Hi Guys,

Just spent 2 days isolating a very specific problem that I had when
using the SCXI 1125 module with the SCXI 1313 breakout board.

I set up an analog input virtual channel in old style DAQ (7.1 and the
latest version 7.2) and the corresponding global channel in DAQmx.

The old style daq channel worked fine, but the DAQmx channel just read
garbage.

Repeated support calls (yes we signed up for the subscription!) didn't
produce much help from NI.

I finally narrowed it down to the specific channel range I was choosing
(+/-15V).  The old style daq allows you to specify the individual gain
(on the specific SCXI 1125 channel) and attenuation (provided by the
programmable breakout board).
DAQmx does not.  It automatically sets both these parameters based on
signal input range.  However, it looked like it set up the attenuation
correctly, but the gain setting was probably wrong.


Work-around:  I had to use a daq channel on the PCI daq card instead,
with a potential divider to bring the signal voltage down to +/-10V.  
Changing the code back to old-style daq was not an option, this late in
the game.

Hope this saves someone else some time.


Cheers,


Neville Dholoo
Cellex Power Products, Inc.
Richmond BC
Canada


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