Tyco MX4428 - Manual (Page 42)

MX4428 MXP Engineering / Technical Manual Document: LT0273
Device Information and Programming
Page 3-26 24 March 2006 Issue 1.5
3.12 5BI ISOLATOR BASE
3.12.1 GENERAL
The 5BI base is designed for isolating short circuited sections of the analog loop. For
instance it can be used where the loop wiring crosses zone boundaries to prevent a short
circuit from affecting more than one zone. When isolator bases are used, it is strongly
recommended that two additional isolator bases (possibly with no detectors inserted) be
installed at the start and end of the loop, close to the MXP.
Isolator bases may also be used to join multiple lines together in a single star arrangement,
for example when a number of conventionally wired zones are being converted to MX and a
loop cannot be wired.
Refer to section 4.1 for more details on the analog loop configuration.
There is a limit to the number of other devices which may be connected on the section of
cable between isolator bases. Calculate the sum of the “IB Units” from Table 3-2 for each
section of cable. The sum for each section must not exceed 100.
A section of cable is the portion between isolator bases or between an isolator base and the
MXP, or if a star configuration or tee is being used, between an isolator base and the end of
the cable.
3.12.2 SPECIFICATIONS
Line Connections IN M(–), L1(+)
Line Connections OUT L2(–), L1(+)
Remote LED Connection R(–), L1(+)
Supply Voltage 20Vdc - 40Vdc
Supply Current 80uA (typical quiescent)
Dimensions 110mm (diameter) x 22mm (excluding detector)
Weight 80g
3.12.3 WIRING
Figure 3.2 shows wiring for an 5BI, including connection of an external remote indicator.
Note that a common remote indicator may not be wired to a set of bases which are on
different sides of an isolator base.