Automotive and Embedded Networks

[Sparklejc]

Hi,

Just want to know if it's possible to synchronize series 2 PCMIA CAN/s or USB-8473s with USB-6229. If so how to connect the two setup together through RTSI connection? I assume I would follow the example VI "CAN Sync Start with NI-DAQmx". Thanks.

Jason

[Blayne_K]

Hello Sparklejc,

You can synchronize multiple USB 8473's with a DAQ device by connecting a clock either derived via a counter, or by utilizing a master timebase of the DAQ card and then routing this to RTSI7/RTSI Clock on the 8473. One can then used this RTS17 input to serve as the Master Timebase on the CAN card. This process is more fully elaborated in the following KB: http://digital.ni.com/public.nsf/allkb/D0EDC7D94E14EA4386257348006148DD?OpenDocument .

Best,

Blayne Kettlewell

[Sparklejc]

Hi Blayne,

Thanks for your reply. I used the reference design and connected it as follow. However I can see that the CAN and DAQ start is still not synchronize, I suspect I need to configure the startTrigger. Basically I want to it to start capturing analog and CAN data simultaneously when I start running. Analog signal will always be there, I suppose to set the trigger source to an analog input (AI0), when it start capturing, generate a pulse on the startTrigger to start CAN capture. How would I go about doing this?

From the USB-8473s to USB-6229

CLK -> 10Mhz pulse AO to PFI12

TRIG -> ai/StartTrigger to PFI0

GND -> DGND

I've attached a draft of my program.

Thanks a lot.

Jason

[Danny_F]

Jason,

When synchronizing NI-CAN with DAQmx, NI-CAN is acting as the slave because it is waiting for the trigger that DAQmx is creating. When synchronizing and using the "master/slave" architecture the slave must always be started first. This is so the slave task is started and waiting on the master task to start. When the master task starts it creates the "start trigger" that is recieved by the slave.

In summary you need to simply reorder the dataflow of your program so CAN starts before DAQmx.

Regards,

Danny F