We need to aquire analog and frequency signals from two DAQ cards. The signals MUST be synchronised by the rising edge of one of the frequency channels

[trundel]

We need to aquire analog and frequency signals from two DAQ cards. The signals MUST be synchronised by the rising edge of one of the frequency channels.

[JRA]

Are these National Instruments DAQ Cards? If so, then you can definitely do this. The best way would be to use the RTSI bus. There are some really useful examples that come with LabVIEW which could get you started in this direction.

This Knowledge Base from NI's website can get you started with concepts of the RTSI bus. Then you should check out some of the examples. There are many that ship with LabVIEW and then you can find even more at NI's Developer Zone.

[trundel]

Thank you for that. Yes they are NI Cards and the cards themselves have been RTSI sync'ed. What we need is to start logging data from analog (16 channels)and frequency (up to 4 channels) signals at the same time, possibly using the rising edge from the frequency signal to start and stop logging data to a file . The problem is that we are not sure how much data we lose from the anolog signals (16 channals worth) relative to the frequency signal which is gated at 1 sec, (ie at the begining and end of the logging to file), if these signals are not sync'ed. Ideally it would be perfect to count the number of rising edges ,recording both time and # of counts and dividing them at the end, but this has proven very difficult to maintain accuracy as well as trying to
log analog data to file.