  We consider hydrodynamic scaling limits for a class of reversible interacting
particle systems, which includes the symmetric simple exclusion process and
certain zero-range processes. We study a (non-quadratic) microscopic action
functional for these systems. We analyse the behaviour of this functional in
the hydrodynamic limit and we establish conditions under which it converges to
the (quadratic) action functional of Macroscopic Fluctuation Theory. We discuss
the implications of these results for rigorous analysis of hydrodynamic limits.
