Sync 2 cDAQ Sync Distance

[GregAA]

Hello,

I am planning to share the sample clock on two cDAQ-9188 chassis by using the PFI connections from the chassis itself (BNC connectors with a coax cable).

What is the practical distance I can expect to be able to separate these cDAQ devices using this method? I am sampling at relatively low speeds (10kHz worst case). I would assume signal degradation would become an issue before the effects of the delay due to propagation of the signal through the coax cable.

Is it reasonable to expect to be able to have 100ft of coax between the devices? Propagation delays would be in order of nanoseconds for this distance, which would be totally negligible for this application.  Does anyone have any experience that would indicate what distance will cause this approach to fail?

[Ryan_K.]

The specifications sheet seems to indicate that the maximum cable length that can be used on a PFI connection is 10ft.

It's not impossible that a longer cable would work, but there are a number of different variables (cable type, environment, etc.) that could affect the system's performance. It might be worth simply testing your proposed system out and seeing how it performs (if that's feasible). However, it does look like the 9188 is not rated for a connection of greater than 10 ft.

Hope the spec sheet helps, and sorry if it wasn't the answer you were looking for.

Regards,

[NEWKlear]

Hey GregAA,

You may be interested in the 9469 modules that allow for synchronization over longer distances for the cDAQ platform. 

https://www.ni.com/en-us/shop/model/ni-9469.html