Synchronizing Two 6602 Cards

[MikeGI]

Hi,

I have two 6602 cards connecting with an RTSI cable.  I have succusfully triggered each card individually to count periods on all 8 counters.  However, I need to trigger both cards to count simultaneously on all 16 counters.  Which DAQmx functions should I be using to achieve this?

-Mike

[Matthew_W]

Mike,

The DAQmx function you are looking for to synchronize the two cards is a ArmStart.TrigType.
 
 Here is a forum post where this same problem is discussed, example code and pictures included!

 This KB talks about synchronizing counters using the ArmStart trigger.

 
Hope this gets you going!

Best regards,

MatthewW
Applications Engineer
National Instruments

Message Edited by Matthew W on 07-13-2007 04:17 PM

Message Edited by Matthew W on 07-13-2007 04:18 PM

Message Edited by Matthew W on 07-13-2007 04:19 PM

[MikeGI]

Thanks for the response, Matt,

Unfortunately I am not using Labview, so vi's do not exactly help me out.  I am coding through Matlab.  I should have specified that.  I have already been using the Arm Start Trigger, though, to successfully trigger 8 counters on a single card.  If I wanted to trigger 16 counters on 2 cards, do I have use an additional DAQmx function, or are the cards able to automatically access each other through the RTSI cable?

Mike

[rpurser]

Hi Mike,

Are you using Data Acquisition Toolbox, or MATLAB's generic DLL support to access NI-DAQmx directly?

-Rob

[MikeGI]

I am using nicaiu.dll and NIDAQmx.h to access the DAQmx functions

[rpurser]

I think Matthew's post earlier probably has all the info you need, then.  You'll need to look up the C API calls that map to the methods he mentions in the NI-DAQmx C reference, but that's pretty straightforward.

-Rob

[MikeGI]

Hi Rob,

From what I read in the above posts and the attached links, I did not see anything referring to triggering two counters on seperate cards simultaneously, only counters on the same card.  Do you use the same calls to trigger two cards that you would for only one card?

-Mike

[Matthew_W]

 Hi Mike,

 To use the RTSI connection between the cards you will have to register the RTSI cable in MAX first.
This article: http://zone.ni.com/devzone/cda/tut/p/id/4322#toc6 discusses how to do that under the Routing Signal Options header.

  Why aren't my triggers working over RTSI?
  http://digital.ni.com/public.nsf/allkb/80E6951BFAD98DE686256D0A003CDC47?OpenDocument

Where is Select_Signal help?
  http://digital.ni.com/public.nsf/allkb/A120195AAAA9222A86256C69007C8B27?OpenDocument

Discussion of triggering multiple cards over RTSI in textbased programming:
  http://forums.ni.com/ni/board/message?board.id=250&message.id=468&requireLogin=False

  Have a great week Mike!

 MatthewW
 Applications Engineer
 National Instruments