Operation Theory
29
AI Data Format
The data format of the acquired 16-bit A/D data is 2’s complement
coding. Table 4-1 shows the valid input ranges and the ideal
transfer characteristics.
Software Conversion with Polling Data Transfer
Acquisition Mode (Software Polling)
Considered the most convenient way to acquire a single A/D data,
the A/D converter starts one conversion whenever the dedicated
software command is executed. The software then polls the
conversion status and reads back the A/D data when it is
available.
Description
Bipolar Analog Input Range
Digital
code
Full-scale Range
±10V
±5V
±2.5V
±2V
Least significant bit
305.2uV
152.6uV
76.3uV
61.03uV
FSR-1LSB
9.999695V 4.999847V 2.499924V 1.999938V
7FFF
Mi1LSB
305.2uV
152.6uV
76.3uV
61.03uV
0001
Midscale 0V
0V
0V
0V
0000
Midscale -1LSB
-305.2uV
-152.6uV
-76.3uV
-61.03uV
FFFF
-FSR
-10V
-5V
-2.5V
-2V
8000
Table 4-1: Bipolar Analog Input Range and Output Digital Code
Description
Bipolar Analog Input Range
Digital
code
Full-scale Range
±1.25V
±1V
±0.5V
±0.25V
Least significant bit
38.14uV
30.51uV
15.25uV
7.62uV
FSR-1LSB
1.249961V 0.999969V 0.499984V 0.249992V
7FFF
Mi1LSB
38.14uV
30.51uV
15.25uV
7.62uV
0001
Midscale 0V
0V
0V
0V
0000
Midscale -1LSB
-38.14uV
-30.51uV
-15.25uV
-7.62uV
FFFF
-FSR
-1.25V
-1V
-0.5V
-0.25V
8000
Table 4-2: Bipolar Analog Input Range and Output Digital Code
Summary of Contents for NuDAQ PCI-9222
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Page 36: ...24 Hardware Information...