Agilent Technologies 66311B Scpi Command Completion, Suffixes and Multipliers, Common Multipliers

						Introduction to Programming - 6
Suffixes and Multipliers
	Class	Suffix		Unit	Unit with Multiplier
	Current	A		ampere		MA (milliampere)
	Amplitude	V		volt		MV (millivolt)
	Time	S		second		MS (millisecond)
			Common Multipliers
		1E3		K		kilo
		1E-3		M		milli
		1E-6		U		micro

Response Data Types

Character strings returned by query statements may take either of the following forms, depending on the length of the returned string:

<CRD>	Character Response Data. Permits the return of character strings.
<AARD>	Arbitrary ASCII Response Data. Permits the return of undelimited 7-bit ASCII. This data
	type has an implied message terminator.
<SRD>	String Response Data. Returns string parameters enclosed in double quotes.

SCPI Command Completion

SCPI commands sent to the dc source are processed either sequentially or in parallel. Sequential commands finish execution before a subsequent command begins. Parallel commands allow other commands to begin executing while the parallel command is still executing. Commands that affect trigger actions are among the parallel commands.

The *WAI, *OPC, and *OPC? common commands provide different ways of indicating when all transmitted commands, including any parallel ones, have completed their operations. The syntax and parameters for these commands are described in chapter 8. Some practical considerations for using these commands are as follows:

*WAI

*OPC?

This prevents the dc source from processing subsequent commands until all pending operations are completed.

This places a 1 in the Output Queue when all pending operations have completed. Because it requires your program to read the returned value before executing the next program statement, *OPC? can be used to cause the controller to wait for commands to complete before proceeding with its program.

*OPC	This sets the OPC status bit when all pending operations have completed. Since your
	program can read this status bit on an interrupt basis, *OPC allows subsequent
	commands to be executed.
NOTE:	The trigger subsystem must be in the Idle state for the status OPC bit to be true. As far as
	triggers are concerned, OPC is false whenever the trigger subsystem is in the Initiated
	state.

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