Below we list some particular features in the syntax of the remote control commands. The general description of the SCPI command syntax can be found in section SCPI Introduction.
| Description of commands |
|
The commands are arranged in tables; all of them are arranged
in the same way. From top to bottom, the table rows contain the following
entries:
Extensive lists of default values are annexed to the command description. | |
| Order of commands | |
| The commands are arranged according to their function. The
general purpose of a command is described by the keyword in the second
level. Lower-level keywords define the command in more detail. This means
that commands with the same second-level, third-level etc. keywords are
generally grouped together in the same sections.
Example: CONFigure:POWer:FREQuency:CENTer <Frequency> Commands with the keyword POWer in the second level belong to the power measurement. The keywords in the third and fourth levels indicate that the command defines the center analyzer frequency used in the power measurement. | |
| Measurement object | The term measurement object denotes a group of remote control commands relating to the same group of measured quantities. E.g., all commands concerning the measurement of the signal power vs time form a common measurement object. |
| Combined measurements | To limit the number of remote control command and their parameters, scalar quantities of the same measurement object are always measured together and returned in lists. |
| Parameters | Many commands are supplemented by a parameter or a list of parameters. Parameters either provide alternative options (setting a or setting b or setting c ..., see special character "|"), or they form a list separated by commas (setting x,y). |
| <Par_Name> | In the command tables and lists, parameters are generally
described by a name (literal) written in angle brackets (<>). This
literal merely serves as a parameters description; in an application program
it must be replaced by one of the possible settings reported in the detailed
parameter description.
Example:
with
possible command syntax: |
| NAN | NAN (not a number) is generally used to represent missing data, e.g. if a portion of a trace has not been acquired yet. It is also returned after invalid mathematical operations such as division by zero. As defined in the SCPI standard, NAN is represented as 9.91 E 37. |
| INV | INV (invalid) is returned if a limit check is performed without defining the appropriate tolerance values. |
| Upper / lower
case |
Upper/lower case characters characterize the long and short form of the keywords in a command. The short form consists of all upper-case characters, the long form of all upper case plus all lower case characters. On the CMU, either the short form or the long form are allowed; mixed forms will generally not be recognized. Either the short form or the long form are permissible. The instrument itself does not distinguish upper case and lower case characters. |
| Special characters | |
| | | A vertical stroke in the parameter list characterizes alternative
parameter settings. Only one of the parameters separated by | must be
selected.
Example: The following command has two alternative settings:
|
| [ ] | Key words in square brackets
can be omitted when composing the command header (see chapter 5 of the
CMU manual, section "Structure of a Command"). The complete
command must be recognized by the instrument for reasons of compatibility
with the SCPI standard.
Parameters in square brackets are optional as well. They may be entered in the command or omitted. |
| { } | Braces or curly brackets enclose one or more parameters that may be included zero or more times. |
| <nr> | This symbol stands for a numeric suffix, e.g. an enumeration index for input and output connectors. |
| Lists of commands | |
| Command: | The Command column of the table contains all remote control commands arranged according to their function (configurations or measurement objects). Within a section, the commands are listed in alphabetical order. |
|
| |
| Parameters: | The Parameter column lists the parameters of the commands. |
|
| |
| Remarks: | The Remarks column gives additional information about
the commands which
Have no query form (no query) Have only a query form (query only) Can be used both as setting commands and as queries (with query, this applies to all commands belonging to none of the two preceding categories) |