User and Programming Manual - Rev H
California Instruments
May 2000
P Series
58
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Read back all the results of a query before sending another command to the AC source.
Otherwise a Query Error will occur and the unreturned data will be lost.
12.4 Structure of a SCPI Message
SCPI messages consist of one or more message units ending in a message terminator. The
terminator is not part of the syntax, but implicit in the way your programming language
indicates the end of a line (such as a newline or end-of-line character).
12.4.1 The Message Unit
The simplest SCPI command is a single message unit consisting of a command header (or
keyword) followed by a message terminator.
FREQuency?<newline>
VOLTage?<newline>
The message unit may include a parameter after the header. The parameter usually is
numeric:
VOLTage 20<newline>
OUTPut 1<newline>
12.4.2 Combining Message Units
The following command message is briefly described here, with details in subsequent
paragraphs.
Data
Query Indicator
Message Unit
Header
SOUR:VOLT 80; FREQ 60; :CURR? <NL>
Header Message
Root
Message
Separator Unit Specifier Terminator
Separator
Figure 12-2: Command Message Structure
