Keithley 2790, Reference Manual

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12-8 Model 2790 SourceMeter
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I *WAI — Wait-to-Continue
Prevent execution of commands until
previous commands 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 2790 has three overlapped commands:
•
:
INITiate
• :INITiate:CONTinuous ON
• *TRG
klqb
See *OPC, *OPC?, and *TRG for more information.
The INITiate commands remove the Model 2790 from the idle state. The device opera-
tions of :INITiate are not considered complete until the Model 2790 returns to idle. By
sending the *WAI command after the INITiate command, all subsequent commands will
not execute until the Model 2790 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.
Programming example – The following command sequence shows how to use the *WAI
command to allow the Model 2790 to wait for the programmed measurements to be com-
pleted before requesting a reading.
SYST:PRES ‘ Returns 2790 to default setup.
INIT:CONT OFF ‘ Disables continuous initiation.
ABORt ‘ Aborts operation. Places 2790 in idle.
TRIG:COUN 1 ‘ These two commands configure the 2790
SAMP:COUN 30 ‘ to perform 30 measurements.
INIT ‘ Starts measurement process.
*WAI ‘ Sends the WAI command. Program waits for 2790 to go
‘ into idle before executing next command.
DATA? ‘ Requests one reading.