How can I synchronize clock on multiple PXI devices?

[Mystogan]

Hi all,

I need help regarding clock-synchronization on multiple PXI devices.

I have PXIe 1082 chassis with:

PXIe 8370 (Controller) in slot 1

PXIe 6544 (HSDIO) in slot 3

PXIe 6674T (Timing Module) in slot 4

PXI 6733 (Analog output) in slot 7

PXI 5105 (Digitizer) in slot 8 

And I'm able to make 1 global start trigger with using RTSI O, which able to start all devices (which I'm using, without 6674T) at the same time.

But I dont know how to sync the clock. Which terminal can I use to sync the clock?

For example, I'm generating simply:

10MHz clock with HSDIO

1Mhz waveform Analog output.

And at the same time I'm acquiring with Digitizer with 10MHz rate.

how to sync them all? I would prefer without cables.  

regards,

Yan.

[Mystogan]

Anyone? Any hints? any pins?

[Joaquin90ty]

Hi Mystogan,

I want to help you out with your problem. I found some documentation, which describes the synchronization of multiple pxi-chassis with the 10MHz clock.

How Can I Synchronize the 10 MHz Reference Clock on Multiple PXI Chassis?

http://digital.ni.com/public.nsf/allkb/64154143B6B898AA86256C2B006D11CC?OpenDocument

Tell me if this information was useful for you and feel free to ask further questions.

Kind Regards,

Joaquin

[Mystogan]

Hi joaquin, thanks for replying.

Thanks for the link, but what I need to know, is how to distribute my generated clock (using PXIe-6674T, Timing module) in 1 chassis (PXIe-1082) to other peripheral PXI devices on the same chassis, without using much cables. I dont understand, I've read the manual specs of PXIe 1082, and it says, I can use my Timing device to export a generated clock into PXIe_CLK100.

But I've tried one example included with PXIe-6674T "Generate DDS Clock, divide and route.vi", and couldnt export the clock to PXI, I didnt find any PXIe_CLK100 pin.

[Joaquin90ty]

Hi Yan,

ah okay, sorry for misunderstanding. You can use the PXI_Clk10_IN to synchronize your devices in the PXI chassis. Does it work if you choose the PXI_Clk10_IN in your frontpanel, so you have 10MHz clock for synchronization? Attached is a quote of the specification of the chassis. I'm not sure if this is what you really want, but just tell me

Kind Regards

Joaquin

[Mystogan]

Hi joaquin, thanks for replying.

Too bad I'm not at workplace anymore so I cant test it at the moment.

Hmm, but what I'm trying to get is, how to make my generated clock (using 6674T) got detected from all other PXI pheriperal devices (on the list in my first post), so I can synchronize them all.

What I did until now, I can export my generated CLK from 6674T into its pin CLK_OUT, then with using cable, connect it to CLK_IN of my HSDIO (6544), then with using cable from CLK_OUT of my HSDIO device I make a connection to PFIO of Digitizer (5105). And I still dont get it, how to sync the clock to my Analog Signal interface (6733). I tought I should be able to connect them inside PXIe chassis, right? But I found only option that I can export my clock from 6674T to PXI stars pins, but I cant get the other interfaces use it.

regards,

Yan.

[Mystogan]

Hi joaquin,

I've tried to export my 20MHz clock into PXI_Clk10_In from Oscillator, and no error appears. But I still found 10MHz instead of 20MHz from the PXI_Clk10_In.

I just dont know how to get this PXIe_CLK100 pin to work, or ways to connect my clock to this pin.

Regards,

Yan.

[Joaquin90ty]

Hi Yan,

if you want to synchronize the listed devices, it isn't possible to use the PXIe_Clk100, because the analog output card doesn't support PXIe. We did some tests here and the synchronization with the 10MHz clock with PXI_Clk10_IN worked. I will try to explain you what we did step by step. 

1) Use the Generate DDS Clock, Divide and Route.vi to set the reference clock for the other devices (as you did). 10MHz are routed from the Oscillator to Destination Terminal PXI_Clk_10_In and the divided by 2 clock to the Destination Terminal PXI_Trig7 for the analog output card.

2) In the next steps you need to set the reference clocks for each device with the specific VI's. Therefor you can use the examples with a few modifications, which you can see in the attached screenshots. Use the PXI Clock as reference clock for the HSDIO and the scope card and use the PXI_Trig7 as mastertimebase (MasterTimebaseSrc-Property) for the analog output card.

I hope this explanation will help you to synchronize your devices and if you have further questions feel free to ask.

Regards,

Joaquin

[Mystogan]

Hi jo, thanks for your detailed explanation.

I think I've been able to sync my ref clock of HSDIO to PXI clock with using VI from your suggestion.

And so it is with PXI 5105. As I can use PXI clock as their reference source. I'm using those VI's you mentioned to communicate with PXI clock as reference. 

But I still get problem with 6733, I just cant get it work. I did as you told me, and I got my old unfinished problem back with this analog generation "Error -200018", which I've posted already (https://forums.ni.com/t5/LabVIEW/Need-urgent-help-with-Error-200018/td-p/2140014) and still unable to cut this problem out.

But thanks for your input, I really appreciated it.

Regards,

Yan.

[Mystogan]

Hi jo,

a quick question, the frequency to be synchronized through terminal PXI_Clk10_In can only be 10MHz? I've tried to change it to 40MHz, but I just noticed that I found out 10MHz from the BNC out of 10MHz REF from behind the PXIe-1082 chassis. Its not the same pin?

Regards,

Yan.