16
Morley-IAS
996-203-000-2, Rev. 02
Table 2 - Maximum Loop Lengths
-
Cable runs in excess of 2km (6400’) are not recommended. Otherwise, cable capacitance (Max.
0.5
μ
F per loop) and inductance may start to interfere with data transmission. Refer to the
manufacturers’ quoted figures for maximum cable capacitance.
3.4.5.3
Loop Wiring Installation
·-
The SLC (detector) circuits should be installed as loops with or without isolator modules. The wiring
details are as described below.
EN54-2: 12.5.2
Maximum of 32
sensors/ MCPs
between isolators.
EN54
!
For best results and system integrity:
The detection loop circuit should be wired as a loop with
short circuit isolators. This will allow the system to still
function, even if a section of the cable becomes short
circuited. It is recommended that short circuit isolators
be fitted to the detection loop to prevent an external short
circuit from removing more than 32 addressable points
from the system.
-
The detection loop connections are made
on terminal blocks at the top of the base
card. The diagrams opposite show the
location of the terminal blocks and typical
wiring connections.
-
The DXc1 variant has only one connector
available – i.e. Loop 1. The DXc2 and DXc4
have four connectors available – only Loops
1 and 2 are used on the DXc2.
-
Form the loop by taking wires from the
positive and negative terminals, at one side
of the connector on the base card – see
opposite.
-
Proceed with installing wiring, around the
loop, connecting all devices – see below.
-
Return the wiring to the positive and
negative terminals at the other side of the
connector on the base card.
-
Ensure that all devices connected to the
loop are correctly oriented for positive and
negative connections.
-
Refer to the detector manufacturers’ data
sheet supplied with the signalling device.
Figure 12 - SLC Connections
Maximum Loop Length
MICC
18 AWG
16 AWG
14 AWG
1.5mm
2 km
1 km
1.5 km
2 km
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