National Instruments PCI-6251 User Manual page 265

Appendix B Timing Diagrams
Quadrature and Two Pulse Encoder Timing
Counter n A, Counter n B, and Counter n Z, described in the
Counter n Z Signals
quadrature encoder or two-pulse encoder counting modes. Table B-35 shows the timing
requirements for these signals.
Figure B-51. Quadrature and Two Pulse Encoder Timing Diagrams
Counter n A
Counter n B
t
Counter n Z
Table B-35. Quadrature and Two Pulse Encoder Timing
Time
Counter n A Period
t
14
Counter n A Pulse Width
t
15
Counter n B Period
t
16
Counter n B Pulse Width
t
17
Counter n Z Pulse Width
t
18
Delay from Counter n A to Counter n B
t
19
Delay from Counter n B to Counter n A
t
20
*
The times in this table are measured at the pin of the M Series device. For example, t
minimum period of a signal driving a PFI, RTSI, or PXI_STAR pin when that signal is internally routed
to Counter n A.
B-40 | ni.com
section of Chapter 7, Counters, are used in position measurements using
t
14
t t
15 15
t
16
t
t
17
17
19
Description
t
18
Counter n A, Counter n B, and
t
20
t
18
*
Min (ns)
50.0
25.0
50.0
25.0
25.0
25.0
25.0
14
Max (ns)
—
—
—
—
—
—
—
specifies the