  Reversible computing is a concept reflecting physical reversibility. Until
now several reversible systems have been investigated. In a series of papers
Kenichi Morita defines the rotary element RE, that is a reversible logic
element. By reversibility, he understands that 'every computation process can
be traced backward uniquely from the end to the start. In other words, they are
backward deterministic systems'. He shows that any reversible Turing machine
can be realized as a circuit composed of RE's only. Our purpose in this paper
is to use the asynchronous systems theory and the real time for the modeling of
the ideal rotary element
