BNC 835 Programmer Manual - Manual (Page 16)

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4 SCPI Commands
This chapter provides an introduction to SCPI programming that includes descriptions of the command
types, hierarchical command structure, data parameters, and notational conventions. Information on
BENCHTOP MICROWAVE SOURCE status system and trigger system programming is also provided.
4.1 Introduction
Standard Commands for Programmable Instruments (SCPI) is the new instrument command language
for controlling instruments that goes beyond IEEE 488.2 to address a wide variety of instrument
functions in a standard manner. SCPI promotes consistency, from the remote programming
standpoint, between instruments of the same class and between instruments with the same functional
capability. For a given measurement function such as frequency or voltage, SCPI defines the specific
command set that is available for that function. Thus, two oscilloscopes made by different
manufacturers could be used to make frequency measurements in the same way. It is also possible
for a SCPI counter to make a frequency measurement using the same commands as an oscilloscope.
SCPI commands are easy to learn, self-explanatory and account for both novice and expert
programmer’s usage. Once familiar with the organization and structure of SCPI, considerable
efficiency gains can be achieved during control program development, independent of the control
program language selected.
A key to consistent programming is the reduction of multiple ways to control similar instrument
functions. The philosophy of SCPI is for the same instrument functions to be controlled by the same
SCPI commands. To simplify learning, SCPI uses industry-standard names and terms that are
manufacturer and customer supported.
The advantage of SCPI for the ATE system programmer is reducing the time learning how to program
new SCPI instruments after programming their first SCPI instrument.
Programmers who use programming languages such as BASIC, C, FORTRAN, etc., to send
instrument commands to instruments will benefit from SCPI. Also, programmers who implement
instrument device drivers for ATE program generators and/or software instrument front panels will
benefit by SCPI’s advantages. SCPI defines instrument commands, parameters, data, and status. It is
not an application package, programming language or software intended for instrument front panel
control.
SCPI is designed to be layered on top of the hardware-independent portion of IEEE 488.2.
4.2 SCPI Command Types
SCPI commands, which are also referred to as SCPI instructions, are messages to the instrument to
perform specific tasks. The BENCHTOP MICROWAVE SOURCE command set includes:
— “Common” commands (IEE488.2 mandated commands)