Maximum Current Connection Factor Reserve - Siemens FS20 Planning Manual

7.1.9 Maximum current connection factor reserve

7.1.9.1 Procedure by means of an example
Device
Neural fire detector
Input/output module
Alarm sounder
Sounder base
↑ Floor repeater terminal
without external supply
Total
Building Technologies
Fire Safety
This chapter describes how to verify the possible reserve of the ↑ maximum
current connection factor (MK_res) for one line by means of an example. This is
done with the aid of diagrams for the different line cards.
Assumption
The following parameters have already been determined.
Parameters
↑ Line card
Topology
Relevant cable length for resistance
Relevant cable length for capacitance
Cable type
Table 21: Exemplary parameters for a detector line
The devices in the following table shall be operated on the loop
Type Number AK
FDOOT221 14
FDCIO222 2
FDS221 1
FDSB291 1
FT2010 1
Table 22: Connection factors for exemplary line calculation
Calculations
The following values can be determined based on the above details:
● Cable resistance (R)
R = L x R' = 1.2 km * 125 ohm/km = 150 ohm
Cable
● Cable capacitance (Cs)
Cs = L x Cs' = 1.5 km * 70 nF/km = 105 nF
Cable_total
Cs must be within the limit value.
● Address connection factor: AK = 18
● ↑ Quiescent current connection factor: RK = 41.5
The quiescent current connection factor is needed later on to calculate the
hardware's operating current.
● ↑ Maximum current connection factor: MK = 200
Planning an FDnet detector line
Value
Integrated line card with ↑ loop
extension (FDnet)
4 loops
1200 m
1500 m
● G51 extra-low-voltage cable
● x 0.6 (CH), unshielded
● R' = 125 Ohm
● Cs' = 70 nF
ΣAK RK
1 14 1
1 2 3
1 1 1
0 0 0.5
1 1 20
18
Planning detector lines
ΣRK MK ΣMK
14 1 14
6 3 6
1 15 15
0.5 5 5
20 160 160
41.5 200
79 | 242
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2015-12-15
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