Specifications

98 Chapter 6
Retrieving Measurement Results
Retrieving the Measurement Results for Measurement Parameters 1
through 4
Trigger Input Timing When Using the :READ? Command
When executing the :READ? command while specifying its parameter (specifying the
active table), you must start measurement (provide a trigger) after changing the table to
obtain a correct measurement result.
Even if you execute the :READ? command without specifying its parameter when the
controller outputting the trigger is different from the controller executing the :READ?
command, you must provide the trigger output controller with the information on whether
the :READ? command has been executed in order to control the timing of the trigger
output appropriately (i.e., provide a trigger after the execution of the :READ? command).
As shown in Figure 6-6, you can obtain this information from the /READY_FOR_TRIG
signal of the handler interface.
Figure 6-6 Operation of the /READY_FOR_TRIG signal when executing the :READ? command
If you execute the :READ? command while the trigger system is in idle state, as shown in
Figure 6-6, after the internal processing (including change processing of the active table)
that follows the reception of the command is completed, the /READY_FOR_TRIG signal
of the handler interface changes from the High level to the Low level.
However, if continuous activation of the trigger system is turned on, as shown in Figure
6-6, when display update finishes after the completion of the measurement, the
/READY_FOR_TRIG signal changes from the High level to the Low level because the
trigger system goes into Waiting for Trigger state instead of idle state. Therefore, you
cannot obtain the information on whether the :READ? command has been executed. For
this reason, you must first turn off continuous activation of the trigger system (execute
:INIT:CONT command on page 287 specifying OFF or execute :ABOR command on
page 209).
NOTE In Figure 6-6, the :READ? command is executed after the display is updated, but it can
also be executed before the update, provided that data output has finished (the query of the
previous :READ? command has finished). Note that the internal processing still starts
after the completion of the update.