Tektronix WCA230A, Programmer'S Manual

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Command Syntax
WCA230A & WCA280A Programmer Manual
2- 3
SCPI commands are created by stringing together the nodes of a subsystem
hierarchy and separating each node by a colon.
In Figure 2--1, TRIGger is the root node and SEQuence, LEVel, POLarity, and
SOURce are lower-level nodes. To create a SCPI command, start with the root
node TRIGger and move down the tree structure adding nodes until you reach
the end of a branch. Most commands and some queries have parameters; you
must include a value for these parameters. If you specify a parameter value that
is out of range, the parameter will be set to a default value. The command
descriptions, which start on page 2--39, list the valid values for all parameters.
For example,
TRIGger:SEQuence:SOURce EXT
is a valid SCPI command
created from the hierarchy tree in Figure 2--1.
To create a query, start at the root node of a tree structure, move down to the end
of a branch, and add a question mark.
TRIGger:SEQuence:SOURce?
is an
example of a valid SCPI query using the hierarchy tree in Figure 2--1.
The query causes the analyzer to return information about its status or settings.
When a query is sent to the analyzer, only the values are returned. When the
returned value is a mnemonic, it is noted in abbreviated format, as shown in
Table 2--2.
Table 2- 2: Query response examples
Query Response
:DISPlay:OVIew:SGRam:X:SPAN? 10.0E+6
:SENSe:AVERage:TYPE? RMS
A few queries also initiate an operation action before returning information. For
example, the *CAL? query runs a calibration.
Creating Commands
Creating Queries
Query Responses