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Query commands

With few exceptions, every SCPI command has a corresponding query. A command sets a

control point in the instrument; a query determines the present setting of the control point. The

query is simply the command name with a "?" attached.

Some commands are actions rather than control point settings. These commands have no que-

ry form. For example,

SENSe1:VOLTage:DC:REFerence:ACQuire

is an action command, not a setting, and so has no query form.

There are some queries that have no corresponding command. For example,

SENSe1:DATA?

causes the instrument to return the latest reading. Of course, there is no corresponding command

to send a reading value into the instrument.

Default nodes

SCPI uses the concept of default nodes. Consider the example command tree shown previ-

ously in Figure 16. What is within square brackets is not necessary to send to the instrument, but

the instrument will accept it if you send it. Consider the

:UPPer

command, which sets the mea-

surement range. To set the Mode 2002 to measure 15VDC, any of the following commands

works:

SENSe1:VOLTage:DC:RANGe:UPPer 15

SENSe:VOLTage:DC:RANGe:UPPer 15

SENSe1:VOLTage:DC:RANGe 15

VOLTage:DC:RANGe:UPPer 15

VOLTage:DC:RANGe 15

These are shown in long form, but short forms could also be used.

IEEE-488 Bus Operation 3-9

Keithley 2002 Getting Started Manual

Other manuals for Keithley 2002