Hi Mike,
With the mentioned synchronization cable, the PCMCIA-CAN cards are able
to use four general purpose (digital) trigger lines as well as import a
10 MHz clock from any external source (e.g. to synchronize the
timestamping of CAN frames to the external device).
The NI USB-9233 does not provide any kind of external access to its
internal trigger/clock signals. Thus, the only way so provide some sort
of hardware synchronization would be to let the PCMCIA-CAN card
generate periodic (toggle) pulses (i.e. use the provided 10 Hz Resync
pulse) on one of its trigger lines and receive that signal with one of
the four inputs of the NI USB-9233. As the period of that pulse is
known, one can correlate the sampled DAQ data with the timestamps of
received CAN data and keep drift to a minimum.
As the NI USB-9233 cannot output any signals it cannot provide an event the PCMCIA-CAN card can react on.
While this is certainly not an elegant solution, there are better ways to synchronize the PCMCIA-CAN cards with DAQ devices.
The easiest way to synchronize the PCMCIA-CAN card with a DAQ device
is, when the DAQ device is able to export a 10 MHz clock signal (for
clock synchronization) as well as dedicated start trigger signals. This
applies to the PCMCIA DAQcards (Analog Output or Multifunction DAQ) or
the USB NI DAQPads (6015, 6016 and 6020E).
However, none of the above mentioned DAQ devices is a DSA device and
does not provide true simultaneous sampling or 24 bit of resolution.
For more information on the synchronization capabilities, please take a
look at the PCMCIA-CAN section of Chapter 3, NI CAN Hardware of the
NI-CAN Hardware and Software Manual (in particular pages 3-24 to 3-26).
-B2k
