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12-4
After addressing the Model 2790 to talk, the returned value of 1 denotes that the bit (bit 1)
is set indicating that the :INITiate operation is now complete.
SYST:PRES
klqb
C *OPC? ⎯ Operation Complete Query
Description
When this common command is sent, an ASCII "1" will be placed in the Output Queue
after the last pending operation is completed. When the Model 2790 is then addressed to
talk, the "1" in the Output Queue will be sent to the computer.
The "1" in the Output Queue will set the MAV (Message Available) bit (B4) of the Status
Byte Register. If the corresponding bit (B4) in the Service Request Enable Register is set,
the RQS/MSS (Request for Service/Master Summary Status) bit in the Status Byte Regis-
ter will set.
When used with the Initiate Immediately command (:INITiate), a "1" will not be placed
into the Output Queue until the Model 2790 goes back into the idle state. The :INIT com-
mand operation is not considered finished until the Model 2790 goes back into the idle
state. See the description for *WAI for more information on command execution.
The execution of *OPC? is not completed until it has placed the "1" in the Output Queue.
Programming example – The following command sequence demonstrates how to use
*OPC? to signal the end of a measurement process:
SYST:PRES
INIT:CONT OFF
ABORt
TRIG:COUN 1
SAMP:COUN 5
INIT
*OPC?
Model 2790 SourceMeter
The following commands take a long time to process and may benefit from using
*OPC or *OPC?:
*RST and SYST:PRES
*RCL and *SAV
ROUT:MULT:CLOS and ROUT:MULT:OPEN — Only if the <clist> is long.
CALC2:IMM — Only when performing the standard deviation calculation on a
large buffer. A 10,000 point buffer takes around 5.75 seconds.
®
Switch System Reference Manual
' Returns 2790 to default setup.
Place a '1' in the output queue after
all pending operations are completed
' Returns 2790 to default setup.
' Disables continuous initiation.
' Aborts operation. Places 2790 in idle.
' These two commands configure the 2790
' to perform five measurements.
' Starts measurement process.
' Sends OPC? command.
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