PXI-6602 or PXI-6608 signal routing to PXI_Star

[wired]

Is there any way to route a counter output from the PXI-6602 or PXI-6608 board to the PXI_Star bus?  I thought this would be possible, with it being in slot2.  I tried to do a device route from a PFI pin on the 6602 to a device's PXI_Star, then I tried to use that PXI_Star as a Timebase Source for a PXI-4472 DSA, but that caused Labview to throw an exception and crash.

[Jesse_O]

Hello,

The PXI-6608 is not able to connect to the PXI Star line with a counter output.  If you perform a connect terminals with the source being a counter output and the destination being the PXI Star line, you should receive an error saying that the route is not available.

If you are wanting to generate a clock output for the DSA device, you can export a counter output directly to a RTSI line.  If you are concerned about the transmission lengths/propagation delay of the RTSI line, you could use the 4472 to drive the PXI Star line in Slot 2.  For a better list of what devices can drive PXI Star, you can refer to the online knowledge base found here.

Another point of interest is that the 6608 is capable of driving the PXI Star line but not from a counter output.  If you look at the user manual on page 21 you can see that a clock is exported to PXI Star.

I hope this helps get you started.  If not can you please post more information about what you require for your setup?

Regards,

Jesse O.
Applications Engineering
National Instruments

[wired]

Figure 3-8 of the NI 660x User's Manual clearly shows the PXI Star line able to be used for signal routing an Internal Clock output.  I just purchased a PXI-6602 and a PXI-6608 based on the information in the User's Manual and in the NI 660x Specifications, which both show the PXI_Star as accessible.  This is not good news.

In my application, I am trying to replace a ZTEC ZT1000PXI card, which I had in slot 2, with the 6608.  The ZTEC card was outputting a programmable sample rate timebase for the 4472s on PXI_STAR, a programmable external sample clock to my PXI-6120s on PXI_TRIG2, a Start Trigger on PXI_TRIG3, and a Sync pulse to the DSAs on PXI_TRIG5.  It was also performing some other GPS-related functions.

Based on the documentation for the 6608, I thought it would provide all of the capability of the ZTEC except for the GPS functions. It appears this is not the case. Of course, it begs the question of WHY one would design a card with the precision OCXO for use in slot 2 and NOT provide the ability to generate a signal on PXI_STAR.

Regarding your suggestions:

I can't use a 4472 to generate the clock fo rthe slaves, because it would require it to be in Slot 2, which defeats the purpose of having the 6608 (precision timebase).

Also, I don't see how I can output the DSA clock on a RTSI line. The way I read the data sheet, it will ONLY accept a timebase from the PXI_STAR line.

[wired]

Trying a different approach now... Since I don't need the 10MHz clock on the backplane, I thought I'd running with the PXI-6608 in Slot 3 rather than slot2.

I routed one of the counter outputs from PXI1Slot3/PFI36 to PXI1Slot3/PXI_Star using the route signal VI, and was able to successfully run the attached PXI-6608 Set Frequency VI.  I then ran a test vi which uses a PXI-6120 to perform a finite data collection using PX1Slot3/PXI_Star as its sample clock timebase source.  This works - I am able to vary the frequency from the 6608's counter output and see a corresponding change in my finite collection time with the 6120. This tells me that the 6608 is capable of driving the PXI_Star line, at least when in Slot 3.

I then tried to do the same thing with the PXI-4472, and specified the SampClk.Timebase.Src as PXI1Slot3/PXI_Star.  When I run the VI, I get the following dialog box to pop up, and when I click on the OK button, LabVIEW completely locks up:

An exception occurred within the external code called by a Call Library Function Node. This might have corrupted LabVIEW's memory. Save any work to a new location and restart LabVIEW. VI "PXI-6608 Test 4472 Acquisition.vi" was stopped at node "" at a call to "DAQmx Start Task.vi:3"

I have attached the three test VIs for reference. 

Message Edited by wired on 08-20-2007 09:07 AM

[Sandra_T]

Hello wired,

Thank you for posting your vis. I will continue this thread through the phone e-mail and post back here once the issue is resolved.

Regards,
  Sandra T.

Applications Engineer | National Instruments