Hi all
I've got a problem synchronizing my onboard clock of a PXI-4461 with a SyncPulse sent by a PXI-6652 card.
I've got the following configuration of my PXI-1044 chassis
Slot 2: PXI-6652
Slot 4: PXI-4461
Slot 6: PXI-4461
Slto 8: PXI-6551
The 6652 generates a DDS clock of 22.05kHz which is sent via PXI_Star to the PXI-6551.
The PXI-4461 generate their own sample clock of 22.05kHz (they have to, because they use an oversample clock which can't be routed).
To phase lock them to the DDS clock, I've tried to send a SyncPusle to the 4461 card with the Global Software Trigger from NI-Sync. The trigger
is synchronized to the Full Speed Clock without any delay.
When I observe the clocks on an oscilloscope (I've routed the signals to the PFIs of the PXI-6652) I can see a delay of more than half a clock cycle.
Why is this so? I think I can disregard the propagation delay... Even if I send the Software Trigger on the falling edge I get a clock difference of 5us (10E-6).
I have attached a screen dump of the oscilloscope and a simplified VI which only does one AI-Task and the clock task.
Can anyone tell me how I can get the clocks synchron?
So far I've also tried to produce an oversample clock to send the SyncPusle with a delay related to that clock...
Is there anywhere a more precise description of the Global Software Trigger.
Any help will be appreciated
Cheers,
Christian
