Issue 31 in pylibnidaqmx: Aded support for read properties: read_relative_to, read_overwrite, offset,

[pylibn...@googlecode.com]

Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 31 by reddoghud: Aded support for read properties:
read_relative_to, read_overwrite, offset,
http://code.google.com/p/pylibnidaqmx/issues/detail?id=31

Hi there,

I've created a patch to implement the following ni-DAQmx read property
calls:

DAQmxGetReadRelativeTo() --> task.get_read_relative_to()
DAQmxSetReadRelativeTo() --> task.set_read_relative_to()
DAQmxResetReadRelativeTo() --> task.reset_read_relative_to()

DAQmxGetReadOverwrite() --> task.get_read_overwrite()
DAQmxSetReadOverwrite() --> task.set_read_overwrite()
DAQmxResetReadOverwrite() --> task.reset_read_overwrite()

DAQmxGetReadOffset() --> task.get_read_offset()
DAQmxSetReadOffset() --> task.set_read_offset()
DAQmxResetReadOffset() --> task.reset_read_offset()

These are useful when making measurements where only the last last x
samples in the buffer are required. Setting these properties and the clock
to continuous acquisition can also decrease the time required to start and
stop the task if you make frequent, repeated measurements. An example of
usage is below:

>>> from nidaqmx import AnalogInputTask
>>> task = AnalogInputTask()
>>> task.create_voltage_channel('Dev1/ai0', terminal='diff', min_val=0.,
>>> max_val=5.)
>>> task.configure_timing_sample_clock(rate=2e6, sample_mode='continuous',
>>> samples_per_channel=32000)
>>> task.set_read_relative_to('most_recent')
>>> task.set_read_overwrite('overwrite')
>>> task.set_read_offset(32000)
>>> task.start()
>>> task.read(32000)
array([[ 2.99478992],
[ 2.9951122 ],
[ 2.99478992],
...,
[ 2.99462878],
[ 2.9951122 ],
[ 2.99462878]])
>>> task.read(32000)
array([[ 2.99462878],
[ 2.99446764],
[ 2.99462878],
...,
[ 2.99478992],
[ 2.99495106],
[ 2.9951122 ]])

etc.

Tested with nidaqmx v. 9.5 and a USB-6363 DAQ box. The docstrings might be
a little verbose, so feel free to cut them down if you think it's
appropriate (I based them off of the C API documentation).

Thanks,
toki

Attachments:
libnidaqmx.py.patch 8.0 KB

[pylibn...@googlecode.com]

Updates:
Status: Done

Comment #1 on issue 31 by pearu.peterson: Aded support for read properties:

read_relative_to, read_overwrite, offset,
http://code.google.com/p/pylibnidaqmx/issues/detail?id=31

Applied to svn repo.

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