REMOTE CONTROL (GPIB & RS-232) 5–4
FREQ 0.1E4
FREQ 1k
are all valid ways of setting a frequency of 1kHz.
3) Integer
A single integer number. Often used to indicate a Boolean state.
For example:
RANGE 1
will select range 1.
If invalid data is supplied then a command error will be generated. If data is supplied but
the instrument is not able to apply the setting, an execution error will be generated. If the
instrument is unable to exactly comply with the command and can only apply the nearest
available, a device specific error is generated. Details of these error codes can be found in
Figure 5-6.
5.2.4.2 Hierarchical Commands
As described in the previous section, SCPI uses a command tree to simplify device
programming. This structure is similar to the directory structure used on most computers. To
access a specific command in a specific mode the user must supply the ‘path’ to reach that
particular command within the tree.
When the unit is powered up the initial path is ‘root’ which is the top level from which all paths
must start.
Note that common commands (which by convention always start with the ‘*’ character) are not
part of the tree and can be accessed regardless of the current path.
So to select the impedance measurement function in deviation mode, the path must describe the
command tree as below:
The ‘:’ character is used as the path separator so the command string will be:
:DEV:FUNC:Z
Note that the string starts with ‘:’. This tells the instrument to start from the ‘root’ path.
Whenever a terminator is reached (line-feed and/or EOI) the path is reset to the root path, so
each new GPIB command string must state the full path in order to work correctly, for example:
To set a measurement frequency of 1kHz at a level of 1.0V, the following string can be used:
:MEAS:FREQ 1k;LEV 1.0V <line-feed>
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