I found a different problem with the SCXI-1520.  After a device reset in DAQmx,  if you change the E-series master timebase, then occasionally some of the  channels on the 1520 will be programmed with the wrong gain.  The attached VI  shows the problem.  I'm using a PXI-6030E, SCXI-1520, and a PXI-6651 to route  the PXI_CLK10 signal to PXI_TRIG_7 for the MIO.  If I use a "commit" after  configuring the channels but before changing the master timebase, it seems to  work correctly.  I suspect the problem would also happen after a clean powerup  without the device reset but that would take a lot longer to  reproduce.  This is with NI-DAQmx 8.8 and LabVIEW 7.1.1.
 
-Bob W.