Triggering Multiple Boards (RTSI/PXI) with Analog/Digital Trigger and Delay

[F._Schubert]

I'm syncronizing multiple boards (M Series) for AI and AO with analog or digital Start trigger.

The first approach was (RTSI system with digital triggering):
* I used the digital trigger on PTFI0 for the ai0 task as start trigger and then routed the ai/StartTrigger to the other boards. Syncronsation failed, the other boards started aquisition/output before the trigger. I guess the start trigger was set when I started the task (to wait for the trigger).
* I solved this problem by routing the Dev1/PTFI0 trigger to all other boards.

Now, for a different setup (PXI), I will use an analog trigger using Dev1/ai0, which will also be a monitoring channel, started by that trigger. Which signal do I now route as trigger signal for the other channels/boards?

To complicated the issue further, I'm using a delay (StartTrigger.Delay). I already found out, that this delay will happen after the start trigger is set, so in the setting above I had to set the delay for each channel. How will that work in the second setup?

And furthermore concerning the delay, how good are the delays of all channels syncronized? I use a shared sample clock (either OnboardClock of Dev1 or for PXI the 10MHzRefClock)? Or would it be better to set a second trigger signal after the delay (as a seperate DO task) for all AI/AO tasks, to start them sync'd?

Felix

[Wolfgang_Z.]

Hello Felix,

In this Knowledge Base http://zone.ni.com/devzone/cda/tut/p/id/3615 you can find examples how to synchronize M-Series Boards (simultaneous start and clock synchronization).
Especially to your problem look for Synchronization Using the Reference Clock (Figure 5 for PCI and Figure 6 for PXI) and Synchronization of two M Series devices using sample clock (Figure 7).
You can download all examples at the bottem of the KB.

Further you should check the example "Multi-Device Synch-Analog Input-Finite Acq-Analog Start.vi". You can find it with LabVIEW Example Finder.

An example with Start Trigger Delay you can find here http://zone.ni.com/devzone/cda/epd/p/id/905. You need a Start Trigger Delay for both devices.
Please run example in KB. Then copy Start Trigger Delay poperty so that you have two Start Trigger Delay properties in VI (one for AI and one for AO).
Set the same delay time on both poperty nodes. You can see that you need a Delay for every task.


Regards,

WolfgangZ

[F._Schubert]

Thank you WolfgangZ. I forgot using the example finder. The examples provided there make it clear to me. The other resources you linked were already known to me.

Felix