  Watson-Crick (WK) finite automata are working on a Watson-Crick tape, that
is, on a DNA molecule. Therefore, it has two reading heads. While in
traditional WK automata both heads read the whole input in the same physical
direction, in 5'->3' WK automata the heads start from the two extremes and read
the input in opposite direction. In sensing 5'->3' WK automata the process on
the input is finished when the heads meet. Since the heads of a WK automaton
may read longer strings in a transition, in previous models a so-called sensing
parameter took care for the proper meeting of the heads (not allowing to read
the same positions of the input in the last step). In this paper, a new model
is investigated, which works without the sensing parameter (it is done by an
appropriate change of the concept of configuration). Consequently, the accepted
language classes of the variants are also changed. Various hierarchy results
are proven in the paper.
