Chapter 2
DAQ System Overview
2-2
ni.com
Figure 2-2.
USB-621
x
Block Diagram
DAQ-STC2
The DAQ-STC2 implements a high-performance digital engine for
M Series data acq
u
isition hardware. Some key feat
u
res of this engine
incl
u
de the following:
•
Flexible AI and AO sample and convert timing
•
Many triggering modes
•
Independent AI, AO, and CTR FIFOs
•
Generation and ro
u
ting of internal and external timing signals
•
Two flexible 32-bit co
u
nter/timer mod
u
les with hardware gating
•
Static DI, DO, and DIO signals
•
USB Hi-Speed 2.0 interface
•
Up to fo
u
r USB Signal Streams for acq
u
isition and generation
f
u
nctions
Calibration Circuitry
The USB-621
x
analog inp
u
ts and o
u
tp
u
ts have calibration circ
u
itry to
correct gain and offset errors. Yo
u
can calibrate the device to minimize
AI and AO errors ca
u
sed by time and temperat
u
re drift at r
u
n time.
No external circ
u
itry is necessary; an internal reference ens
u
res high
acc
u
racy and stability over time and temperat
u
re changes.
An
a
log O
u
tp
u
t
Digit
a
l I/O
An
a
log Inp
u
t
Co
u
nter
s
PFI
Digit
a
l
Ro
u
ting
a
nd Clock
Gener
a
tion
B
us
Interf
a
ce
B
us
I/O Connector
Digit
a
l
I
s
ol
a
tor
s
I
s
ol
a
tion
B
a
rrier
(U
S
B-6215/
6216/6218
device
s
only)
