Chapter 2
Using Your NI 653X
©
National Instruments Corporation
2-13
Note
You should always read the least significant bits of the transfer count before reading
the most significant bits. The 32 most significant bits of the transfer count is cached in
software when you read the least significant bits.
•
LabVIEW—Use the Digital Buffer Write VI or the Digital Buffer
Read VI, which are called by the DIO Read VI, the DIO Write VI, and
the DIO Wait VI.
Connecting Signals
Connect digital input signals to the I/O connector using the pinout
diagrams, Figure C-1,
NI 653X I/O Connector 68-Pin Assignments
68-to-50-Pin Adapter Pin Assignments
If you are using an external source for your REQ signal, connect it to the
appropriate REQ pin of the I/O connector.
If you are using external start and/or stop triggers, connect to the
appropriate pins—start trigger (ACK/STARTTRIG) and/or stop trigger
(STOPTRIG).
Transfer
Direction
Attribute
Value Returned
Input
ND_READ_MARK_H_SNAPSHOT_GR1
Most significant 32 bits of transfer count
ND_READ_MARK_H_SNAPSHOT_GR2
ND_READ_MARK_L_SNAPSHOT_GR1
Least significant 32 bits of transfer count
ND_READ_MARK_L_SNAPSHOT_GR2
Output
ND_WRITE_MARK_H_SNAPSHOT_GR1
Most significant 32 bits of transfer count
ND_WRITE_MARK_H_SNAPSHOT_GR2
ND_WRITE_MARK_L_SNAPSHOT_GR1
Least significant 32 bits of transfer count
ND_WRITE_MARK_L_SNAPSHOT_GR2
Содержание NI 653 Series
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