ON to OFF and OFF to ON Specification of Digital Modules

Updated Jun 5, 2018

Reported In


  • C Series Digital Module
  • NI-9422

Issue Details

I see that the C Series Digital Modules have different ways to specify the timing of the Module I/O. What does the Input Delay Time specification found in some datasheets means?


The input delay specification explains the behavior the module will have when detecting signals, meaning that there is going to be a delay in between when the signal arrives and when the module actually detects the change. 

That delay for an input going LOW to HIGH will have a maximum and a typical specification as well for the input going HIGH to LOW. These are important to take into consideration when choosing a module since the signal must maintain at that level for the specified amount in order to accurately measure the digital logic level.

Additional Information

You can go to http://www.ni.com/en-us/shop/select/c-series-digital-module and filter by Maximum Update Rate in order to decide which module is best for you.


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