Fire Detection System Planning Guide

Bus systems
15
Siemens Building Technologies 007836_a_en_--.doc
Fire & Security Products 03.2004
6.1 Bus overview
Features C-Bus I-Bus SynoLOOP SynoLINE600 LON-Bus Data Bus
Field of applica-
tion
Local system bus Inside control unit
For addressable
detectors
For collective
detectors
Local data bus
for floor indicator
panels
Local data bus
parallel ind.
panel, synoptic
panel or relay
Speed of trans-
mission
57kBaud 1000kBaud 2 messages/sec
(Direct current
signal)
78kBaud SPI-Bus 2KHz
Length of line
Max. 1000m
(G51 ∅ 0,8: 1400m)
Max. 3m (only
inside cabinet)
Max. 150Ω/300nF
See chapter 16
Max.
150/250Ω/4µF
See chapter 16
Max. 500m as
free topology
Max. 1000m as
stub line
Max. 1000m
Number of users
connected or
addresses
… 16
C-Bus devices
… 16
I-Bus modules
… 128
D-Bus devices
1 address
(Max. 25 detec-
tors)
… 32
LON-Bus de-
vices
… 24
Max. 8 addresses
Number of wires 2
(+3 wires for emer-
gency operation)
26 2 2 2
6
(+3 wires supply)
Type of cable
Twisted 1) Flat cable
Twisted
(Un-twisted per-
missible)
Twisted
(Un-twisted
permissible)
Twisted Twisted
Loop line
✔
–
✔
– – –
T-branch
– – – –
✔
(See chapter 18)
–
Short-circuit proof Yes
Each user con-
nected with line
separator
–
Yes
Each user con-
nected with line
separator
No No Yes
Network structure
Master/master Master/slave Master/slave Master/slave Master/slave Master/slave
Scanning
Event-controlled,
presence monitoring
Cyclic,
Event controlled
Cyclic
- typ. all 64s
- Interrupt on
alarm
–
Event-controlled,
presence moni-
toring
(All 60s)
Cyclic
- typ. all 250ms
Principle
Serial Bus
- Cerberus protocol
- Collision detection
- Manchester coding
C-Bus
- Cerberus protocol
- SPI/Motorola
Sensor/actor-Bus
- Cerberus proto-
col 'K31'
- Serial 8bit
- Start-up: daisy-
chain
Conventional
- Current gain
principle
- Voltage levels
Network
- Echelon Chip
(LON protocol)
- Cerberus
specific telegram
Serial bus
- Cerberus proto-
col
1 Calibrated according to cable impedance: 50Ω (MICC) / 110Ω (G51, ø
0.8mm, not shielded)
6.2 Modifying the impedance of the various C-Bus cables
C-Bus standard cables have a characteristic impedance of 110Ω. The driver and
end-of-line resistors are soldered to solder lugs and can be adapted accordingly
with other characteristic impedances (see diagram chapter 6.2.1).
1. Explanation
A cable must be terminated with resistors. The resistance value must correspond
to the impedance of the cable. Each C-Bus user has four end-of-line resistors
(Ri). In addition two driver resistors (Rd) are integrated on the p.c.b. In order that
the resistors can be exchanged easily they are all soldered to solder lugs.
C-Bus p.c.b. Ri Rd
B3Q700 R31 ... R34 R49, R50
E3H020 R173, R174, R177, R178 R180, R183
The driver resistors specify the current on the C-Bus. In order that the signal on the
C-Bus always has the same amplitude (1.35Vpp), the following correlation is valid:
Rd = Ri x 3,65 (45Ω < Ri < 200Ω)