ADLINK Technology USB-1901, Руководство пользователя

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Operation 37
USB-1900 Series
4.2.1 Analog Input Circuitry
Figure 4-2: Analog Input
4.2.2 AI Data Format
The acquired 16-bit A/D data is 2’s complement coded data for-
mat. Valid input ranges and ideal transfer characteristics are
shown.
Table 4-1: Bipolar Analog Input Range and Output Digital Code
Description Bipolar Analog Input Range
Digital
code
Full-scale
range
±10 V ±2 V ±1 V ±0.2V
Least
significant
bit
305.2uV 61.03uV 30.51uV 6.1uV
FSR-1LSB 9.999695 V 1.999938 V 0.999969 V 0.199994 V 7FFF
Midscale
+1LSB
305.2 uV 61.03 uV 30.51 uV 6.1 uV 0001
Midscale 0 V 0 V 0 V 0 V 0000
Midscale
-1LSB
-305.2uV -61.03uV -30.51uV -6.1uV FFFF
-FSR -10 V -2 V -1 V -0.2V 8000
REF
VOLTAGE
4
0
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in
S
c
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w
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FO
FPGA
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Q
F
IF
O
P
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A
Analog
Input
MUX
DATA
16Bit ADC
250ks/s
C
o
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o
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AI[0..15]
AISENSE
In
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I C
h
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AI GND
Calibration
MUX