Specifications

Chapter 16 293

Command Reference

:READ?

16. Command Reference

:READ?

Syntax :READ? [<numeric>]

Description When the instrument is configured to use an internal, manual or external trigger source

(that is, after you have issued the :TRIG:SOUR command by specifying “INT”, “MAN”

or “EXT”), issuing this command without the parameter sets the trigger system into trigger

wait state. Then this command returns the measurement data when the instrument is

triggered and has completed the measurement cycle.

When the instrument is configured to use an internal, manual or external trigger source,

issuing this command with the parameter sets the active table to the number specified by

the parameter. Then the 4287A is operated as described above. In other words, issuing this

command with the parameter causes the same operation as when the :SOUR:LIST:TABL

command is issued, and then the :READ? command is issued without the parameter.

When the instrument is configured to use the GPIB/LAN trigger source (that is, after you

have issued the :TRIG:SOUR command by specifying “BUS”), this command fails and an

error is generated. This is because issuing the command would prevent the instrument from

being triggered. (Query only)

NOTE When the instrument is configured to use a manual or external trigger source, it does not

accept any additional command until it is triggered from the external source. To exit from

this state without triggering the instrument from the external source, you must send the

Device Clear command (“CLEAR” statement in HP BASIC) to abort query processing.

Parameters This is an optional parameter. You don’t have to specify the parameter if you don’t intend

to change the active table every measurement.

If your specified parameter is beyond the valid range, the command fails and an error is

generated.

Query response Same as the :FETC? command. See the description of :FETC?.