Using your sentence as the starting point:
On the Java end (no hyphen), a break in the connection is signaled by an exception when reading from or writing to the Profinet bus.
Or, rephrasing it slightly,
On the Java side, when reading from or writing to the PROFINET bus, a break in the connection is signaled by an exception.
Of the suggested changes, replacement of "acknowledged" by "signaled" (or by "announced", or "flagged") is the most important.