Opc? - Operation Complete Query - Keithley 2001 Operator's Manual

*OPC?  operation complete query
4.10.7
Purpose
Format
Description
Programming Example
2001-900-01 Rev. K / August 2010
60 PRINT A$
70 END
100 OUTPUT 716; ":abort"
110 OUTPUT 716; "*esr?"
120 ENTER 716; A$
130 PRINT A$
140 OUTPUT 716; ":syst:pres"
150 END
Line 10 Resets the Model 2001 to default operating conditions.
Line 20 Disables continuous initiation and aborts operation. This places the Model 2001 in
the idle state.
Line 30 Performs an immediate initiation to restart the measurement process, and then sends
the *OPC command.
Lines 40 Reads the Standard Event Status Register. The returned value of 0 denotes that the
thru 60 bit (bit 0) is not set indicating that the :INITiate operation is not complete.
Line 100 Aborts 2001 operation by placing it in the idle state.
Lines 110 Reads the Standard Event Status Register. The returned value of 1 denotes that the
thru 130 bit (bit 1) is set indicating that the :INITiate operation is now complete.
Line 140 Returns the instrument to the default operating configuration.
Place a "1" in the Output Queue after all pending operations are completed.
*OPC?
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 2001 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 Register will set.
When used with the Initiate Immediately command (:INITiate), a "1" will not be placed into the
Output Queue until the Model 2001 goes back into the idle state. The :INIT command operation
is not considered finished until the Model 2001 goes back into the idle state. See
4.10.17 (*WAI) for more information on command execution.
The execution of OPC? is not completed until it has placed the "1" in the Output Queue. For
example, ":INITiate:CONTinuous ON; *OPC?" will lock up the instrument and will require a
device clear (DCL or SDC) before it will accept any more commands.
10 OUTPUT 716; ":syst:pres"
20 OUTPUT 716; ":init:cont off; :abort"
30 OUTPUT 716; ":arm:coun 1"
40 OUTPUT 716; ":trig:coun 5; sour tim"
50 OUTPUT 716; ":init; *opc?"
IEEE-488 Reference
paragraph
4-43