Model 7002Switch System Instruction Manual - Advanced Test ...

IEEE-488 Reference5.10.6 *OPC ⎯ operation completePurposeTo set the Operation Complete bit in the Standard Event Status Register after all overlappedcommands are complete.Format*OPCDescriptionOn power-up, or when *CLS or *RST is executed, the Model 7002 goes into the OperationComplete Command Idle State (OCIS). In this state there are no pending overlapped commands.There are three overlapped commands used by the Model 7002::INITiate:INITiate:CONTinuous ON*TRGWhen the *OPC command is sent, the Model 7002 exits from OCIS and enters the OperationComplete Command Active State (OCAS). In OCAS, the instrument continuously monitors theNo-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 StandardEvent 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 pendingcommand operations (e.g. trigger model in idle state), the Model 7002 immediately sets theOPC bit and returns to OCIS.When used with the :INITiate or :INITiate:CONTinuous ON command, the OPC bit of the StandardEvent Status Register will not set until the Model 7002 goes back into the idle state. Theinitiate operations are not considered finished until the instrument goes into the idle state.When used with the *TRG command, the OPC bit will not set until the operations associatedwith the *TRG command (and the initiate command) are finished. The *TRG command is consideredto be finished when the Device Action completes or when operation stops at a controlsource to wait for an event (see Trigger Model in paragraph 5.7).In order to use *OPC exclusively with the *TRG command you will have to first force the completionof the initiate command so that only the *TRG command is pending. To do this, use the:INITiate:CONTinuous ON command to start the scan and then send the :ABORT command.The abort command places the instrument in the idle layer, which (by definition) completes theinitiate command. Since continuous initiation is on, operation will continue on into the TriggerModel. After sending the *TRG command, the OPC bit will set when the *TRG command isfinished.5-50