Creating a field output for every frame of a step

[Cucurrucucu]

Dear friends:
Please excuse my bad english.
I'm using Abaqus 6.6-3.
I want to create a field output consisting of a mathematical operation between variables -lets say "abs (S max principal - S min principal)". That is very easy to do for a concrete frame (TOOLS > Create Field Output > From fields). But I want Abaqus to calculate that field output for each and every frame of the step (there are 100 frames in the step I desinged). Is there a way of doing that automatically?
Thank U for your help!

 

[xerf]

You can use ABAQUS Scripting Interface.
See for example
ABAQUS Scripting User's Manual -> 8.8 Computations with ABAQUS results