© National Instruments | 7-35M Series User ManualEnabling Duplicate Count Prevention in NI-DAQmxYou can enable duplicate count prevention in NI-DAQmx by setting the Enable DuplicateCount Prevention attribute/property. For specific information about finding the EnableDuplicate Count Prevention attribute/property, refer to the help file for the API you are using.Synchronization ModesThe 32-bit counter counts up or down synchronously with the Source signal. The Gate signal andother counter inputs are asynchronous to the Source signal. So M Series devices synchronizethese signals before presenting them to the internal counter.M Series devices use one of three synchronization methods:• 80 MHz Source Mode• Other Internal Source Mode• External Source ModeIn DAQmx, the device uses 80 MHz source mode if you perform the following:• Perform a position measurement• Select duplicate count preventionOtherwise, the mode depends on the signal that drives Counter n Source. Table 7-8 describes theconditions for each mode.Table 7-8. Synchronization Mode ConditionsDuplicate CountPrevention EnabledType ofMeasurementSignal DrivingCounter n SourceSynchronizationModeYes Any Any 80 MHz SourceNo PositionMeasurementAny 80 MHz SourceNo Any 80 MHz Timebase 80 MHz SourceNo All Except PositionMeasurement20 MHz Timebase,100 kHz Timebase,or PXI_CLK10Other InternalSourceNo All Except PositionMeasurementAny Other Signal(such as PFI orRTSI)External SourceArtisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
