Digiatal pre-trigger over RISI w/NI PCI-6123 DAQmx

[johnfr]

I have an application which I need to aquire pretriggerded data using a PCI-6123 via RTSI bus from a channel on PCI-6052. Am aquireing a total of 7 channels, 6 on the PCI 6123 and 1 on the PCI 6052.  I am using DAQmx. Has anyone successfully achived this?

[TiTou]

Hello,

I'm not sure I fully understood what you need... What is you trigger source ? Is it going to be continuous or just a one shot measurement ?

If the hard point is about how to set the trigger to be RTSI channel, I saw a few examples in "Help" >> "Find example" and search for "rtsi"... I haven't used then but I assume they can be of interest for you.

Hope this will help you.

[johnfr]

Sorry I didn't make that clear. The trigger source is an analog trigger from the input channel on the PCI-6052. This is a one shot aquire. I am doing a modal tap hammer test which the channel on the PCI-6052 in the input from the tap hammer. The other six channels are from a 6 axis force transducer. Sampling of all 7 channels must be simutainiously sampled.

[Otis]

Hi John,

First you will need to connect your cards with a RTSI cable and then create that cable in MAX.

Sounds like all you need to do is a multi device synchronization. You can find examples for doing that by going to
Help > Find Examples > Hardware Input and Output > DAQmx > Synchronization > Multi Device

Once you see how to synchronize multiple devices you can either share the sample clock, or share the trigger.

In your case I think you will want to share the trigger over the RTSI line.  For the 6052 it sounds like you want to do an analog start trigger.  For the 6123 though you said that you want pre-trigger samples.  That means you will have to set up a Reference Trigger for the 6123, and then have it trigger off of the ai/StartTrigger signal from your 6052. 

You can find all of the examples with triggering in a similar path as before:
Help > Find Examples > Hardware Input and Output > DAQmx > Analog Measurements

Sharing the signals is a breeze and most everything is done automatically by the DAQmx drivers. 

For more details on synchronization check out this Tutorial:
Advanced Data Acquisition Series - Synchronization with NI LabVIEW and NI-DAQmx