Common Child Commands

As seen in the SCPI Command Tree Viewer, most commands have lower-level commands (children). Some child commands are unique and documented in the Interactive SCPI Command Tree. Other child commands are repeated under many commands, are not shown in the Interactive SCPI Command Tree, and are known as common child commands.

 

Commands with Parameter Arguments

An example of a command with parameter arguments is the :CHANnel:COLor command, which has the arguments TCOLor1 through TCOLor16. These commands generally have the following common child commands:

:DEFault

Sets the setting to the corresponding default argument. Use the query form of this common child command to return the default argument.

:NEXT

Sets the setting to the corresponding next argument. To learn the order of the arguments, use the VSET? common query described below. There is no query form of this common child command.

:PREVious

Sets the setting to the corresponding previous argument. To learn the order of the arguments, use the VSET? common query described below. There is no query form of this common child command.

:VSET?

Returns a list of all valid arguments.

 

Commands with Numerical Arguments

An example of a command with parameter arguments is the . These commands generally have the following common child commands:

:DEFault

Sets the setting to the default value. Use the query form of this common child command to return the default value.

:MINimum

Sets the setting to its minimum possible value.

:MAXimum

Sets the setting to its maximum possible value.

:STEP

This common child command steps (increases or decreases) the current setting. An optional integer argument can be used to specify the direction (increase or decrease value) and size of the change from the current value. Generally, positive integers decrease a value and negative integer increase a value, but confirm before using as these directions can be swapped for some commands. Depending on the setting, the value of the integer either selects either a fixed change from the current value or a change according to a 1, 2, 5 sequence. For fixed changes, each time that you sent the child command :STEP -1, the change would be the same. For example, a 1ns setting would change to 2ns, 3ns, and so forth with each command. For sequence changes, if a time span is set to 1ns, sending the child command :STEP -1 would change the span to 2ns. Sending the command a second time would set the span to 5ns, and a third time to 10 ns and so forth.

 

Commands for Scalar Statistic Measurement

The :MEASure subsystem's scalar measurement commands have common child queries that return statistical measurement results and also query the validity of those values. The common child commands and queries are available for most measurements. Common statistical queries are children of each scalar measurement command and include the following:

:MEAN?

Returns the Mean measurement. It is calculated over the number of waveform acquisitions returned by the COUNt? query.

:MINimum?

Returns the Minimum measurement. It is calculated over the number of waveform acquisitions returned by the COUNt? query.

:MAXimum?

Returns the Maximum measurement. It is calculated over the number of waveform acquisitions returned by the COUNt? query.

:SDEViation?

Returns the standard deviation (Std Dev) measurement, which is only displayed in the result table for Oscilloscope Mode measurements. It is calculated over the number of waveform acquisitions returned by the COUNt? query.

:COUNt?

Returns the number of waveform acquisitions (Count) that have occurred for the parent measurement.

:STATus?

Queries the status of the common statistical measurement results. Use the :STATus:REASon? child query to determine the reason for a invalid or questionable measurement.

:STATus? Query Response

Response	Description
CORR	The measurement result is correct.
INV	The measurement result is invalid. A question mark (?) is shown in the displayed results table instead of a measurement result.
QUES	The measurement result is questionable. A question mark (?) is shown in the displayed results table next to the measurement result.

:STATus:REASon?

Queries the explanation why the :STATus? child query indicates an unsuccessful measurement. Refer to the table "Possible Common :STATus:REASon? Query Responses". If the :STATus? child query indicates a successful measurement, STATus:REASon? returns a null string.

Examples