Parametric study- PSF file - XY plot

Dear all,

I'm a new Abaqus user. Due to my project, I have to run some parametric analysis. For each of these analysis I need to plot the displacement for the entire last step. To run rapidly the same jub but with different values of some parameters, I'm using the *parameter card.  The problem I have, maybe you can help me, is that, by writing a .psf file, I am not able to plot (or to "print") the result for each increment of the step I need. This is my psf file:
dy = ParStudy(par='dy1', name='Istatedy')
dy.define(CONTINUOUS, par='dy1', domain=(-0.7, -1))
dy.sample(NUMBER, par='dy1', number=5)
dy.combine(MESH)
dy.generate(template='Istatedy')
dy.execute(ALL)
dy.output(file=ODB, instance='Part-1-1', request=FIELD)
dy.gather(results='n4_u', variable='U', node=4, step=4, inc=15) 
dy.report(PRINT, par='dy1', results=('n4_u.2'))

if I indicate one increment , for example inc=15, it gives me just the displacement of the node 4 for the increment 15. if "inc" is missed, it gives me the results just of the last increment, by default. So, I do not know how to tell python to print me a table with the results of each increment in order to plot the result of the entire step. 
Do you have any suggestions to do that? Also by means of different method. Should I try with iSight?
Please let me know if you could give me some any help