i finally managed to start MONSA with the SAXS data from ESRF ID14EH3
here is how to proceed to prepare the data .dat files:
-1- subtraction of baseline with correction in excel /cut noisy area ( >3.4 nm^-1), normalise max. intensity to 1.
-2- create a .dat file with 2 columns with saxs data (>1300 points)
-3- run GNOM (hamburg ATSAS program package)
-4- edit the .out in excel to keep only the 2 first columns of data. (1300 points shrink to 447 points that monsa can digest)
-5- make it a .dat file. (ascii tabulated separated .txt to rename .dat)
if you use the .dat file from step 2, you will soon have the error that the "Abscissa is out of range" after starting the run. This medhod prevents it from happening.