PXI-6143 sample clock disciplining

[poklad]

Hi All!

I have PXI-6682+6653+4462+6143.

I use 6682+6653 for disciplining PXI_CLK10 for disciplining 4462 sample clock.

But, as I understand, the 6143 can not use PXI_CLK10 as reference clock source.

How can I discipline clock rate of the 6143, using 6682+6653?

Jury

[r_good]

Hello poklad. 

I encountered the same problem.  What you would have to do is route the PXICLK10 to one of the trig lines and route the trig line to the 6143.  I am going to follow up with an example if I can find it (I upgraded to X series devices on PXIe and no longer use my 6123 or 6143).

Chapter 10 section 2 of the s series user manual shows the routing you can achieve.  As you can see Trig 7 is available to route to and from the Master Timebase of the card.  You can use the 6682 disciplined clock and route to trig 7 and then to the 6143.  I did not keep this configuration very long so I never tested stability or jitter but I achieved very nice sync to my R series devices this way.

Let me know if this helps, I will try and see what I can find.

Adam

[poklad]

Hi!

Thank you for answer! The example will wery usefull.

Jury

[r_good]

Yea I will put something together.  I see you are syncing to some 4462's as well.  I also have a similar set up and still utilize the 4462.  

What method are you using to sync those?

You have to send a sync pulse, start trig, and diciplined clock to the 4462 for proper alignment.  I accomplish this all using my 6672 (in your case 6682, I will check and make sure it is compatible) and the use of global software triggers.

Just wanted to ask.  I will post something in the coming hour or so.

Adam

[r_good]

Okay so here is a quick VI with some comments.  I used examples from the community to piece this together over time so it is possible to find some similar examples somewhere on here.

As for the 6682, you cannot issue a global software trigger so most of this is not directly portable.  Some people on the forum have thought of ways around this so this VI should get you started for how to do some things (such as the main thing you requested which is disciplining the 6143 to PXI10) but to issue the triggers you will have to find something more clever.

I hope this helps.  I am home and away from my hardware so please note this exact VI has not been tested, simply a compilation of snippets from a much larger program.  (there is no useful front panel, and the BD is not the cleanest)

Best,

Adam

[poklad]

Hi!

I use "Multi-device PXI_Clk10 Disciplining 1.1" for long-time stability 10MHz clock. And I use PXI_CLK10 as time reference for 4462. I start acquisition by the generating future time event from the 6682, using PXI_Trig0.

Thank you for the sample vi. I see it some times later.

With best regards,

Jury

[poklad]

Hi!

I explore this vi and have some questons...

I create application for long-time monitoring measurements. In my hardware there are several ADC cards (now - 4462 and 6143, but in future, another cards will be added). Each card will start/stop independently. For the start aqcusition I use "future time event" from 6682, using PXI_Trig line. For long-time stability of the sample clock I planed to use PXI_CLK10, which driven from 6653 oscillator, which disciplined by the 6682.

As I understand, due to the 6143 can not use PXI_CLK10 directly, I must route PXI_CLK10 to PXI_Trig6 (for example) and in DAQmx timing (for 6143 task) set the RefClk.src to PXI_Trig6.

Is this correct?

Jury

[r_good]

Close.  The 6143 can only import the master timebase via Trig 7.  

About 3/4 through the example you will see a section that sets the property node of the 6682's sync clock source to the PXI10 which is already disciplined from earlier in the data flow.  After I set the sync source to PXI10, I then route the full speed clock (which is our disciplined clock) to PXI Trig 7.

When developing your acquisition for the 6143, you must set the Master TImebase to PXI trig 7 via the 6143 property nodes.  I do not think you need to do any manual routing other than that but I could be mistaken.

The 6653 allows you to utilize the global software triggers and therefore the full example I sent.  It is important with DSA devices to sync the ADC's using the sync pulse before a "future time event" triggers the acquitision (this is what I suspect I could be wrong).  I do something similar since my 6672 cannot sync to GPS but I have a 6682 that can.  When needed I route the GPS disciplined clock to the 6672 for further routing.  

Please make sure you are using PXI Trig 7 for the 6143 Master timebase routing or this will not work.  As for expanding, you will be in pretty good standing with your hardware since you can route triggers to trig and star lines, both software and hardware with the 6653 so syncing other cards should be no problem.  I have too many device families to count and they all follow this method, have not had issues yet.

Hope it helps.

Adam

[r_good]

Also the property you need to set for the 6143 is not te RefClkSrc but rather the MasterTimebase.Src, also I manually set the property MasterTimebase.Rate to 10M as well.