Figure 9-2: Command Message Structure - Ametek 2003RP User And Programming Manual

Combining Message Units
The following command message is briefly described here, with details in subsequent
paragraphs.
Header
The basic parts of the above message are:
Message Component
Headers
Header Separator
Data
Data Separator
Message Units
Message Unit Separator
Root Specifier
Query Indicator
Message Terminator
Note: The use of compound messages such as the one shown in Figure 12-2 is
not recommended as they typically exceed the available receive buffer
length of the RP Series interface.
Headers
Headers are instructions recognized by the AC source. Headers (which are sometimes
known as "keywords") may be either in the long form or the short form.
Long Form The header is completely spelled out, such as VOLTAGE, SYSTEM, and
OUTPUT.
Short Form The header has only the first three or four letters, such as VOLT, SYST, and
OUTP.
The SCPI interface is not sensitive to case. It will recognize any case mixture, such as
VOLTAGE, VOLTage or Voltage. Short form headers result in faster program execution.
Note: In view of the 45 character receive buffer size of the RP Series, the short
form is recommended under all circumstances.
Data
SOUR:VOLT 80; FREQ 60; :CURR? <NL>
Header Message
Separator Unit
Separator

Figure 9-2: Command Message Structure

Example
SOUR VOLT FREQ CURR
The colon in SOUR:VOLT
80 60
The space in VOLT 80 and FREQ 60
VOLT 80
The semicolons in VOLT 80; and FREQ 60;
The colon in :CURR?
The question mark in CURR?
The <NL> (newline) indicator. Terminators are not part of
the SCPI syntax
Query Indicator
Message Unit
Root Message
Specifier Terminator
FREQ 60 CURR?