how to continuosly acquire data with analog pre triggering

[V]

I am trying to acquire analog data with pretriggering capability on a continuous basis (Cont. Acq&graph voltage-Int Clk-Analog Ref).   I am just now switching over to DAQMX so I am not that familiar with its capabilities.  I have a simple program I have written in DAQMX that is set up for Analog ref and the start read and stop task are written in a while loop to accomplish a continuos acq.    The program works for E series card (6032) but not  M series card (6251), I am skipping a lot of the pulses.  For example I am feeding in a 5 V TTL signal at 100 Hz to AI0.  With the E seires card  this program acquires all 100 pulses a seconds, while with the m series card the program acquires only 20 pulses or so.  The time delay betweens acq seems to be long?  I am attaching the labview code.

thanks for your help

V

[altenbach]

Please keep it all in one place: http://forums.ni.com/ni/board/message?board.id=250&message.id=18226#M18226