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.
For example, the :TIMebase:SCALe command has the following common child commands:
:TIMebase:SCALe 1E-9 :TIMebase:SCALe:DEFault :TIMebase:SCALe:MAXimum :TIMebase:SCALe:MINimum :TIMebase:SCALe:STEP
Commands with ON/OFF Arguments
An example of a command with ON/OFF arguments is the :DISPlay:GRID:STATe command, which has the arguments {{ON | 1} | {OFF | 0}}. These commands generally have the following common child command:
:TOGGle- Sets to OFF if currently ON or to ON if currently OFF.
Commands with Parameter Arguments
An example of a command with parameter arguments is the :CHANnel:COLor command, which has the arguments TCOLor1 through TCOLor48. 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 :TIMebase:SCALe. 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 -1would 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.