National Instruments 321645c-01 用户手册
Chapter 2
Function Reference — GPCTR_Set_Application
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National Instruments Corporation
2-241
NI-DAQ FRM for PC Compatibles
Figure 2-29. Buffered Pulse Width Measurement
Note
You must make sure that there is at least one source transition during the
measured pulse and between consecutive measured pulses in order for this
application to work properly.
measured pulse and between consecutive measured pulses in order for this
application to work properly.
Caution
If the gate signal is high (when
ND_GATE_POLARITY
is
ND_POSITIVE
) during
arriving of the counter, counting starts immediately, and the first count is saved on
the first high-to-low transition. The same applies to low gate signal during arming
of the counter when
the first high-to-low transition. The same applies to low gate signal during arming
of the counter when
ND_GATE_POLARITY
is set to
ND_POSITIVE
; in this case, the
first count gets saved on the first low-to-high transition.
Figure 2-30. Buffered Pulse Width when Gate Is High during Arming
Source
Buffer
Gate
Measured
Pulse Width
Measured
Pulse Width
Measured
Pulse Width
1
2
3
1
2
3
1
2
3
4
5
3
3
5
3
3
3
!
Source
Buffer
Gate
Measured
Pulse Width
Measured
Pulse Width
Measured
Pulse Width
1
2
3
1
2
3
1
2
3
4
5
3
3
5
3
3
3