Chapter 2
Device Overview
2-8
ni.com
Transfer Rates
The maxim
u
m s
u
stainable transfer rate a TIO device can achieve for a
b
u
ffered acq
u
isition depends on the following factors:
•
Amo
u
nt of available b
u
s bandwidth
•
Processor speed and operating system
•
Application software
To red
u
ce the amo
u
nt of b
u
s activity, limit the n
u
mber of devices
generating b
u
s cycles. Beca
u
se direct-memory access (DMA) transfers are
faster than interr
u
pt-driven transfers, NI-DAQmx
u
ses DMA by defa
u
lt for
b
u
ffered acq
u
isitions.
Note
The maxim
u
m s
u
stainable transfer rate is always lower than the peak transfer rate.
Table 2-1 lists the maxim
u
m transfer rates for TIO devices.
Table 2-1.
Maximum Transfer Rates
DMA
Interrupt
.Finite Operation
Buffer Size (Samples)
Rate (kS/s)
Buffer Size (Samples)
Rate (kS/s)
100
5,000
100
77
1,000
2,150
1,000
77
10,000
1,600
10,000
77
100,000
1,350
100,000
77
Continuous Operation
Buffer Size (Samples)
Rate (kS/s)
Buffer Size (Samples)
Rate (kS/s)
100
44
100
7
1,000
202
1,000
46
10,000
212
10,000
75
100,000
245
100,000
76
defa
u
lt
212
defa
u
lt
75
