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3.2 Commands
Command
There are three types of commands (program headers)
that are sent from the controller to the instrument.
They differ in their program header formats.
Common Command Header
Commands that are defined in the IEEE 488.2-1992
are called common commands. The header format of
a common command is shown below. An asterisk (*)
is always placed in the beginning of a command.
<Mnemonic>
*
?
An example of a common command: *CLS
Compound Header
Dedicated commands used by the instrument are
classified and arranged in a hierarchy according to
their functions. The format of a compound header is
shown below. A colon (:) must be used to specify a
lower hierarchy.
:
:
<Mnemonic>
An example of a compound header:
MEASURE:FUNCTION
Simple Header
These commands are functionally independent and do
not have a hierarchy. The format of a simple header is
shown below.
:
<Mnemonic>
An example of a simple header: START
Note
A <mnemonic> is a character string made up of alphanumeric
characters.
IM 704510-17E
?
?
When Concatenating Commands
• Command Group
A command group is a group of commands that
have common compound headers arranged in a
hierarchy. A command group may contain sub-
groups.
Example
Group of commands related to sampling
:SAMPLE?
:SAMPLE:GATE?
:SAMPLE:GATE:MODE
:SAMPLE:GATE:EVENTSIZE
:SAMPLE:GATE:POLARITY
:SAMPLE:GATE:TIME
:SAMPLE:INTERVAL
:SAMPLE:ARMING:SOURCE
:SAMPLE:ARMING:DELAY:MODE
:SAMPLE:ARMING:DELAY:TIME
• When Concatenating Commands of the Same
Group
The instrument stores the hierarchical level of the
command that is currently being executed, and
performs analysis on the assumption that the next
command sent will also belong to the same level.
Therefore, common header sections can be omitted
for commands belonging to the same group.
Example
:INPUT:ACHANNEL:COUPLING AC;
IMPEDANCE I50<PMT>
• When Concatenating Commands of Different
Groups
If the following command does not belong to the
same group, a colon (:) is placed in front of the
header.
:MEASURE:MODE TSTAMP;:DISPLAY:
Example
ITEM LIST<PMT>
• When Concatenating Simple Headers
If a simple header follows another command, a
colon (:) is placed in front of the simple header.
Example
:MEASURE:MODE TSTAMP;:
START<PMT>
• When Concatenating Common Commands
Common commands that are defined in the IEEE
488.2-1992 are independent of hierarchy. Colons
(:) are not needed before a common command.
Example
:MEASURE:MODE TSTAMP;*CLS;
FUNCTION PERIOD,A<PMT>
3.2 Commands
3
3-3
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