Figure 4-1. block diagram of ni pxi-4224, Figure 4-1, Block diagram of ni pxi-4224 -2 – National Instruments Isolated Analog Input Device NI PXI-4224 User Manual
Page 29
Chapter 4
Theory of Operation
4-2
ni.com
Figure 4-1. Block Diagram of NI PXI-4224
NI-PGA
Input
Protection
AI0
Input
Protection
AI1
Input
Protection
AI2
Input
Protection
AI3
Input
Protection
AI4
Input
Protection
AI5
Input
Protection
AI6
Input
Protection
AI7
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
PGA
Po
s
t
Filter
IS
O
Amp
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
Opto
Is
ol
a
tion
T
rigger
Interf
a
ce
An
a
log Input
Timing/Control
DMA/
Interr
upt
Reque
s
t
Bu
s
Interf
a
ce
DA
Q
-S
TC
Digit
a
l
I/O
RT
S
I Bu
s
Interf
a
ce
AI Control
IRQ
DMA
An
a
log
Input
Control
EEPR
O
M
Control
DMA
Interf
a
ce
Plug
a
nd
Pl
a
y
D
A
Q-APE
Bu
s
Interf
a
ce
82C55
DIO
Control
DA
Q
-S
TC
Bu
s
Interf
a
ce
EEPR
OM
RT
S
I
PXI Connector
Control
Addre
ss
/D
a
ta
Gener
ic
Bu
s
Interf
a
ce
PCI
Bu
s
Interf
a
ce
MINI-
MITE
EEPR
OM
S
MB
S
ign
a
l Cond
Ref
erence
s
Configur
a
tion
Memor
y
An
a
log
Input
MUX
C
a
l
MUX
An
a
log
Mode
Multiple
xor
A/D
Con
v
e
rter
ADC
FIFO
C
a
libr
a
tion D
A
C
s
V
olt
a
ge
Ref
D
a
ta
T
emp
S
en
s
or