Cable Lengths - Bosch DCN Next Generation Installation And User Instructions Manual

DCN NG | Installation and User Instructions | Section 5 | System Installation

26.8 Cable lengths

26.8.1 Branch length
The total cable length between the CCU and the last
unit in any branch of the system must not exceed 250
m. This includes both unit and extension cables. See
figure 26.4 for an example.
26.8.2 Main branch
The total cable length between the CCU and the first
regenerative tap-off socket must not exceed 100 m. This
includes both unit and extension cables. See figure 26.4
for an example.
85
80
75 81
70
76
65
70
60 65
55
60
50 54
45
49
40 43
35
38
30
32
25 27
20
21
15
16
10 11
5
0 20
figure 26.3: Cable correction graph
Bosch Security Systems | 2004-03 | 9922 141 70521en
84
78
72 80
66 73 82
66
60 75
54 60 67
48 53 60
42 46 52
36 40 45
30 33 37
24 26 30
18 20 22
12 13 15
6 6 6 7
40 60 80
26.8.3 Power correction
The power available from an DCN socket is not only
influenced by the type and number of units connected
to the socket (see sections 26.5.2 and 26.5.3), but also by
the sum of the lengths of the extension cables connected
to the socket. Using the cable correction graph (see
figure 26.3), it is possible to correct the available power
for extension cable length. For each DCN socket:
1 Use the power consumption table (see table 26.1) to
calculate the amount of power consumed by the
units connected to the socket.
2 Calculate the total length of extension cable
connected to the socket.
3 Locate the value obtained in step 1 on the Y axis of
the graph (see figure 26.3) and the value obtained in
step 2 on the X axis. Using standard graph reading
procedures, join the two together to obtain the power
consumption corrected for extension cable length.
These are shown within the squares.
85
83
77
73 80
68
64 70 76
60
65
51 55 60
42 46 50 54
34 36 40 43
25 27 30 32
17 18 20 21
8 9 10 11
100 120 140 160
84
72 80
66 75
60 85
60
68
48 53
51
36 40 45
34
24 26 30
12 13 15 17
180 200 220 240 250
Extension cable (m)
en | 137
73
55
36
18
X