Chapter4 ConnectingSignals
NI6013/6014 User Man ual 4-28 ni.com
Figure4-20. CONVERT*Output Signal Timing
The SI2 counter on the NI 6013/6014 normally generates CONVERT*
unless you select some external source. The counter is started by the
STARTSCANsignal and continues to count down and reload itself until
the scan isfinished. It then reloads itself in preparation for the next
STARTSCANpulse.
A/D conversionsgenerated by either an internal or external CONVERT*
signalare inhibitedunless they occur within a DAQsequence. Scans
occurring within a DAQsequence may be gated by either the hardware
(AIGATE)signal or software command register gate.
AIGATE Signal
Any PFIpin can ext ernally input the AIGATE signal, which is not
available asan output on the I/O connector. AIGATE can mask off scans
ina DAQ sequence. You can configure the PFI pin you select as the source
forAIG ATE inl evel-detection mode. You can configure the polarity
selection for the PFI pin for either active high or active low. In
level-detection mode if AIGATE is active, the STARTSCAN signal is
maskedoff and no scans can occur.
AIGATEcan n eithers top ascan in p rogress nor continue a previously
gated-offscan; in other words, once a scan has started, AIGATE does not
gateoff conversions until the beginning of the next scan and, conversely,
ifconversions are being gated off, AIGATE does not gate them back on
until the beginning of the next scan.
tw=50to150ns
tw