You can in fact create graphs on the V230. I figured it out from the function block manual's discussion of the Trend function.
http://www.unitronics.com/data/uploads/VisiLogic_Software/VisiLogic_Software_Manual-Function_Blocks.pdf
I am looking to plot a curve on the PLC so that we can see once our system has reached a steady state condition. Is there any way on the Vision 230 PLC to display this kind of graphic? Thanks.
EDIT: Figured it out. Looked at the Trend examples.