  We introduce a technique for reachability analysis of Time-Basic (TB) Petri
nets, a powerful formalism for real- time systems where time constraints are
expressed as intervals, representing possible transition firing times, whose
bounds are functions of marking's time description. The technique consists of
building a symbolic reachability graph relying on a sort of time coverage, and
overcomes the limitations of the only available analyzer for TB nets, based in
turn on a time-bounded inspection of a (possibly infinite) reachability-tree.
The graph construction algorithm has been automated by a tool-set, briefly
described in the paper together with its main functionality and analysis
capability. A running example is used throughout the paper to sketch the
symbolic graph construction. A use case describing a small real system - that
the running example is an excerpt from - has been employed to benchmark the
technique and the tool-set. The main outcome of this test are also presented in
the paper. Ongoing work, in the perspective of integrating with a
model-checking engine, is shortly discussed.
