Hi Tommy,
i assume you have a sync port on PCMCIA Can Card and you have terminal block on the USB DAQ Card.
note the comment i have taken from the example VI from NI:
Enable FREQ_OUT to 10MHz.
Use CAN Sync cable to physically wire DAQCard's FREQ_OUT to PCMCIA-CAN RTSI7 (TRIG_CLK).
refer to example: 'Multiple CAN Cards Frame API Single DAQmx Card.vi'
Hope this helps you. good luck.