National Instruments PCI-6281, Руководство пользователя

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B-40
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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 A, Counter n B, and
Counter n Z Signals
section of Chapter 7,
Counters
, are used in position measurements using
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
Table B-35. Quadrature and Two Pulse Encoder Timing
Time Description Min (ns)
*
Max (ns)
t
14
Counter
n
A Period 50.0 —
t
15
Counter
n
A Pulse Width 25.0 —
t
16
Counter
n
B Period 50.0 —
t
17
Counter
n
B Pulse Width 25.0 —
t
18
Counter
n
Z Pulse Width 25.0 —
t
19
Delay from Counter
n
A to Counter
n
B 25.0 —
t
20
Delay from Counter
n
B to Counter
n
A 25.0 —
*
The times in this table are measured at the pin of the M Series device. For example, t
14
specifies the
minimum period of a signal driving a PFI, RTSI, or PXI_STAR pin when that signal is internally routed
to Counter
n
A.
Co u nter n A
t
15
Co u nter n Z
t
15
t
14
Co u nter n B
t
17
t
17
t
16
t
19
t
1 8
t
20
t
1 8