Keithley 2000, User Manual, Page: 130 / 280

*OPC — Operation Complete
Set the OPC bit in the standard event status register after
all pending commands are complete
Description
On power-up or when the *CLS or *RST is executed, the Model 2000 goes into the Operation
Complete Command Idle State (OCIS). In this state, no pending overlapped commands exist.
The Model 2000 has three overlapped commands:
• :INITiate
• :INITiate:CONTinuous ON
• *TRG
When you send the *OPC command, the Model 2000 exits from OCIS and enters the Oper-
ation Complete Command Active State (OCAS). In OCAS, the instrument continuously moni-
tors the No-Operation-Pending flag. After the last pending overlapped command is completed
(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 no pending com-
mand operations are present (e.g. trigger model in idle state), the Model 2000 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 will not set until the Model 2000 goes back into the idle state.
The initiate operations are not considered finished until the instrument goes into idle.
When used with the *TRG command, the OPC bit will not set until the operations associated
with the *TRG command (and the initiate command) are finished. The *TRG command is con-
sidered to be finished when the Device Action completes or when operation stops a control
source to wait for an event (see Trigger Model in this section).
To use the *OPC exclusively with the *TRG command, first force the completion of the ini-
tiate command so that only the *TRG command is pending. Do this by sending 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.
4-44 Remote Operation