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Section 12: Common commands
*OPC (operation complete)
This command sets the operation complete bit in the standard event status register after all pending commands
are complete.
Details
On power-up, or when *CLS or *RST is executed, the Model 6517B goes into the operation complete
command idle state (OCIS). In this state there are no pending overlapped commands. The
overlapped command used by the Model 6517B are:
:INITiate:CONTinuous ON
:INITiate
*TRG
When the *OPC command is sent, the Model 6517B exits from OCIS and enters the operation
complete command active state (OCAS). In OCAS, the instrument continuously monitors the no-
operation-pending flag. After the last pending overlapped command is complete (No-Operation-
Pending flag set to true), the operation complete (OPC) bit in the standard event status register sets,
and the instrument goes back into OCIS.
Note that the instrument always goes into OCAS when *OPC is executed. If there are no pending
command operations (for example, trigger model in idle state), the Model 6517B immediately sets the
OPC bit and returns to OCIS.
When used with the :INITiate or :INITiate:CONTinuous ON command, the OPC bit of the
standard event status register does not set until the Model 6517B goes back into the idle state. The
initiate operations are not considered finished until the instrument goes into the idle state.
The :INITiate:POFLag command is used to include or exclude the no-operation-pending flag in
the internal process of determining whether all pending operations of an initiate command are
completed.
When used with the *TRG command, the OPC bit does not set until the operations associated with
the *TRG command (and the initiate command) are finished. The *TRG command is considered to be
finished when the device action completes or when operation stops at a control source to wait for an
event (see
IEEE-488 trigger model
In order to use *OPC exclusively with the *TRG command, you must force the completion of the
initiate command so that only the *TRG command is pending. To do this, send the :ABORt command
to place the instrument in idle, which (by definition) completes the initiate command. Since continuous
initiation is on, operation continues on into the trigger model. After sending the *TRG command, the
OPC bit sets when the *TRG command is finished.
Also see
None
12-8
(on page 11-16) for more information).
Model 6517B Electrometer Reference Manual
6517B-901-01 Rev. C / August 2015
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