The system clingo[DL] provides a seamless way to integrate a subset of the theory of linear constraints, namely difference logic, into ASP. It deals with constraints of the form x-y<=k, where x and y are integer variables and k is an integer constant. Despite its restriction, difference logic can be used to naturally encode timing related problems, e.g., scheduling or timetabling, and provides the additional advantage of being solvable in polynomial time. Syntactically, a difference constraint x-y<=k is represented by a difference constraint atom of the form &diff {x-y} <= k.