BNC 845-M - Manual (Page 13)

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Model 845-M Programmer’s Manual V1.1 2011
SCPI Command Types
SCPI commands, which are also referred to as SCPI instructions, are messages to the instrument to
perform specific tasks. The Model 845-M command set includes:
x “Common” commands (IEE488.2 mandated commands)
x SCPI required commands
x SCPI optional commands (per SCPI 1999.0)
x SCPI compliant commands that are unique to the Model 845-M. Not all of the commands
supported by the instrument are taken from the SCPI standard; however, their syntax
follows SCPI rules.
SCPI Command Syntax
Typical SCPI commands consist of one or more keywords, parameters, and punctuation. SCPI
command keywords can be a mixture of upper and lower case characters. Except for common
commands, each keyword has a long and a short form. In this manual, the long form is presented
with the short form in upper case and the remainder in lower case. Unrecognized versions of long
form or short form commands, or improper syntax, will generate an error.
Structure of a Command Line
A command line may consist of one or several commands. It is terminated by an EOI together with
the last data byte.
Several commands in a command line must be separated by a semicolon ";". If the next command
belongs to a different command system, the semicolon is followed by a colon. A colon ":" at the
beginning of a command marks the root node of the command tree.
If the successive commands belong to the same system, having one or several levels in common, the
command line can be abbreviated. To this end, the second command after the semicolon starts with the
level that lies below the common levels. The colon following the semicolon must be omitted in this
case.
Responses to Queries
A query is defined for each setting command unless explicitly specified otherwise. It is formed by
adding a question mark to the associated setting command. According to SCPI, the responses to queries
are partly subject to stricter rules than in standard IEEE 488.2.