ADLINK USB-1210 - Manual (Page 33)

Operation & Calibration 23
USB-1210
Analog Input Circuitry
Figure 3-3: Analog Input
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 3-1: Bipolar Analog Input Range and Output Digital Code
Description Bipolar Analog Input Range Digital Code
Full-scale range ±10 V ±2 V N/A
Least significant bit 305.2 µV 61.03 µV N/A
FSR-1LSB 9.999695V 1.999938V 7FFF
Midscale +1LSB 305.2 µV 61.03 µV 0001
Midscale 0 V 0 V 0000
Midscale –1LSB -305.2 µV -61.03 µV FFFF
-FSR -10 V -2 V 8000
ADC
AI CHx_P
Signal Input
AI CHx_N
Signal Input
2nd order
LPF
With level shift
x1/2
PGA
PGA
With
x1 or x4
Si
g
nal Prote
c
tio
n
MUX
Path Selection
MUX
REF
IC
MUX
x1
Path_DC
Calibration SRC
x2
Cl
oc
k
SW
CLK
Buffer
2 MHz
A
D
C
O
N
V
_
C
H
0
ADCONV_CHn
Buffer