Remote Control
R&S
®
CMW500
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User Manual 1173.9463.02 ─ 02
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
. 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
Messages
