routing 10MHz OCXO within the PXI-6608 not in slot 2

[cwierzynski]

Dear Forums,

I'd like to use the high-precision 10MHz OCXO oven-controlled oscillator on my 6608 to be the source of ticks for pulse generation tasks on the same card. Everything I read tells me to put the 6608 in slot 2 so that it drives the 10MHz backplane clock, then use PXI_Clk10_In as the source for my pulse generation tasks. But what if I don't want to have the 6608 in slot 2? Is there a way to route the OCXO 10MHz clock to the various inputs of the counters?

Using the legacy drivers (NI-DAQ) I was able to route the "stable 10MHz" signal to RTSI lines, and then specify that RTSI line as the source for a counter task. Is this approach possible using DAQmx ?

Many thanks,

Casimir 

[Scott-M]

Hi Casimir,

The 6608s OCXO clock is designed to be used from the timing slot so that all other devices can PLL to the most stable clock available, why can't you use the 6608 in slot 2?

Unfortunately, looking at the available routes it doesn't look like using the OCXO clock will be an option from another slot, specifically because "OCXO" or "stable 10MHz" are not options from the DAQmx connect terminals VI. 

Let us know if you have any further questions, or if we can help in anyway.

Thanks

Scott M.

[cwierzynski]

Hi Scott,

The problem is that I am using several PXI-4472 cards in the same chassis. I would like to sync these together using a multidevice task in DAQmx, which requires one of these cards to be in slot 2. 

At the same time, I'd like to route the sample clock from the master 4472 card to the 6608 so that it can be timestamped using the high-quality OCXO clock.

I used to be able to do this using the legacy NI-DAQ drivers -- I could route the 6608's OCXO to one of the RTSI lines, and use that as the source for a counter task. Is there a workaround using DAQmx? or are the 4472 and 6608 cards now mutually incompatible?

Thanks!

Cas

[Aditya.Jain]

I have a similar problem whereby I want to use a more precise 10 MHz signal. Instead of using an NI timing card, I am trying to over-ride the PXI chassis internal clock which has only 25ppm accuracy. I am supplying a 10 MHz signal externally using the BNC connector at the back of the PXI 1042 chassis which supposdly overwrites the backplane clock.

Is there any way to know that the PXI backplane has detected my new clock and the data acquistion is using this new reference clock?

[HeatherBaker]

Cas,

I am assuming you previously implemented the method described in this discussion forum.  Take a look at the attached snippet in conjunction to replace step 4 with this example VI.

Aditya.Jain,

As described in the PXI-1042 manual the clock should automatically override the 10 MHz clock provided by the backplane.  However, attached is a VI that I found using NI-Sync that might work to notify you.

[djac91]

Hello,

Were you able to route the 10MHz OCXO to backplane as mentioned using the Daqmx drivers?

I would like to know hoe it was done