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Section 12: Remote Operations
When the above message is sent, the first command word is recognized as the root command
(:STAT). When the next colon is detected, the path pointer moves down to the next command level
and executes the command. When the path pointer sees the colon after the semicolon (;), it resets
back to the root level and starts over.
Commands that are on the same command level can be executed without having to retype the
entire command path. Example:
:STAT:OPER:ENAB <NRf>; ENAB?
After the first command (:ENAB) is executed, the path pointer is at the third command level in the
structure. Since :ENAB? is also on the third level, it can be typed in without repeating the entire
path name. Notice that the leading colon for :ENAB? is not included in the program message. If a
colon were included, the path pointer would reset to the root level and expect a root command.
Because :ENAB? is not a root command, an error would occur.
Command path rules
•
Each new program message must begin with the root command, unless it is optional (for
example, [:SENSe[1]]). If the root is optional, the command word on the next level is the
root. For fastest operation, do not send optional data.
•
The colon (:) at the beginning of a program message is optional and need not be used. Note
that eliminating the first colon will result in fastest operation. Example:
:STAT:PRES = STAT:PRES
•
When a colon (:) is detected in the command path, the path is changed to the next
command level. An exception is when the path pointer detects a semicolon (;), which is
used to separate commands within the program message (see the following rule).
•
When a colon (:) that immediately follows a semicolon (;) is detected, it resets to the root
level.
•
Detection can only move down a path; it cannot be moved up a level. Executing a command
at a higher level requires that you start over at the root command.
Using common and SCPI commands in the same message
Both common commands and SCPI commands can be used in the same message if they are
separated by semicolons (;). A common command can be executed at any command level and will
not affect the path pointer. Example:
:STAT:OPER:ENAB <NRf>; *ESE <NRf>
Program message terminator (PMT)
Each program message must be terminated with an LF (line feed), EOI (end or identify), or an
LF+EOI. The bus will stop responding if your computer does not provide this termination. The
following example shows how a multiple-command program message must be terminated:
:OUTP1 ON <PMT>
Command execution rules
•
Commands execute in the order that they are presented in the program message.
•
An invalid command generates an error and is not executed.
•
Valid commands that precede an invalid command in a multiple-command program
message are executed.
•
Valid commands that follow an invalid command in a multiple-command program message
are ignored.
12-12
Model 6482 Dual-Channel Picoammeter / Voltage Source Reference Manual
Return to
Section Topics
6482-901-01 Rev. A / August 2012
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