how to export via pxi star trigger to multiple dvices

[golubovski]

Brooks,

Being concerned with how the 6713 could sense the ClkTimebase from the ST I forgot to mention that I had noticed the "PXI_Star" string redundancy and removed it from a working VI but not from the one I had posted. Yet, your last VI (DAQ AO Sync.vi) still produces the error -89125 at "DAQmx Write.vi" allthough all 8 triggers are available and route properly "Away from slot 1".

Attached is my technical MAX report and you are wellcome to use my email address if you find it faster and more appropriate. If it is possible, can you please eplain how the 6713 can use the Sample Clock Timebase from a 4472 - does the NI-DAQmx perform down division implicitely...?

Thank you for being supportive.

Sincerely,

[Brooks_C]

Hello Golubovski,

I believe that this will be resolved if you change the Trigger Line Routing from "Away from slot 1" to "Dynamic" for all 8 lines.  In my system all my lines are configured this way and when I change them to "Away from slot 1" I receive error -89125 as well.

I am currently looking into the documentation on this issue to see if I was either looking in the wrong place for an explanation or if our current knowledgebase should be edited to include information on this case.  Please let me know if this works for you, and I will post back when I have more information on the PXI_Star trigger lines.

At the lowest level it makes sense that you  wouldn't have to explicitly route lines away from slot 1 when using PXI_Star.  The PXI_Star lines route from slot 2 to each of the 13 slots to its right so the only option is to route away from slot 2 to the other segments.

Cheers,

[golubovski]

Brooks,

I will test that and maybe it would speedup the communication if we use email. However, the ST is used only for the ADC synchronization, the triggers are on the backplane and are needed to broadcast the Start Trigger for the DAQ operations. If this is true, how can that start trigger puilse be propagated to the 2nd and 3rd segment of the PXI if routing is "dynamic" thus the segments won't "see" each other?

Attached is a version that DAQs for 40 seconds based on the Traditional NI-DAQ. DSA master is sending ADC clock vis the ST bus, however, the AI Start Trigger is broadcasted via RTSI0 (PXI-Trigger 0) to the rest slaves(8x DSA & 1x MIO) and a divided trigger is send via RTSI1 (PXI_Trigger 1) to the counter of the MIO do make the AO firing synchronization with the AI sampling.

I am very confused now. I have tried to modify this VI to sample indefinite and stream to disk, but with longer AO buffers they start to mix after 20 seconds or so and nobody from the support could explain why, This is when I decided to move to NI-DAQmx but no this?

Can you find a 6713 to test its ability to sense the ADC clock from the ST bus?

I deeply apologize for the inconveniance but I don't know what to do next.

Sincerely,

[Brooks_C]

Hello Golubovski,

When you use analog input channel expansion with PXI-DSA cards like the PXI-4472 the signal routing is handled for you automatically so it is routing these signals for you behind the scenes.

I can probably track down a PXI-6713, but for the purpose of this test the PXI-6723 I used in my test should be identical.  I will post back after I've done this test.

Were you able to get your setup working by reconfiguring the trigger routing to be dynamic?

Cheers,

[golubovski]

Brooks,

I did try it but with error, however I also did post regarding that but the post is gone?!? Anyway, I just manged to connect to the console via RDP, change all 8 triggers to route "Dynamic" and start the VI. The error now is -89121!

---------------------------------------------------------------------------------------

Possible reason(s):

Destination terminal to be routed could not be found on the device.

Make sure the terminal name is valid for the specified device. Refer to Measurement & Automation Explorer or your hardware documentation for valid terminal names.

Property: SampClkTimebase.OutputTerm
Destination Device: PXI1Slot2
Destination Terminal: PXI_Star8PXI_Star8

Task Name: _unnamedTask<2>

-------------------------------------------------------------------------------------------------------------

It seems that 6713 cannot receive from the ST bus?!

Are you saying that [AI Start Trigger] is implicitely (automatically) perofromed for the members of the AI task (all 9x PXI-4472)?

What about the PXI-6713, is it also triggered to start its AO synchronized with the [AI Start Trigger]?

Look forward to hearing from you.

Sincerely,

[Brooks_C]

Hello Golubovski,

I think this looks like the same error you corrected earlier with the string.  The error says that you're trying to route to "/PXI1Slot2/PXI_Star8PXI_Star8" and that should be "/PXI1Slot2/PXI_Star8"  I'm guessing you just reverted to an older version of the VI?

If that doesn't answer your question can you please post your current version of your VI with the current values set as default (Edit» Make Current Values Default).

Cheers,

[golubovski]

Brooks,

Attached is the final version that works exactly as you say. Can you please test it and confirm? Now can you please explain the following that bothers me:

1. Are all 10 PXI cards synchronized with clock and start of operation (AI Start Trigger)?

2. If above is yes, how does 6713 understand the ADC clock from the DSA via ST bus?

3. How is the synchronization performed  when the 3 PXI segments do not see each other with the routing "Dynamic"?

 Sorry for the inconveniance and thank you in advance!

Sincerely,

[RT4CY]

Hello again golubovski!

Yes, all PXI devices are using the SampleClockTimeBase of the PXI-4472 in slot 2.  This is being sent out and shared on the PXI Star lines.  NI-DAQmx will check what you have set for a sampling rate (labeled as "Scan Rate" in your program), and divide down the SampleClockTimeBase rate appropriately. 

The AI Start Trigger is being sent from the PXI-4472 in slot 2.  This trigger is being routed on the PXI Trigger line.  We don't configure which line to use, NI-DAQmx picks one for us.  According to the documentation, we should not be able to share triggers across PXI segments if we have configured the trigger lines to be Dynamic.  However, our testing has confirmed that the AO device (in slot 😎 is indeed receiving the AI Start Trigger from the PXI-4472 in slot 2.  These of course are in different PXI segments, so this should not be possible (according to the documentation). 

I can think of two possibilities here.  Number 1, the documentation may be incorrect.  Number 2, since we are channel expanding with DSA then somehow NI-DAQmx recognizes the need to reserve all the trigger lines to allow signal routing across PXI segments.  I will look into this and confirm.  Thanks for being so patient golubovski!

[golubovski]

RT4CY,

Thank you and especially Brooks for the patience in clearing out my problem, and helping me come up with a solution. I look forward to your findings for you may recall how intrigged I was with my move from the Traditional NI-DAQ to the NI-DAQmx.

Sincerely,

[RT4CY]

Hey golubovski,

I have confirmed that the "Dynamic" setting will allow you to share triggers across PXI segments as long as you are using NI-DAQmx.  If you are using PXI modules that use NI-VISA or non-NI hardware, you will need to explicitly configure the trigger routing in the Triggers tab (in MAX).  I am glad that Brooks was able to find a resolution for you, and that we were able to clear things up for you.  Let me know if you have any additional questions.