SCPI Introduction
Copyright © Itech Electronic Co., Ltd. 15
ROOT
:CURRent [:LEVel]
:PROTection [:LEVel]
:DELay
:STATus :OPERatition [:EVENt]
:CONDition
Partial Command Tree
2.2.1 Multiple Commands in a Message
Multiple SCPI commands can be combined and sent as a single message with
one message terminator. There are two important considerations when sending
several commands within a single message:
Use a semicolon to separate commands within a message.
There is an implied header path that affects how commands are interpreted
by the electronic load.
The header path can be thought of as a string that gets inserted before each
command within a message.For the first command in a message, the header
path is a null string. For each subsequent command the header path is defined
as the characters that make up the headers of the previous command in the
message up to and including the last colon separator. An example of a
message with two commands is:
CURR:LEV 3;PROT:STAT OFF, which shows the
use of the semicolon separating the two commands, and also illustrates the
header path concept. Note that with the second command, the leading header
"CURR" was omitted because after the "CURR:LEV 3" command, the header
path became defined as "CURR" and thus the instrument interpreted the
second command as:
CURR:PROT:STAT OFF
In fact, it would have been syntactically incorrect to include the "CURR"
explicitly in the second command, since the result after combining it with the
header path would be: CURR:CURR:PROT:STAT OFF,
which is incorrect.
2.2.2 Moving Among Subsystems
In order to combine commands from different subsystems, you need to be able
to reset the header path to a null string within a message. You do this by
beginning the command with a colon (:), which discards any previous header
path. For example, you could clear the output protection and check the status of
the Operation Condition register in one message by using a root specifier as
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