© National Instruments | 5-1
5
Counters
The cDAQ chassis has four general-purpose 32-bit counter/timers and one frequency generator.
The general-purpose counter/timers can be used for many measurement and pulse generation
applications. Figure 5-1 shows the cDAQ chassis Counter 0 and the frequency generator. All
four counters on the cDAQ chassis are identical.
Figure 5-1. Counter 0 and Frequency Generator
Counters have eight input signals, although in most applications only a few inputs are used.
For information about connecting counter signals, refer to the Default Counter/Timer Routing
section.
Each counter has a FIFO that can be used for buffered acquisition and generation. Each counter
also contains an embedded counter (Embedded Ctrn) for use in what are traditionally
two-counter measurements and generations. The embedded counters cannot be programmed
independent of the main counter; signals from the embedded counters are not routable.
Counter Timing Engine
Unlike analog input, analog output, digital input, and digital output, the cDAQ chassis counters
do not have the ability to divide down a timebase to produce an internal counter sample clock.
Counter 0
Counter 0 Source (Counter 0 Timebase)
Counter 0 Aux
Counter 0 HW Arm
Counter 0 A
Counter 0 B (Counter 0 Up_Down)
Counter 0 Z
Counter 0 Gate
Counter 0 Internal Output
Counter 0 TC
Input Selection Muxes
Frequency Generator
Frequency Output Timebase Freq Out
Input Selection Muxes
Embedded Ctr0
FIFO
Counter 0 Sample Clock
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