external clocking on 6711 card

[PKIM]

Hi all,

  I just read the manual of the card PCI6711, it supports the external clock. So does it mean we can change the update rate by using different external clock rate?

[chris88]

Hi PKIM

Yes you can change the sample clock rate using an external source. This will change the update rate of the outputs of the card.

However keep in mind that the maximum frequency you can set as an external output is 20MHz. This signal needs to be connected to any PFI or RTSI pins. 

Regards

[dragondriver]

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@chris88 wrote:

Hi PKIM

Yes you can change the sample clock rate using an external source. This will change the update rate of the outputs of the card.

However keep in mind that the maximum frequency you can set as an external output is 20MHz. This signal needs to be connected to any PFI or RTSI pins. 

Regards

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Oh, I have the same question about the external clocking. It is said that 6711/6713 only support software-based clocking so the manual said we can connect external clock to PFI or RTSI as timing.

So which one is corrected? What's different to go on PFI or RTSI as source? Which PFI should I go for? And in the code, should I just choose PFI as the source of sampling clock?

[chris88]

HI dragondriver

They are both correct, the PCI 6711 supports external clocking for the analog output tasks, but for Digital I/O tasks the timing can only be set to software timed, meaning that you cannot use external clock for digital tasks.

The main difference between RTSI and PFI is the physical connection, PFI lines conects through the connector block you are using and the RTSI is connected through a RTSI bus cable used to synchronize several DAQ cards.

You can choose any PFI <0 to 9> and this article show how to select which PFI line is the source of sampling.

Regards

[dragondriver]

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@chris88 wrote:

HI dragondriver

They are both correct, the PCI 6711 supports external clocking for the analog output tasks, but for Digital I/O tasks the timing can only be set to software timed, meaning that you cannot use external clock for digital tasks.

The main difference between RTSI and PFI is the physical connection, PFI lines conects through the connector block you are using and the RTSI is connected through a RTSI bus cable used to synchronize several DAQ cards.

You can choose any PFI <0 to 9> and this article show how to select which PFI line is the source of sampling.

Regards

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Thanks for the clarification . I only one doubt. Someone told me that 6711 only supports software-based digital pulse input/output but it supports external-clock-driving counter output. So when you said softwarebased digital I/O task, do you mean all digitals output including counter output? Thanks.

[Dennis_Knutson]

Digital I/O is separate from counter/timer operations.