Using the Subsystems

Measurement Function

The Measure function group has a differ- ent level of compatibility and flexibility than other commands. The parameters used with commands from the Measure group describe the signal you are going to measure. This means that the Measure functions give compatibility between in- struments, since you don’t need to know anything about the instrument you are us- ing.

MEASure?

This is the most simple query to use, but it does not offer much flexibility. The MEASure? query lets the instrument con- figure itself for an optimal measurement, starts the data acquisition, and returns the result.

￿Example:

SENDMEASure:FREQ?

This will execute a frequency measurement and the result will be sent to the controller. The instrument will select a setting for this purpose by itself, and will carry out the re- quired measurement as “well” as possible; moreover, it will automatically start the measurement and send the result to the controller.

You may add parameters to give more

details about the signal you are going to measure, for example:

SENDMEASure:FREQ?￿20￿MHz,1

Where: 20 MHz is the expected value, which can, of course, also be sent as 20E6, and 1 is the required resolution. (1 Hz)

Also the channel numbers can be speci- fied, for example:

SENDMEASure:FREQ?￿(@3)

SENDMEASure:FREQ?￿20E6,

1,(@1)

CONFigure; READ?

The CONFigure command causes the in- strument to choose an optimal setting for the specified measurement. CONFigure may cause any device setting to change. READ? starts the acquisition and returns the result.

This sequence operates in the same way as the MEASure command, but now it is possible to insert commands between CONFigure and READ? to fine tune the setting of a particular function. For exam- ple, you can change the input impedance from 1 MΩ to 50 Ω.

Measurement Function 6-9

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Fluke PM6681, PM6685 MEASure?, CONFigure READ?, SEND→ MEASureFREQ?20MHz,1, SEND→ MEASureFREQ?@3 SEND→ MEASureFREQ?20E6