How do I assert a trigger on PXI 0?

[Clinton Thomas]

I was reading a post regarding the use of a Start Trigger with NI-SCOPE and decided that the approach taken there is exactly what I need for my solution. Here is a link to that post

http://forums.ni.com/ni/board/message?board.id=150&thread.id=1741

In this, he talks about using a trigger from a PXI line to initiate the continuous aquisition on his ADC. In my case, I would like to have the same trigger start both an ADC and a Waveform Generator. I am unsure of how to assert the trigger on whatever specific line I need to assert on. When I look at my hardware info in MAX, I see that my devices have the same PXI Bus Number, and there is a Trigger Bus number as well that they both share. After looking around I found the VISA Assert Trigger vi, but it seems like it wants to trigger a specific device, rather than a line on the PXI bus. How can I create the impulse on a single line of the PXI bus for use as a trigger for my two modular instruments?


CT

[S_Hong]

Hi Clinton,

When synchronizing our SMC based modular instruments, there are two main signals that need to be synchronized across the different devices: A common reference clock and a trigger clock (TClk). The 10 MHz PXI reference clock will be used as the common reference clock across the different modules to synchronize their derived clocks. On the other hand, the TClk signal is not shared by the devices but instead is internally generated by each device from the sample clock or sample clock timebase for that device and therefore they must be synchronized using a common Sync Pulse signal. Now we have an API which can take care of all this under the hood and this driver is the NI-TClk. By allowing the drivers to share the common reference clock between modules and compensating for the propagation delay of the PXI trigger lines such that each module receives a start trigger at the same clock edge, NI-TClk guarantees that each instrument will be tightly in sync with each other within a 1 ns of skew and even up to 20 ps of skew with extra calibration procedures.

So in essence, to synchronize multiple SMC based devices, all you need is to use the NI-TClk VIs. To learn more about how the NI-TClk API is able to achieve subnanosecond synchronization between multiple instruments, you can refer to Using NI-TClk to Synchronize Signal Generators as well as the NI-FGEN Help.

In order to better understand how to use NI-TClk, I have made a simple example synchronizing an Arbitrary waveform generator with one of our High-Speed digitizers. Note that the NI-TClk involves only three simple VIs. I have also set both the generation and acquisition to trigger off of PFI0.

Please let me know if you have any further questions.

[Clinton Thomas]

Hey,

So I cannot open this example. I do not have NI-FGEN installed. My waveform generator is using NI-HSDIO. Any way you could remake it with HSDIO? Thanks for pointing me to TClk, this seems like exactly what I need.


Clint

[S_Hong]

Hi Clinton,

I have replaced the NI-FGEN VIs with NI-HSDIO. Please let me know if you have any questions.