Keysight Technologies 86120B, User Manual

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Programming
Reviewing SCPI Syntax Rules
Querying data
Data is requested from the instrument using a query. Queries can be used to find out
how the instrument is currently configured. They are also used to get results of mea-
surements made by the instrument, with the query actually activating the measure-
ment. String responses are returned as upper-case letters.
Queries usually take the form of a command followed by a question mark (?). After
receiving a query, the instrument places the answer in its output queue. The answer
remains in the output queue until it is read or another command is issued. For exam-
ple, the query
OUTPUT 720;”:CALCULATE2:POINTS?”
places the number of points in the data set in the output queue. In HP BASIC, the
controller input statement:
ENTER 720;Range
passes the value across the bus to the controller and places it in the variable Range.
A newline character is appended to the response.
Sending another command or query before reading the result of a query causes the
output queue to be cleared and the current response to be lost. This also generates an
error in the error queue.
The output of the instrument may be numeric or character data depending on what is
queried. Refer to the specific commands for the formats and types of data returned
from queries.
You can send multiple queries to the instrument within a single program message,
but you must also read them back within a single program message. This can be
accomplished by either reading them back into a string variable or into multiple
numeric variables. When you read the result of multiple queries into string vari-
ables, each response is separated by a semicolon.