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Chapter 2
Using Your NI 653X
To prevent a transient data value during line switching from falsely causing a match,
Tip
set a valid pattern for at least 60 ns to guarantee detection. In addition, keep glitches to less
than 20 ns to guarantee rejection.
Choosing Continuous or Finite Data Transfer
NI 653X User Manual
Value to Detect
Pattern
Mask
Polarity
Figure 2-19. Pattern-Detection Trigger Example
You can continuously acquire data into or transfer data from computer
memory or specify the number of points you want to transfer.
Finite Transfers
For finite transfers, the NI 653X acquires the specified amount of data to a
computer memory buffer and stops the operation.
Continuous Input
For continuous input, the NI 653X continuously transfers input data to the
computer memory buffer. As the device fills the buffer, call the
function or the DIO Read VI to retrieve the data. If at
DIG_DB_Transfer
any time the device runs out of space in the buffer, it stops the operation
and NI-DAQ returns an error.
You can allow the device to continue when it runs out of buffer space and
overwrite data you have not yet read. You can specify this though the
parameter in the
oldDataStop
overwrite/regen. parameter in the Digital Buffer Control VI, called by the
DIO Start VI.
X
X
X
X
0
0
0
0
0
0
0
0
Postive: Search for Match
DIG_DB_Config
2-32
X
X
1
0
0
0
1
0
0
0
1
1
function and the data
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