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 DeviceOnce 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 MeasurementsSharing 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