Fluke PM-3384B, PM-3380B, PM-3390B, PM-3370B READFREQuency?, Starts Acquisition Returns, Etc

USING THE COMBISCOPE INSTRUMENTS				3 - 15
READ:FREQuency?	Starts the	acquisition and	returns the	measured
	frequency.
READ:FREQuency?	Starts a	next acquisition	and returns	the new
	frequency result.
READ:FREQuency?	Etc.

3.3.6Multiple characteristics from a single acquisition.

It is often necessary to determine several signal characteristics from the last acquired waveform. Starting a new acquisition, as READ? and MEASure? do, is undesired. For that purpose, READ? is broken down into two additional instructions, which are the INITiate[:IMMediate] command and the FETCh? query. Executing this sequence of instructions is equivalent to READ?. The INITiate[:IMMediate] command starts the acquisition. FETCh? determines the requested signal characteristic and returns the result. This concept allows you to perform several different FETCh? queries on a single set of acquisition data.

Example:

MEASure:AC?Configures the instrument to measure the RMS value of the AC component of the signal at input channel 1, starts the acquisition, and returns the desired result.

FETCh:FREQuency? Determines and returns the frequency of the signal that is acquired by the preceding MEASure? query.

FETCh:RISE:TIME? Uses default parameters to determine and return the rise time of the first pulse.

As distinct from the READ? query, defaulting the measure function part of the FETCh? query, causes the CombiScope instrument to return the characteristic that was requested with the last executed FETCh?, READ? or MEASure? query. For this reason, the measure function should always be explicitly specified in the header of the FETCh? query.