Siemens FS720 - Cable Length and Cable Resistance

Installing, exchanging and connecting modules
Remote EVAC
-
NL and EVAC
-
NL m
imic display driver
7
228 | 248
Building Technologies
A6V10210390_m_en_
--
Fire Safety
2018
-
08
-
29
7.32.4 Cable length and cable resistance
If using a remote EVAC-NL indicator and the EVAC mimic display driver, the length
of the power supply cable is limited if the component is supplied internally via the
periphery board.
The diagram below can be used to determine the maximum cable lengths for both
cases.
The following cable is specified for the power supply:
● No shielding
● Twisted pair cable
● With at least 10 twists.
Please refer to the data for the corresponding component for the maximum RS485
interface cable length.
Figure 137: Diagram for calculating the max. cable resistance
1 Max. cable resistance R' for EVAC-NL mimic display driver
2 Max. cable resistance R' for remote EVAC-NL indicator
3 Max. current for remote EVAC-NL indicator
4 Max. current for EVAC-NL mimic display driver
x10 zones
R
'
c
a
b
l
e
[
O
h
m
]
C
u
r
r
e
n
t
[
A
]
2
3
4
1
1
2
3
4
5
6
7
8
9
10
0
20
40
60
80
100
120
0.0
0.3
0.6
0.9
1.2
1.5
1.8