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Chapter 3
Signal Connections
Counter Pairs
Note
The NI 6601 uses counters <0..3> only.
Counter Applications
Note
For more information about programming counter applications and triggers in
software, refer to the NI-DAQmx Help, and/or use the examples that are available with
NI-DAQmx.
Real-Time System Integration Bus
NI 660x User Manual
Each counter on the TIO is paired with another counter. This pairing allows
some counter signals to connect to signals on the other counter. The
counters are paired as ctr0 with ctr1, ctr2 with ctr 3, ctr 4 with ctr5, and ctr6
with ctr7.
Ctr0InternalOutput, which you can connect to Ctr1Gate, is an example of
two signals that you can connect between the ctr0/ctr1 pair. Conversely, to
connect Ctr0InternalOutput to Ctr2Gate, you must use other circuitry on
the TIO device (such as RTSI Triggers).
You can use the TIO device in the following counter-based applications:
•
Counting Edges
•
Frequency Measurement
•
Period Measurement
•
Position Measurement with Linear and Angular Encoders
•
Pulse Width Measurement
•
Semi-Period Measurement
•
Two-Edge Separation Measurement
•
Pulse Generation
You can perform these measurements through programmed I/O, interrupt,
or DMA data transfer mechanisms. The measurements can be finite or
continuous in duration. Some of the applications also use start triggers,
pause triggers, and hardware arm triggers.
TIO devices use the National Instruments Real-Time System Integration
(RTSI) bus to easily synchronize several measurement functions to a
common trigger or timing event. In a PCI system, the RTSI bus consists of
the RTSI bus interface and a ribbon cable. The bus can route timing and
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