National Instruments 6024E 用户手册
Chapter 4
Signal Connections
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4-37
deasserted t
off
after the last conversion in the scan is initiated. This output is
set to high impedance at startup.
Figure 4-25. STARTSCAN Input Signal Timing
Figure 4-26. STARTSCAN Output Signal Timing
The CONVERT* pulses are masked off until the device generates the
STARTSCAN signal. If you are using internally generated conversions, the
first CONVERT* appears when the onboard sample interval counter
reaches zero. If you select an external CONVERT*, the first external pulse
after STARTSCAN generates a conversion. Separate the STARTSCAN
pulses by at least one scan period.
STARTSCAN signal. If you are using internally generated conversions, the
first CONVERT* appears when the onboard sample interval counter
reaches zero. If you select an external CONVERT*, the first external pulse
after STARTSCAN generates a conversion. Separate the STARTSCAN
pulses by at least one scan period.
Rising-Edge
Polarity
Falling-Edge
Polarity
t
w
t
w
= 10 ns minimum
t
w
= 50-100 ns
a. Start of Scan
toff
t
off
= 10 ns minimum
Start Pulse
CONVERT*
STARTSCAN
STARTSCAN
b. Scan in Progress, Two Conversions per Scan
t
w