Introduction to the SCPI Language
letters. Query responses will always return the short form in all upper-case letters. The following command requires a
discrete parameter for the voltage units:
[SOURce[1|2]:]VOLTage:UNIT {VPP|VRMS|DBM}
Boolean Parameters
Boolean parameters represent a single binary condition that is either true or false. For a false condition, the instrument
will accept "OFF" or "0". For a true condition, the instrument will accept "ON" or "1". When you query a boolean set-
ting, the instrument will always return "0" or "1". The following command requires a boolean parameter:
DISPlay {OFF|0|ON|1}
ASCII String Parameters
String parameters can contain virtually any set of ASCII characters. A string must begin and end with matching
quotes; either with a single quote or a double quote. You can include the quote delimiter as part of the string by typing
it twice without any characters in between. The following command uses a string parameter:
DISPlay:TEXT <
quoted string
>
For example, the following command displays the message "WAITING..." on the instrument's front panel (the quotes
are not displayed).
DISP:TEXT "WAITING..."
You can also display the same message using single quotes.
DISP:TEXT 'WAITING...'
Using Device Clear
Device Clear is an IEEE-488 low-level bus message that you can use to return the instrument to a responsive state. Dif-
ferent programming languages and IEEE-488 interface cards provide access to this capability through their own unique
commands. The status registers, the error queue, and all configuration states are left unchanged when a Device Clear
message is received.
Device Clear performs the following actions:
l
If a measurement is in progress, it is aborted.
l
The instrument returns to the trigger "idle" state.
l
The instrument's input and output buffers are cleared.
l
The instrument is prepared to accept a new command string.
The
command is the recommended method to terminate an instrument operation.
154
Agilent 33500 Series Operating and Service Guide
