BinaryAcquisitionReadMe

used in the Measurement Studio, CVI, and console C examples.
The generic files call some externally defined C functions that are
specific for the development environment, such as the PlotWaveform
32 bit fetch = -2,147,484,468 to 2,147,484,467
For devices like the NI 5911 with up to 21 bits of resolution, you will need
to fetch 32-bit data. Fetching 8-bit data would be away resolution!
stored on onboard memory. Refer to the sample width example for more details
on this feature.
File Locations and Responsiblities:
Each NI-SCOPE example for CVI includes a directory of files specific to
displayed on the front panel of this example.
Another feature of this example is the while loop surrounding only Initiate
Acquisition and Fetch. This is the most efficient way to repeatedly acquire
The driver always fetches binary data from the digitizer using DMA.
Typically you will fetch scaled data, which is a double (8 byte) floating
point number in units of volts. However, it is faster to fetch the binary
data values constant for each fetch type, regardless of the device resolution,
as follows:
8 bit fetch = -128 to 127
16 bit fetch = -32,768 to 32,767
For devices like the NI 5620 and NI 5122 with 14 bits of reslution, there is
rarely a reason to fetch anything but 16-bit data.
For some devices it is possible to change the width of the data before it is
Finally, notice that the binary data size parameter changes which Fetch
function is used. The only difference is the size of the binary data
returned from the driver. For 8-bit devices such as the NI 5102 and NI
that example. In addition, each example project includes a generic .c
and .h file located in the cvi\samples\niScope\common directory. These
generic files include all the NI-SCOPE specific programming, and they are
5112, there is rarely a reason to fetch anything but 8-bit data. If you
fetch 16- or 32-bit data from these devices, the data is shifted left and
the least order 8 or 16 bits are always zero. This makes the min and max
function that displays the acquired waveform. In CVI, these functions
are located in the .c file for the example. This file implements the
GUI using CVI controls.
Example: Binary Acquisition
Recommended Input Signal: 100 kHz, 8 Vpp, sine wave
Devices Supported: Refer to NI Example Finder
CVI Description:
This example demonstrates fetching binary data instead of scaled data.
waveforms. However, the configuration of the digitizer, such as the
sampling rate and vertical range, cannot be changed while the example is
running.
data, which is a signed 8-, 16-, or 32- bit integer. Then you can scale
the data to voltage using the gain and offset scaling parameters returned
by the Fetch function in the wfmInfo structure. The scaling factors are