I am using the NI 9411 module paired with the cDAQ 9178 to read a frequency signal. I have successfully been able to read the frequency of a signal from a function generator by using the PFI 0 and PFI 1 channels on my cDAQ chassis. My question is if it is possible to use the Digital inputs on the NI 9411 to measure this frequency as well? My cDAQ chassis only has two PFI channels, so this will limit me to two frequency readings. I was wondering if there was a way to use the differential digital input the NI 9411 supports, or even the single ended inputs to read this frequency. Are these inputs strictly just for reading sensor voltages, and cannot be used with the cDAQS counters to determine the frequency of the signal?