DAQ assistant - External clock

[adishein]

I'm using PCI-6111 to sample a 2MHz signal. I'd like to sychronize the DAQ with the function generator via the 10MHz reference clock from the function generator. I set the sampling rate to 5M, connected the function generator 10MHz ref output to PFI0 and set the "advanced timing" to "external" and "PFI0". However I get a DAQ assistant error 200284 saying that the samples haven't been acquired (even when the timeout is very long). 

Is it possible to achieve the sychronization I want? 

Thanks, 

Adi

[Tirmizi]

here is a link may be it relate your problem

http://digital.ni.com/public.nsf/allkb/E5A08F0B939547238625686C008011F9

[adishein]

Thanks, but if this device does not support an exernal clock as the link says, what does the following sentence in its manual means: 

"Any PFI can externally input the AI Sample **bleep** Timebase signal which is (...) divided down to provide the Onboard Clock source for the AI Sample Clock... The maximum allowed frequency is 20MHz" ?

Thanks, Adi.

[adishein]

Should it be possible to sychronize to external clock using RTSI, by connecting a PFI pin to the RTSI clock, as described in the following link: http://digital.ni.com/public.nsf/allkb/5601C8268D625A3C86256CF50071199D ?

[John_P1]

There are some questionable KnowledgeBase articles out there...

The first one linked is using outdated terminology from NI's legacy DAQ driver (which I guess somebody might still find helpful...).  

The second one fails to mention that the aiSampleClockTimebase could just be routed through a PFI line rather than having to go through RTSI (EDIT:  The STC1's "Master Timebase" can only be overridden via RTSI7 but you shouldn't have to use this).

You can't specify the sample clock timebase using the DAQ Assistant though.  When you use the 10 MHz signal on PFI 0 as the external clock through the DAQ Assistant, the hardware will actually try to use this as the sample clock (i.e. sampling off of the 10 MHz signal directly rather than dividing it down to get 5 MHz) which it is too fast for its ADC.

So you'll have to use the lower level DAQmx API.  The sample clock timebase source and rate are configured via the following DAQmx Timing properties:

Best Regards,