1 analog input circuitry, 2 ai data format, Analog input circuitry – ADLINK USB-1903 User Manual
Page 51: Ai data format, Figure 4-2, Analog input, Figure 4-2: analog input
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
40-p
in
Sc
rew T
e
rm
inal
AI
4k
-Sa
m
ple
FIFO
FPGA
AI D
A
TA
SPI Control
A
rithmet
ic
Pr
oce
ss
CGQ
FIFO
PG
A
Analog
Input
MUX
DATA
16Bit ADC
250ks/s
Co
nne
ct
Typ
e
Sele
ct
io
n
AI[0..15]
AISENSE
In
pu
t G
ain
Se
le
ctio
n
Co
n
n
ec
tio
n
co
n
fig
u
ratio
n
AI
C
h
an
n
el
Se
le
ct
AI GND
Calibration
MUX