slaine,
I don't have a full answer, but maybe about half of one. The first point to emphasize is that any hw-timed signal you'd like to share across RTSI needs to be created by the hw resources of your boards (internal clocks, programmable counter/timers).
Between your 2 DAQ cards you have 4 counter/timers that can be used to generate the timing signal pattern you need. If I understand correctly, you should be able to accomplish the clock and pulse pattern with either 2 or 3 counters. These counter outputs can easily be exported to the RTSI bus to be shared. I don't know CAN well enough to comment on syncing the messages with specific RTSI pulses.
Example 1: generate a 250 Hz pulse train with one counter and then create a 50 Hz pulse train on another counter by "dividing down" the 250 Hz clock. This would necessarily space the messages equally in time at 4 msec.
Example 2 (if you need bursts of messages spaced, say, 1 msec apart): create a 50 Hz pulse train and a 1 kHz pulse train that uses the 50 Hz pulse train as a "Pause Trigger." The result of this "Pause Trigger" mode is similar to a logical AND of the two pulse train outputs. By carefully choosing the "high time" of the 50 Hz pulse train, you can choose the # of 1-msec-spaced messages to be sent.
-Kevin P.
CAUTION! New LabVIEW adopters -- it's too late for me, but you *can* save yourself. The new subscription policy for LabVIEW puts NI's hand in your wallet for the rest of your working life. Are you sure you're *that* dedicated to LabVIEW? (Summary of my reasons in this post, part of a voluminous thread of mostly complaints starting here).