Routing clock PXIe-6674T backplane?

[Mystogan]

Hi all,

I would like to know the easy way to route clock that I generate using PXIe-6674T into other devices in chassis, through backplane (without SMA cable)?

I'm using this example from NI: Generate DDS Clock, Divide & Route.VI.

I'm using PXIe 1082 chassis, and wondering if I can route 40MHz clock from 6674T into other PXI devices without using SMA cable, is it possible?

I'm not really understand about routing clock/trigger into:

PXI_STAR

PXI_DSTARA (I've read, it can send clock signal into other PXI devices in chassis)

PXI_DSTARB

PXI_DSTARC (same as B, it can send trigger signal into other PXI devices in chassis)

Any good explanation how does it work?

Regards,

Yan.

[crossrulz]

One of the great things with PXI is the backplane trigger and clock routing.  That example looks like a good one for routing your clock around.  The hard part is having your other instruments look at the clock (usually with the trigger settings of the instrument).  I would probably just use the PXI_Star bus.

[Mystogan]

I'm using PXI 5105 for Digitizer, and it has possibility to use sample clock source VAL_PXI_STAR,

but somehow I don't get how to route clock from 6674T using that VI, should I route the generated clock into PXI STAR? which one? 😞

I can use PFI1 (*with SMA cable from CLKOUT 6674T into SMB connector on 5105 PFI1) as sampling clock with using property node: Sample Clock Timebase Source, with parameter: VAL_PFI_1.

But I can't use and even still not understand how does PXI STAR works.

Regards,

Yan.

[crossrulz]

You should be able to specify which PXI-Star bus for both the 6674T and the 5105.  If you aren't using any, just use 0.

The PXI STAR is just a routing on the PXI backplane.  You connect the clock to the bus and tell the digitizer to look at the bus for the clock source.  Now, I should ask which slots your are using since the STAR bus only connects certain slots together.  I'd have to do some digging to figure out which slots are connected to each other via the STAR bus.

[Mystogan]

Hi,

I'm using chassis PXI 1082 and my digitizer PXI 5105 is in slot 6, from datasheet I should use PXI STAR 4 or PXIe DSTAR 9 to route this clock from my 6674T into my digitizer.

But then, I'm using property node of PXI 5105 to choose my SampleClockTimebaseSource, I don't know what should I put there. For PFI1 is easy: VAL_PFI_1. But using PXI STAR, I dont know.

Regards,

Yan.

[crossrulz]

Ok, after playing with the synchronization VIs, it looks like you have to use the DSTAR9 to send the clock.  The STAR is only good for triggers.  I'm guessing (from information found here) that you will want to use VAL_PXI_STAR for the clock timebase source.

[Mystogan]

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@crossrulz wrote:

Ok, after playing with the synchronization VIs, it looks like you have to use the DSTAR9 to send the clock.  The STAR is only good for triggers.  I'm guessing (from information found here) that you will want to use VAL_PXI_STAR for the clock timebase source.

---

VAL_PXI_STAR Without 9 ? I'll try that tommorrow. *at home already*

Thanks,

Regards,

Yan.

[Mystogan]

hi,

I've tried to route the clock into PXIe_DStarA9 in Generate DDS Clock, Divide and Route.vi and then use VAL_PXI_STAR as source of my clock on PXI 5105 and didnt work. I'm getting this error:

Fehler -1074118501

"There was an error with the hardware clock. If you use an external reference or sample clock, make sure that it is connected properly and satisfying the conditions on jitter and voltage levels. Also check whether the rate is the specified clock rate. If you generate your timing signals internally, you should contact National Instruments."

statuscode -233407

Did I miss something?

Regards,

Yan.

[CharlesD]

DStarA clock lines can only be used by PXIe (PXI Express) Devices.  The 5105 only has a PXI Variant therefore sending a clock on DSTARA is not useful for 5105. You will have to send a clock on either the PXIStar Trigger lines or PXI Trigger Lines.. 

Look at the 5105 device routes in max for more info on where the 5105 can receive clocks from. 

Hope that helps!