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Route Sample Clock Through External PFI

Hello all,

 

I am trying to configure my PXI-6733 AO board to route an AO task sample clock to the PFI channel. I am doing this in Visual c#.

 

I want to be able to use this signal external to the PXI chassis. I have this so far (AOTask is an instance of the c# class representing an analog output task):

 

AOTask.ExportSignals.ExportHardwareSignal(ExportSignal.SampleClock, "PXI1Slot4/PFI5");

 

I have tried putting this before and after the AOTask.Timing.ConfigureSampleClock(....)

 

I verify the task and everything appears as it should, and I get no errors when trying to debug. So everything would have appeared to work, except nothing appears externally on PFI5, which is the PFI channel with a direct route to the AOSampleClock.

 

Do I have to specifiy somewhere else that PFI5 should be configured as an output - it just sits there at 5V for the duration of the output task.

 

This is driving me crazy, thanks in advance for any help.

 

Kyle

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Hi Kyle,

 

Could you give some information on how you reading the PFI5? The Sample clocks tend to run very fast and if you can not read it with a fast enough Sample rate it could appear as a constant value.

 

Kind regards,

 

Tom

Tom T
Applications Engineer
National Instruments UK&Ireland
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Hi Tom,

 

Yep, that was exactly it. I was wrongly expecting to see a 50% duty cycle on the sample clock. The sampling rate of the oscilloscope I was using was just too slow and missing the 'ticks'.

 

Everything was working after all.

 

Thank-you for your message.

 

Kyle

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