For M Series and cDAQ cards, NI-DAQ™mx currently supports digital line filtering on counter input tasks only, not DIO tasks. You can enable a programmable debouncing filter on each PFI, RTSI, or PXI_STAR signal. Enabling debounce filters when the PFI line is not a part of a counter task (e.g. AI Sample Clock or Digital Trigger) requires the use of a dummy counter as shown below.
This workaround sets up and commits a "dummy" counter task using the PFI line of interest as one of the counter inputs and enabling filtering on it through the counter options of the DAQmx Channel Property Node. Please see the below snippet for an example of using this workaround for the filtering of a digital start trigger.
For M Series devices the valid values for the minimum digital pulse width are 0s, 2.56ms, 6.425us and 125ns. Also, we can apply this workaround to both RTSI and the PXI Star filters.