Data acquisition

[Jean-Michel Pichavant]

spintronic wrote:
> Dear friends,
>
> I have a trouble with understanding the following. I have a very short
> script (shown below) which works fine if I "run" step by step (or line
> by line) in Python shell (type the first line/command -> press Enter,
> etc.). I can get all numbers (actually, there are no numbers but a
> long string, but this is not a problem) I need from a device:
>
> '0.3345098119,0.01069121274,0.02111624694,0.03833379529,0.02462816409,0.0774275008,0.06554297421,0.07366750919,0.08122602002,0.004018369318,0.03508462415,0.04829900696,0.06383554085, ...'
>
> However, when I start very the same list of commands as a script, it
> gives me the following, which is certainly wrong:
>
> [0.0, 0.0, 0.0, 0.0, 0.0,...]
>
> Any ideas? Why there is a difference when I run the script or do it
> command by command?
>
> ===========================
> from visa import *
>
> mw = instrument("GPIB0::20::INSTR", timeout = None)
>
> mw.write("*RST")
> mw.write("CALC1:DATA? FDATA")
>
> a=mw.read()
>
> print a
> ===========================
> (That is really all!)
>
>
> PS In this case I use Python Enthought for Windows, but I am not an
> expert in Windows (I work usually in Linux but now I need to run this
> data acquisition under Windows).
>   

Just in case you have a local installation of visa and it silently fails 
on some import,

try to add at the begining of your script:
import sys
sys.path.append('')

When using the python shell cmd line, '' is added to sys.path by the 
shell, that is one difference that can make relative imports fail in 
your script.

If it's still not working, well, it means the problem is somewhere else.

JM