Convert* Signal; Figure 4-21. Startscan Output Signal Timing - National Instruments DAQ PCI E Series User Manual

Chapter 4 Signal Connections
STARTSCAN
Start Pulse
CONVERT*
STARTSCAN
PCI E Series User Manual
a. Start of Scan
t = 10 ns minimum
off
b. Scan in Progress, Two Conversions per Scan

Figure 4-21. STARTSCAN Output Signal Timing

The CONVERT* pulses are masked off until the board 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. The STARTSCAN
pulses should be separated by at least one scan period.
A counter on your PCI E Series board internally generates the
STARTSCAN signal unless you select some external source. This
counter is started by the TRIG1 signal and is stopped either by software
or by the sample counter.
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.

CONVERT* Signal

Any PFI pin can externally input the CONVERT* signal, which is
available as an output on the PFI2/CONVERT* pin.
t
w
t = 50-100 ns
w
4-34
t off
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