Scilab Plots : axes ranges

The plots themselves adjust the axes ranges depending on the values of the data being plotted.
However, if you need to set the ranges fixed, then use the following code after your plot command.

{code}

g = gca();
g.data_bounds = [0,0;1,1];

{\code}

where, 

g.data_bounds = [xLowerLimit, yLowerLimit: xUpperLimit,yUpperLimit];

Peace.