The behaviour of PEPA models with large numbers of components can be approximated in a continuous fashion by a set of coupled ordinary differential equations (ODEs). Timed continuous Petri nets can be used to approximate behaviour via ODEs in a scenario of many servers. These two formalisms are compared, a translation from a PEPA model to a Petri net is given, and it is shown that the ODEs obtained in each case are the same. Different server semantics for Petri nets are also considered.