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Chapter 2 Function Reference — WFM_Load
NI-DAQ FRM for PC Compatibles 2-426
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National Instruments Corporation
buffer is an array of integer values that are converted to voltages by DACs. If your device has
12-bit DACs, the data ranges from 0 to 4,095 in unipolar mode and from –2,048 to 2,047 in
bipolar mode. If your device has 16-bit DACs, the data ranges from 0 to 65,535 in unipolar
mode and from –32,768 to +32,767 in bipolar mode.
Note For all devices except the DAQArb devices, data points for the output channels
need to be interleaved when you set up the buffer parameter.
The DSA devices have 18-bit DACs and operate only in bipolar mode. Data ranges from
–131,072 to +131,071. For DSA devices each buffer element is 32 bits wide. Each data point
goes in the upper 18 bits of its buffer element. You should set the lower 14 bits to zero.You
can move each data point into the upper 18 bits with a left shift operation or by multiplying it
by 16,384.
Note The following information applies to DAQArb 5411 devices only:
Refer to the mode parameter description to learn more about different modes and staging.
count is the number of points in your buffer. When you use interleaved waveform generation,
count should be a multiple of numChans and not less than 2 * numChans. When you use
double-buffered interleaved waveform generation, count should not be less than 4 *
numChans.
Range: 1 through 2
32
–1 (most devices).
2 through 2
24
(E Series and 4451devices).
On the PCI-61XX devices, the buffer must contain an even number of samples because of the
32-bit FIFO.
Table 2-39.
Data Ranges for the Buffer Parameter for DAQArb 5411 Devices
Mode Data Range Buffer
0 not supported Not supported
1, 2, 3 –32,768 to +32,767 Contains data values that are converted to
voltages by the DAC
4 –32,768 to +32,767 Contains stages for generating multiple
waveforms