LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

Synchronisation PTP/ Synchronisation NI 8383mc

hello,

 

I am currently working with two PXI châssis.

I am trying to synchronise these two châssis by using two different methods:

 

-Method NI 8383mc with PXImc cable connecting my two châssis. After installing the necessary drivers on both châssis, is there additionnal action to complete

 

-Method PTP: I am trying to synchronise châssis using PTP connection. How do I configure my NI MAX and my châssis for garuanteeing my two châssis are based on the same clock?

 

For each method, it is possible to realize these synchronisation using LabVIEW programming instead of configuring NI MAX?

 

Thanks for your Help

 

Paul MM

LabVIEW Developper

0 Kudos
Message 1 of 6
(3,642 Views)

Hi,

 

Could you explain a bit more about what you are doing in the first method and hoping to accomplish?

 

As far as the second method, PTP synchronization uses the Best Master Clock Algorithm to automatically select a master on the network. All PTP clocks on the network will then sync to this master. Are you experiencing an issue where more than one clock on the network is being chosen as the master?

 

As for configuring synchronization in LabVIEW instead of NI MAX, this is certainly possible. I’m assuming you’re using the NI-Sync driver with either a PXI-6682(H) or PXI-6683(H)? If that’s the case, there are several examples that ship with LabVIEW that should help you get this set up. In LabVIEW, go to Help>>Find Examples and then Hardware Input and Output>>Timing and Synchronization>>Time-Based. The “Set Time Reference” example will allow you to set 1588 as the time reference for your board. The “Start 1588 and Wait for Quality” example shows how to start 1588 and wait for the clock to get to steady state.

 

From there, if you’d like to discipline the backplane clock of your chassis, the method of doing so will depend on the hardware that you have. If you could give me more information on your hardware, I could provide a recommendation.

0 Kudos
Message 2 of 6
(3,566 Views)

Hi LindsW,

 

Thanks for your answer, it has been very helpfull so far.

 

To explain furthermore what I am trying to do

I am working with 2 x NI 1085 PXI châssis with several cards PXI cards inside them.

 

In the fist one, I synchronise clock of the châssis using different ways (it could be synchrnisation NTP or synchronisation via Ni 6683H card).

The 2 châssis should have the same clock, so we were thinking to synchronize the clock from the first châssis with the second. And for that, 2 solutions were brought:

-using NTP communication (This solution hasn't been experienced yet)

-using NI8383mc card for synchronization via MXI connection (Not experienced yet)

 

Our hardware is NI PXI 1085 châssis with a  NI 8135 contrôller.

 

Thanks

 

Paul

 

0 Kudos
Message 3 of 6
(3,545 Views)

Hello again,

 

It sounds like you’re considering three options: synchronization via MXI, NTP, and PTP. Here are some thoughts on each of those options:

 

  • MXI Synchronization: It’s not possible to synchronize two chassis via MXI as you are describing. MXI cannot carry triggers between the two chassis.

  • NTP: The PXI-6683H does not support NTP. This type of synchronization would take place solely in software on your controller. This would allow you to synchronize an embedded controller to an NTP server, but would not synchronize either chassis’ backplane.

  • PTP: This sounds like your best option at this point. You can use a PXI-6683H on each chassis and connect them with an Ethernet cable. Then install the NI-Sync driver and run the examples I mentioned above to achieve synchronization between the boards.

    Once you have the boards synchronized, you will likely also want to synchronize the backplane clock of the chassis. Since the PXI-6683H is a hybrid card and does not fit in the system timing slot, you cannot do this directly. You will need to use the niSync Connect Clock Terminals VI to connect the Oscillator to ClkOut (this routes the oscillator on the board that has been disciplined by the 1588 timing source to the ClkOut connector on the front of the board). Then use a cable to connect ClkOut from the board to the Clk10_In of the chassis to override the backplane clock.

 

Since it sounds like you’re looking to architect a new system, I’d highly recommend reaching out to your NI Sales representative and/or NI Support, as they will be able to give you more in-depth recommendations. Feel free to send me a Direct Message through the forums if you need help contacting the right person!

0 Kudos
Message 4 of 6
(3,515 Views)

Thank for your quick answer LindsW,

 

Concerning the three possibilities:

 

In our system, we have 2 chassis communcating between them. In the first chassis (Master) we have three solutions to synchronize chassis:

-NTP synchronisation, using 1085 embedded controller

-IRIG-B or GPS synchronisation using NI PXI 6683H

 

Indeed The MXI card is not used for synchronizing 2 chassis, but for exchanging data between them (my mistake).

 

On the contrary PTP is a solution for synchronizing 2 chassis together:

But I am not sure how to use the LabVIEW examples to configure and synchronisation by PTP, which example would you use for PTP communciation?

 

Thanks

 

Paul

 

 

 

 

 

0 Kudos
Message 5 of 6
(3,477 Views)

Hello,

 

To configure PTP, you will need a 6683H in each chassis, and will need to connect the 6683H's via ethernet (either directly or through a 1588 switch). You can then configure the synchronization in NI MAX or LabVIEW. From your earier post, it sounds like you're looking to do it in LabVIEW. In this case, you can use the LabVIEW examples I mentioned previously:

 

"In LabVIEW, go to Help>>Find Examples and then Hardware Input and Output>>Timing and Synchronization>>Time-Based. The “Set Time Reference” example will allow you to set 1588 as the time reference for your board. The “Start 1588 and Wait for Quality” example shows how to start 1588 and wait for the clock to get to steady state."

 

Run both of these examples on each 6683H.

0 Kudos
Message 6 of 6
(3,436 Views)