Bosch Appliances 420 Radio User Manual


 
Fire Alarm Systems | FLM‑I 420‑S Short Circuit Isolator
The Short Circuit Isolator isolates alarm zones in which a
short circuit has occurred. This means the functionality of
the remainder of the network remains preserved.
System Overview
b1+ a- b2+ N/A N/A N/A
LSN
9 1
6 4
7 3
8 2
0
5
8 2
0
5
6 4
9 1
7 3
CL 1
2
0
Description Connector
b1+ / a- / b2+ LSN
N/A (3 x) free terminals, e.g. for looping through ext. auxiliary volt-
age and for shielding
Functions
Features of improved LSN
The interface modules in the 420 series offer all the
features of improved LSN technology:
Flexible network structures including T‑tapping
without additional elements
Up to 254 LSN-improved elements per loop or stub
line
Unshielded cable can be used
Address switch (rotary switch)
The address of the Short Circuit Isolator is set using the
rotary switches.
The following settings are possible:
0 0 0 Loop/stub in LSN mode improved version with automatic
addressing (T-tap system not possible)
0 0 1 - 254 Loop/stub/T-tap system in LSN mode improved version
with manual addressing
CL 0 0 Loop/stub in classic LSN mode
Configuration
The Short Circuit Isolator isolates alarm zones in which a
short circuit has occurred. The following illustrations
show typical configurations of the isolator module.
FLM‑I 420‑S Short Circuit Isolator
Rotary switch for automatic and manual address
setting
Preservation of LSN loop functions in the event of a
short-circuit by two integrated isolators
Power supply via LSN
Three free screw terminals
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