PXI-6541 triggers on backplane.

[ianhf]

Hi

I am trying to implement a digital test system using the 6541 to generate and aquire digital patterns.

I would like to put a digital signal channel from the generation side of the 6541 onto the PXI backplane and read it back of the backplane as a Start trigger signal.

I would like to do the same thing with the Pause trigger signal as well.

Is this possible and has anybody managed to do this with the 6541.

Thanks

Ian

[Mert_A.]

Ian,

You may want to also post this question to the PXI forum, if you have not already done so.  You may get more expert advice there.

Mert A.
National Instruments

[Ryan_M]

Ian,

The PXITRIG(7..0) are available for all SMC based devices (such as your 6541) for trigger and event routing.  For example, you can use the "niHSDIO Export Signal" vi to route a Data Active event to PXI Trigger Line 0 and have a second device configure an edge based Start Trigger with a soruce of PXI Trigger Line 0.  In this fashion, the first device will start and export the data active which will then start the second device.

The user documentation in the Triggers and Events section has a more complete set of available signals that can be routed to the various trigger lines.

[ChrisNI]

Hey ianhf - I think there's a way to do what you want, but with a slightly different method than routing a data line to the PXI backplane.  Data lines can only be driven out of the DDC Connector on the front panel of the device - they cannot be routed to the backplane.  However, exported events can be, and they have the added benefit of not using up one of your data lines.  There are two events that might get you what you need.  The first is DataActive - it's a level event that is asserted whenever you're generation session is running.  Thus it toggles at the start of the generation.  This could be routed to the PXI backplane to trigger a start condition on another device.

Another type of event is a marker event.  You can configure and control markers by using scripting on the 654x.  Scripting allows HW timed linking/looping of multiple waveforms, but also allows you to generate a pulse whenever a certain point in a waveform is reached.  You decide where in the waveform you want the marker to occur.  A marker could be setup to pulse at multiple arbitrary positions within a waveform.  Check out the following example that shows how to export a marker event

.../cvi/samples/nihsdio/dynamic generation with script/DynamicGenerationWithMarker/DynamicGenerationWithMarker.prj

This example routes the marker event to PFI0, but by changing the markerDestination to NIHSDIO_VAL_PXI_TRIG0_STR (a.k.a. "PXI_Trig0") you could route it to PXI Trigger Line 0 on the backplane.  There's also pretty thorough documentation on the scripting language in the help file.

I hope this helps,

Chris