Bosch FPA‑5000 System Information page 32

32 en | Planning
Topologies in LSN improved with manual address setting (T-tap)
Loop
2 stubs with
branches
Tab. 3.4: Topologies in LSN improved with manual address setting (T-tap)
Loop topology
Each LSN element provides a built-in isolator between the b1 and b2 connectors. The current
flows through the LSN element between b1 and b2. With the return of the current to the LSN
module the loop is formed. In normal operation, an LSN loop is powered alternatingly from
one or the other side (LSN1/LSN2) of the loop, and direction of the current flow changes each
10 seconds.
Stub topology
Each LSN element provides a built-in isolator between the b1 and b2 connectors. The current
flows through the LSN element between b1 and b2. Therefore, the last element of the stub
has only incoming but no outgoing cable. Unlike for the loop topology, the direction of the
current flow remains the same.
T-tap topology
In a T-tap topology one or several branches exist anywhere along the LSN line.
Notice!
- From LSN module software version 1.0.35 onward, you can operate LSN improved elements
and LSN classic elements in combination in a loop or in a stub.
- If an LSN classic element is present, only 127 elements can be used in the loop.
- T-tap topologies are only possible if only LSN improved elements are used. As soon as an
LSN classic device is in a loop or stub, T-taps are no longer possible.
Notice!
In case of a bus fault, on stubs and branches no alternative way exists to reach an LSN
element. Since in a loop topology each element can be reached on an alternative way for
failure handling, prefer the loop topology.
Consider that regional authorities may require an upper limit to the number of elements that
can be lost due to a single fault.
07.2020 | 12.0 | F.01U.028.089
LSN 0300 A
LSN 0300 A
LSN 1500 A
LSN 1500 A
Stub
LSN 0300 A
LSN 1500 A
Loop with branches
System Information
LSN 0300 A
LSN 0300 A
LSN 1500 A
LSN 1500 A
Loop with one-
element branches
Modular fire panel
Bosch Sicherheitssysteme GmbH