National Instruments NI 6711 User Manual

Also see for DAQCard-6715: User manual User manual

Contents

National Instruments NI 6711 User Manual Manual pdf 51 page image

Chapter 4 Digital I/OAnalog Output Series User Manual 4-4 ni.comDI Sample Clock Signal (NI 6731/6733 Only)Use the DI Sample Clock (di/SampleClock) signal to sample the P0.<0..7>terminals and store the result in the DI waveform acquisition FIFO.Because there is no dedicated internal clock for timed digital operations,you can use an external signal or one of several internal signals as theDI Sample Clock. You can correlate digital and analog samples in time bychoosing the same signal as the source of the DI Sample Clock, AI SampleClock, or DO Sample Clock.If the DAQ device receives a di/SampleClock when the FIFO is full, theDAQ device reports an overflow error to the host software.Using an Internal SourceTo use di/SampleClock with an internal source, specify the signal sourceand the polarity of the signal. The source can be any of the followingsignals:• AO Sample Clock• Counter 0 OutProgram the DAQ device to sample the DIO terminals on the rising edge orfalling edge of di/SampleClock.Using an External SourceYou can use a signal connected to any RTSI <0..6> pin as the source ofdi/SampleClock. You can sample data on the rising or falling edge ofdi/SampleClock.Any PFI line that can be routed to RTSI can also be used as the clocksource. Refer to Device Routing in MAX in the NI-DAQmx Help or theLabVIEW Help in version 8.0 for more information.You must ensure that the time between two active edges of thedi/SampleClock is not too short. If the time is too short, the DI waveformgeneration FIFO is not able to store the sample fast enough.