Section 5: Introduction to SCPI commands
Model 2461 Interactive SourceMeter® Instrument Reference Manual
5-4
2461-901-01 A/November 2015
Queries
Some commands are queries and others have a query option. These commands have a question
mark (
?
) after the command. You can use the query to determine the present value of the parameters
of the command or to get information from the instrument.
For example, to determine what the present setting for NPLC is, you can send:
:SENSe1:RESistance:NPLCycles?
This query returns the present setting.
If the command has
MINimum
,
MAXimum
, and
DEFault
options, you can use the query command to
determine what the minimum, maximum, and default values are. In these queries, the
?
is placed
before the
MINimum
,
MAXimum
, or
DEFault
parameter. For example, to determine the default value
for NPLC, you can send:
:SENSe1:RESistance:NPLCycles? DEFault
If you send two query commands without reading the response from the first, and then attempt to
read the second response, you may receive some data from the first response followed by the
complete second response. To avoid this, do not send a query command without reading the
response. When you cannot avoid this situation, send a device clear before sending the second query
command.
When you query a Boolean option, the instrument returns a 0 or 1, even if you sent OFF or ON when
you originally sent the command.
SCPI parameters
The parameters of the SCPI commands are shown in angle brackets (
< >
). For example:
:SYSTem:BEEPer[:IMMediate] <frequency>, <time>
The type of information that you can use to replace <
frequency
> and
<time>
is defined in the
Usage section of the command description. For this example, the Usage is:
<frequency>
The frequency of the beep (20 to 8000)
<time>
The amount of time to play the tone in seconds (0.001 to 100)
For this example, you can generate an audible sound by sending:
:SYSTem:BEEPer 500, 1
Note that you do not include the angle brackets when sending the command.
Sending strings
If you are sending a string, it must begin and end with matching quotes (either single quotes or
double quotes). If you want to include a quote character as part of the string, type it twice with no
characters in between.
A command string sent to the instrument must terminate with a <new line> character. The IEEE-488.2
EOI (end-or-identify) message is interpreted as a <new line> character and can be used to terminate
a command string in place of a <new line> character. A <carriage return> followed by a <new line> is
also accepted. Command string termination will always reset the current SCPI command path to the
root level.