USB DAQ synchronization

[Corey867]

I am working with LV 2011 and multiple 6210 DAQ USB devices (and I do not have the option of using only one device).  I am trying to get the multiple devices to start data acquisition on one digital start trigger. My hope was to physically connect a digital output line of device 1 to a digital input line of device 3.  In my code I would use the DAQmx Start Trigger VI to tell Dev1 and Dev2 to start collecting data when the line on Dev3 goes high.  The software would drive the digital output line of Dev1 high. 

Unfortunately this does not work.  I get "error 89125: No registered trigger lines could be found between the devices in route".  I have searched through parts of the KnowledgeBase but I am still lost.  The information I've found on doing something like this with USB DAQ boards does not seem to fit my situation close enough for me to make the connection between the example and my application.  Any help would be appreciated.

Thanks.

[GregFreeman]

What line is your trigger source coming into? A digital or a PFI line? I would also suggest trying to get one device to work from an external trigger before trying to tackle multiple devices. Have you looked at any external trigger examples that are not necessarily USB DAQ? If you are restricting yourself to only USB DAQ examples, it may be harder to find what you're looking for.

[Corey867]

I am using a PFI line (all of the digital lines on the 6210 are referred to as PFI, 4 input only, 4 output only).  I have used one device in the past with a digital trigger with no problem.  My resources are limited to using USB DAQs.

[kusg]

I experience the same problem here (perhaps due to my little understanding on the daq concept) -- I am using NI USB DAQ with no support for synchronization but support only for triggering (analog / digital).

Using DAQmxCfgDigEdgeStartTrig to configure, this gave no error until I try to start on the slave task handle. Any pointer would be helpful. Thanks.

[Aldo_A]

Hi kusg,

here is a great tutorial mentioning the DAQmxCfgDigEdgeStartTrig configuration:

http://zone.ni.com/devzone/cda/tut/p/id/5409

If possible, could you post your code so I can better understand your problem?

[kusg]

Thanks Aldo. I started a new thread, with a more specific question and I have included the sample code on this post: http://forums.ni.com/t5/Multifunction-DAQ/NI-DAQmx-C-for-running-two-USB-M-Series-Card/td-p/1792544