National Instruments cDAQ-9172 User Manual download pdf (Page 42)

NI cDAQ-9172 User Guide and Specifications 42 ni.com

Counter Input Applications

Counting Edges

In edge counting applications, the counter counts edges on its Source after

the counter is armed. You can configure the counter to count rising or

falling edges on its Source input. You also can control the direction of

counting (up or down).

The counter values can be read on demand or with a sample clock.

Single-Point (On-Demand) Edge Counting

With single-point (on-demand) edge counting, the counter counts the

number of edges on the Source input after the counter is armed. On-demand

refers to the fact that software can read the counter contents at any time

without disturbing the counting process. Figure 16 shows an example of

single-point edge counting.

Figure 16. Single-Point (On-Demand) Edge Counting

You also can use a pause trigger to pause (or gate) the counter. When the

pause trigger is active, the counter ignores edges on its Source input. When

the pause trigger is inactive, the counter counts edges normally.

Counter Armed

SOURCE

Counter Value 1 0 5 4 3 2

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 83 84

No comments

National Instruments cDAQ-9172 User Manual Page 42