Rohde & Schwarz CMW500 1201.0002K50 - SCPI Command Structure and Syntax

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are messages the controller sends to the instrument. They operate the device func-
tions and request information.
●
Device responses
are messages the instrument sends to the controller after a query. They can contain
measurement results, instrument settings and information on the instrument status.
Commands are subdivided according to two criteria:
1. According to the effect they have on the instrument:
● Setting commands
cause instrument settings such as a reset of the instrument or setting the output
level to some value.
● Queries
cause data to be provided for output, e.g. for identification of the device or polling
the active input.
2. According to their definition in standard IEEE 488.2:
● Common commands
have a function and syntax that is exactly defined in standard IEEE 488.2. Typical
tasks are the management of the standardized status registers and reset.
● Instrument-control commands
are functions that depend on the features of the instrument such as frequency
settings. A majority of these commands has also been standardized by the SCPI
consortium.
The device messages have a characteristic structure and syntax, see SCPI Command
Structure and Syntax. In the command reference chapters all commands are listed and
explained in detail.
6.2.4 SCPI Command Structure and Syntax
SCPI commands consist of a so-called header and, in most cases, one or more param-
eters. The header and the parameters are separated by a "white space" (ASCII code 0
to 9, 11 to 32 decimal, e.g. blank). The headers may consist of several mnemonics which
are separated by colons. Queries are formed by appending a question mark to the
header.
SCPI defines two command types with different syntax: common commands and instru-
ment control commands.
6.2.4.1 Common Commands
Common commands are device-independent and consist of a header preceded by an
asterisk "*" and possibly one or more parameters.
The following table shows some examples. For a comprehensive list refer to Common
Commands.
Messages