Справочник Пользователя для National Instruments NI PCI-6111
Chapter 4
Connecting Signals
© National Instruments Corporation
4-23
Figure 4-16. 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 SI2 reaches zero. If you select an
external CONVERT*, the first external pulse after STARTSCAN generates
a conversion. The STARTSCAN pulses should be separated by at least one
scan period.
STARTSCAN signal. If you are using internally generated conversions,
the first CONVERT* appears when SI2 reaches zero. If you select an
external CONVERT*, the first external pulse after STARTSCAN generates
a conversion. The STARTSCAN pulses should be separated by at least one
scan period.
A counter on the NI PCI-6110/6111 device internally generates
STARTSCAN unless you select some external source. This counter is
started by the TRIG1 signal and is stopped by either software or the SC.
STARTSCAN unless you select some external source. This counter is
started by the TRIG1 signal and is stopped by either software or the SC.
Scans generated by either an internal or external STARTSCAN signal are
inhibited unless they occur within a DAQ sequence. Scans occurring within
a DAQ sequence may be gated by either the hardware (AIGATE) signal or
software command register gate.
inhibited unless they occur within a DAQ sequence. Scans occurring within
a DAQ sequence may be gated by either the hardware (AIGATE) signal or
software command register gate.
The NI PCI-6110/6111 uses a three-point analog FIFO to digitize the input.
Although the point is digitized on the appropriate edge of STARTSCAN
(internally supplied unless you pass 0 for the scanTimebase), it is not sent
to NI-DAQ until three additional edges of STARTSCAN clock the point.
Consequently, you may not see the last three points of the acquisition.
Although the point is digitized on the appropriate edge of STARTSCAN
(internally supplied unless you pass 0 for the scanTimebase), it is not sent
to NI-DAQ until three additional edges of STARTSCAN clock the point.
Consequently, you may not see the last three points of the acquisition.
b. Scan in Progress, Two Conversions per Scan
Start Pulse
CONVERT*
STARTSCAN
t
off
= 10 ns minimum
t
off
t
w
= 25 to 50 ns
t
w
a. Star of Scan