The function plot.plsreg2 displays four plots:
1) the circle of correlations between the variables and the first two components (scores)
2) the plot of weights and loadings (w,c)
3) the plot of components (t1,t2) and the plot of components (u1,u2)
4) the plot of components (t1,u1) and the plot of components (t2,u2)