 7 June 2006

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{{cleanup-date|February 2006}}

The '''Standard Commands for Programmable Instrumentation (SCPI)''' defines a standard set of commands to control programmable [[test and measurement]] devices in [[instrumentation]] systems.

The SCPI Standard specifies a [[command structure]] and [[syntax]] for programmable instruments control. The physical communications link, such as [[GPIB]], [[RS232]], [[USB]], [[VXIbus]] etc, is NOT defined by SCPI. SCPI also includes standard command sets for several classes of instruments, e.g. power supplies, loads, and measurement devices such as [[Voltmeters]] and [[oscilloscopes]].

SCPI commands are [[ASCII]] textual strings, which are handled well by most general purpose programing languages; including C/[[C++]], [[Visual Basic]], [[Python programming language|Python]], etc. GUI based Application Software such as Lab View and HP VEE, interact with the instruments using these commands. [[SQL]] is another well recognized textual command language, which has some advantages when [[Software Configuration Management]] (SCM) tools are used. Both [[ISO_9000]] and [[Sarbanes-Oxley Act|SOX]] require audit, history, and controlled distribution methods for production software. One low cost way to surpass most auditors expectations is to combine an SCM tool like [[SubVersion]] with a scripting language like Python that has SCPI commands embedded. Some programmers find a web viewable interface to the SCM repository helpful, like [http://www.viewvc.org/ ViewVC], and if shown to an auditor that may be worth something also. Program development with SCPI commands is generally comparable to GUI methods, however cut, past, modify of textual routines is much faster, so once a number of SCIP routines is developed productivity increases substantially.