*WAI — Wait-to-Continue Prevent execution of commands until previous com-
mands are completed
Description
Two types of device commands exist:
• Sequential commands — A command whose operations are allowed to finish before the
next command is executed.
• Overlapped commands — A command that allows the execution of subsequent
commands while device operations of the Overlapped command are still in progress.
Use the *WAI command to suspend the execution of subsequent commands until the device
operations of all previous Overlapped commands are finished. The *WAI command is not
needed for Sequential commands.
The Model 2010 has three overlapped commands:
• :INITiate
• :INITiate:CONTinuous ON
• *TRG
NOTE See *OPC, *OPC?, and *TRG for more information.
The :INITiate commands remove the Model 2010 from the idle state. The device operations
of :INITiate are not considered complete until the Model 2010 returns to idle. By sending the
*WAI command after the :INITiate command, all subsequent commands will not execute until
the Model 2010 goes back into idle.
The *TRG command issues a bus trigger that could be used to provide the arm, scan, and
measure events for the Trigger Model. By sending the *WAI command after the *TRG
command, subsequent commands will not be executed until the pointer for the Trigger Model
has finished moving in response to *TRG and has settled at its next state.
Program Fragment
PRINT #1, "output 02; :syst:pres" 'Select defaults
PRINT #1, "output 02; :init:cont off;:abort"
'Place 2010 in idle
PRINT #1, "output 02; :trig:coun 1;sour tim"
'Program for 30 measurements and
'then stop (idle)
PRINT #1, "output 02; :samp:coun 30"
PRINT #1, "output 02;:init; *wai" 'Start measurements and send *wait
PRINT #1, "output 02; :data?" 'Query a reading
PRINT #1, "enter 02" 'Get reading after 2010 goes into
'idle
LINE INPUT #2, a$ 'Read the reading
PRINT a$ 'Display the reading
4-46 Remote Operation
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