Can any cRIO modules provide open-collector outputs?

[ccherry]

I am trying to emulate the open-collector output of a fan tachometer, which outputs either Low or Hi-Z, with a cRIO module.  I haven't been able to find any, however, that will accomplish this; the best I could find was switching the IO direction on a 9401 between input and output, but four of the eight channels must be set to input/output at a time and the switching time between directions is unspecified.  Am I overlooking something?

[PahlM]

Hello ccherry,

You are correct that the 9401 I/O pins are configured by port, meaning all four pins on the port are the same direction. 

Have you been able to implement the method in this article in order to make an open-collector output?

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019N8KSAU&l=en-US

Cheers,

Michael Pal