difference between RTSI and PFI in synchronization

[dragondriver]

Hi all,

  I have a quick question about the difference between the RTSI and PFI pin used in synchronization. I have 6711 card and I am going to use external clock to drive the analog output and the counter output. Someone said I can use PFI as the source and I read the manual, it seems that I can use the 20MHz pin of RTSI as the timebased also. So if I connected a 10MHz clock to the RTSI timebased pin, does it mean all output is based on that clock? do I have to configure in the software to make it work? I it is confusing because RTSI has 8 pin pairs and the first one is timebase, there are some for analog output, some for analog input. I need to clocking the analog output and counter output. Should I change connect the external clock to the RTSI timebase or connect to the RTSI analog output and counter output ?

[MarisolM · Accepted solution]

Hello there;

The main difference is that triggers acquired or events generated from PFI lines are synchronous with the data, so they have a data/clock phase relationship. On the other hand, triggers acquired with RTSI lines are not synchronous with the data so there may be no such relationship.

So pretty much if you need triggers and events to be synch with the clock use the PFI lines

Here is a KB with more info

Hope it helps

Greetings

[John_P1]

That KB refers specifically to HSDIO devices (the 6711 isn't one of those).  The information in fact does not apply to the 6711, using PFI or RTSI should be acceptable for using an external clock/timebase on the 6711..

Refer to the AO Series User Manual (Figure 3-3 is a good visual representation of routing options specific to AO clock generation) for an overview of digital routing.

The counter's source input can be routed from any of the PFI or RTSI lines according to the routing table in MAX.

Best Regards,