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hardware timed raster scanning of analog out

First, an overview of what I'm doing:  I've recently workedout hardware-timed counting of ttl pulses (from a photon counter) with short integration times (~1ms).  Now I would like to include raster-scanning of a 2-D piezo stage while collecting TTL pulses.  I did this a while back using software timing for >10ms integration times, but now I would like to speed things up.  I have a pair of pci-6014's to work with, and am doing everything with DAQmx and LabView. 

The attached file raster_scan_ishapiro.vi is the scanning excerpt from my full Labview vi, rasterscan_v3.vi.   The full vi includes synchronized hardware-timed buffered pulse counting.  I use a pulsetrain generated by dev1/ctr0 and physically routed to dev2/PFI0 to time the counting by dev2/ctr0 and dev2/ctr1.  To do the fast-axis scanning, I am also using the pulsetrain to time Dev2/ao0.  Dev2/ao0 voltage output presently consists of a "Analog 1D DBL, 1Chan NSamp", and the data is a 1-D array of linearly-spaced voltage values (generated by the sub-vi create_fast_axis_waveform_ishapiro.vi). 

When I run this vi I don't see any errors.  The problem is that the fast axis does not appear to scan.  Even if I slow down the dwell time so that the motion of the peizo stage will be visible (through a microscope), I only see the slow  axis stepping through a series of points.  All the images I've collected also indicate that the fast axis is stationary.  I've racked my brain over this one for a while now and can't figure out the problem.

Can anyone tell me what's wrong with the way I've set up my hardware-timed analog output? 
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