Query Syntax

:WAVeform:XYFormat:FLOat:YDATa?

Description

Returns the x-axis data in for XY-formatted data. The data is sent point-by-point starting from the graticule's left side and progressing to the right side. Use the :WAVeform:XYFormat:FLOat:XDATa? query to return the y-axis data. Use the :WAVeform:XYFormat:POINts? query to return the number of points contained in the array. The XY-format data format is designed for waveforms that have been sampled using unequal time separations between adjacent data points. Unequal time separations occurs with pattern waveforms or when using a precision timebase.

Returned Data Type

The :WAVeform:XYFormat:FLOat:YDATa? query returns float (4 bytes) values as binary definite-length block data queries binary definite-length block data queries binary definite-length block data queries. You must specify this data type in your program language's command that you use to query the data. The specifier for this data type in your programming language will likely be "f" and it is identified in this example with red text. Confirm this with your programming language's documentation. The following is an example of the command used in Python using pyvisa.

Flex.read_termination = ''
Flex.write_termination = ''
endianness = Flex.query(':SYSTem:BORDER?')
Flex.write(':SYSTem:BORDER LENDian')
data = Flex.query_binary_values(':WAVeform:XYFormat:FLOat:YDATa?',
	datatype='f',
	container=list,
	is_big_endian=False,
	header_fmt='ieee')
Flex.write(':SYSTem:BORDER ' + endianness)

Endianness of Returned Definite-Length Block Data

To correctly interpret definite-length block data, you must know the endianness (byte order) of the returned data (integers or real) from FlexDCA and you will must likely need specify this same endianness in your program language's command that is used to query the data. Endianness can be set to "little endian" order in which the least significant byte is sent first and the most significant byte sent last. Or, the endianness can be set to "big endian" order in which the most significant byte is sent first and the least significant byte sent last.

To specify or query the endianness setting for binary block data, use the :SYSTem:BORDer command. The endiannes setting applies to all binary queries except for :DISK:FILE:READ? query.

If you plan to change FlexDCA's current endian setting, it is a good practice to query FlexDCA's current endian setting and restore the setting when your program completes. This will avoid other programs having errors due to assuming a particular endianness setting.

After a factory preset (:SYSTem:FACTory), sets little endian. A default setup (:SYSTem:DEFault) does not affect endianness.