Fluke PM-3380B Operation Complete, 20COMMAND Reference, Query form *OPC? Response Description

4 - 20COMMAND REFERENCE

*OPC	Operation Complete
Syntax:	*OPC

Query form: *OPC?

Response: 1

Description:

The *OPC command causes the instrument to set the operation complete bit (OPC) in the standard Event Status Register (ESR), when all pending operations have been finished. When the *OPC command is received, the OPC bit is set in the *ESR register when all pending operations have been completed. The OPC bit is cleared, along with the other bits in the *ESR register, when the *ESR? query is executed.

PON URQ CME EXE DDE QYE RQC OPC

7 6 5 4 3 2 1 0

ESR

The *OPC? query places the ASCII character 1 in the output queue when all pending operations are finished. So, when the *OPC query is received, the instrument holds off the GPIB handshake as long as it is addressed as talker and there are device operations pending. Operations exist, as for example INITiate:CONTinuous ON, that never complete. Sending *OPC? during this operation prevents the instrument from responding to further program messages.

Note: The *RST command, the *CLS command, and power on cancel the effect of an *OPC command or an *OPC? query.

Restrictions:

Be careful. The GPIB controller may interrupt the program by means of timeout. So, verify first whether the timeout period is long enough to cover the operation time of the instrument.

Example:
Send → *RST;*CLS	Resets instrument clears status data.
Send → INITiate:CONTinuous ON	Continuous initiation.
Send → *OPC;*ESR?
Read ← 0	Indicates that the instrument is busy
	sweeping.
.
Send → INITiate:CONTinuous OFF	No initiation any more.
Send → *OPC;*ESR?
Read ← 1	Indicates that the instrument has
	finished sweeping.