Siemens Synco 700 Series Operator's manual

Edition 2.0
CE1P3127en
30.08.2007 Building Technologies
HVAC Products
3127Z01
Synco™
Communication via the KNX bus
For Synco 700, 900 and RXB/RXL
Basic Documentation

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Siemens Schweiz AG
Building Technologies Group
International Headquarters
HVAC Products
Gubelstrasse 22
CH-6301 Zug
Tel. [phone]
Fax [phone]
www.siemens.com/buildin
g
technolo
g
ies
© 2003-2007 Siemens Switzerland Ltd
Subject to change

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Contents
1KNX (Konnex) and Synco........................................................................7
1.1 General overview.......................................................................................7
1.1.1 Definition of terms......................................................................................8
1.2 Synco 700, 900, RXB/RXL range ............................................................10
1.2.1 Collective terms for the device types.......................................................11
1.2.2 Product markings on Synco bus devices.................................................11
1.3 The KNX network.....................................................................................12
1.3.1 Full-scale KNX network............................................................................12
1.3.2 Network address......................................................................................13
1.3.3 Device address ........................................................................................14
1.4 Area/line couplers and IP router ..............................................................15
2Engineering notes..................................................................................17
2.1 Designing the network .............................................................................17
2.1.1 Design engineering procedure.................................................................17
2.1.2 Number of bus devices per line, area and network .................................18
2.1.3 Bus load number E...................................................................................18
2.2 Bus power supply.....................................................................................19
2.2.1 Decentral bus power supply.....................................................................19
2.2.2 Power consumption of the bus devices ...................................................20
2.2.3 Central bus power supply ........................................................................21
2.3 Bus topologies..........................................................................................22
2.3.1 Distances and cable lengths....................................................................23
3Commissioning notes ...........................................................................25
3.1 Points to check prior to commissioning....................................................25
3.2 Commissioning with the RMZ operator units...........................................26
3.2.1 Starting commissioning, plant mode "Off"................................................26
3.2.2 Terminating commissioning, plant mode "Auto".......................................28
4Device address and device name.........................................................29
4.1 RM… controllers ......................................................................................29
4.1.1 Reading the area, line and device address .............................................29
4.1.2 Assigning device names ..........................................................................30
4.2 Setting device address with RMZ790 and RMZ791 operator units.........32
5Device addresses via ACS....................................................................33
5.1 Service tool OCI700.1 and ACS7… software ..........................................33
5.1.1 Overview..................................................................................................33
5.1.2 New plant.................................................................................................34
5.1.3 Establishing a connection ........................................................................35
5.1.4 Edit device list..........................................................................................35

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5.1.5 Addressing devices with the OCI700.1 service tool.................................37
5.2 RM… controller device address...............................................................38
5.2.1 Assigning addresses manually.................................................................38
5.2.2 Assigning addresses automatically..........................................................39
5.2.3 Assigning addresses in programming mode............................................40
5.2.4 Addressing via the ID number..................................................................41
5.3 Device address for the OZW771.xx central communication units...........42
5.3.1 Other addressing options, OZW771.xx....................................................43
5.3.2 Restoring the factory settings, OZW771.xx .............................................43
5.4 Device address for the OZW775 central communication unit..................44
5.5 Device address for the QAX910 central apartment unit...........................45
5.6 Device address for the RXB/RXL room controllers..................................48
5.6.1 RXB/RXL device address with QAX34.3 room unit .................................49
5.7 Device address for the QAW740 room unit..............................................51
5.8 Device address for RMZ792 bus operator unit........................................53
5.9 Addressing the couplers...........................................................................56
5.9.1 Line couplers............................................................................................56
5.9.2 Area couplers...........................................................................................58
5.10 Addressing the IP router ..........................................................................59
5.10.1 KNX network address ..............................................................................59
6Basic communication settings.............................................................61
6.1 RM… controllers.......................................................................................61
6.1.1 Decentral bus power................................................................................61
6.1.2 Clock time operation ................................................................................61
6.1.3 Setting a time slave remotely...................................................................62
6.1.4 Remote reset of fault................................................................................64
6.2 Basic settings via ACS .............................................................................65
7Communication via zone addresses....................................................67
7.1 General notes on zones...........................................................................67
7.1.1 Synco zoning............................................................................................67
7.1.2 Communication of process values...........................................................68
7.1.3 Geographical zone (apartment) ...............................................................69
7.1.4 Default "----" in series B devices ..............................................................70
7.2 Zone addressing with the RMZ operator units.........................................72
7.2.1 RM… controllers.......................................................................................72
7.2.2 QAWZ740 room unit.................................................................................73
7.3 Addressing the zones with ACS...............................................................74
7.3.1 RM… controllers.......................................................................................74
7.3.2 RXB/RXL room controllers.......................................................................75
7.3.3 Zone addressing with the QAX34.3 room unit.........................................75

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8Large plants............................................................................................77
8.1 Engineering and commissioning..............................................................77
8.1.1 Network topologies...................................................................................78
8.1.2 IP router as a coupler to the IP network...................................................81
8.2 LTE filter table for couplers and IP routers...............................................84
8.2.1 Filter settings............................................................................................84
8.2.2 Predefined LTE filter table........................................................................85
8.2.3 Filtering, zone addresses, communication areas ....................................86
8.2.4 LTE telegrams via couplers and IP routers..............................................87
8.2.5 System time, alarms and remote time adjustments.................................89
8.3 Engineering of large plants......................................................................90
9Appendix.................................................................................................93
9.1 Faults and errors......................................................................................93
9.1.1 Bus fault status message.........................................................................93
9.1.2 Communication errors..............................................................................94
9.2 Heating / cooling changeover ..................................................................95
9.2.1 Changeover via digital input.....................................................................96
9.2.2 Changeover via analog input...................................................................97
9.2.3 Changeover based on calendar...............................................................98
9.2.4 H/C changeover relay and fault messages..............................................99
9.3 Room control combination .....................................................................100
9.3.1 Application examples.............................................................................100
9.4 Applications with zones..........................................................................104
9.4.1 Additional zones in the RXB/RXL room controller .................................105
9.5 Supply chains.........................................................................................106
9.5.1 Data exchange in LTE mode..................................................................108
9.6 Updating the process values..................................................................109
9.7 Lightning and overvoltage protection, EMC...........................................110
9.7.1 Lightning protection................................................................................110
9.7.2 Overvoltage protection...........................................................................113
9.7.3 Overvoltages in loops.............................................................................114
9.7.4 EMC protection management................................................................115

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HVAC Products KNX (Konnex) and Synco 30.08.2007
1 KNX (Konnex) and Synco
1.1 General overview
This document contains:
•Section 1 Introductory information about Synco and the KNX network
•Section 2 Notes on engineering
•Section 3 Notes on commissioning
•Sections 4 to 7 Device address, device name and addressing via ACS,
special features of KNX addressing and communication in LTE mode.
•Section 8 Designing "large plants"
•Section 9 Appendix with supplementary information of a general nature
This document contains specific information applicable to the European Tool Set
(ETS3) only. S-mode communications are not dealt with here.
The KNX Association has its headquarters in Brussels and is an organization or
association of manufacturers which maintains the KNX standard and develops it
further. The KNX Association supports the trend towards the "smart house", in
which the various building services including lighting and security systems all
communicate on the same network.
The aims and objectives of the KNXAssociation are as follows:
•To determine the range of functions for the devices installed in the network
•To promote interaction between products from a wide range of manufacturers
(interworking)
•To certify products that fulfill the KNX standards
•To facilitate the commissioning of equipment in KNX networks
•To open the KNX bus to communications providers and utilities companies
•To exploit various transfer media: bus (TP1), wireless (RF) and power line (PL)
The Synco devices are designed for HVAC applications and individual room control.
They are used in:
•Residential buildings
•Shops and offices
•Shopping centers and commercial buildings
•Schools and training centers
•Hotels and fitness, leisure and wellness centers
The KNX bus enables the Synco devices to communicate with each other, i.e. to
exchange process values and system data in LTE mode. Typical values and data
are:
•Outside air temperature to devices in the same "outside air temperature zone"
and room temperature to devices in the same "geographical zone"
(multiple use of sensor values)
•Heating and cooling demand signals from zone controllers to the devices in the
primary LTHW and CHW plant.
•DHW priority signals (e.g. while charging the DHW tank)
•Time synchronization (the time master synchronizes the time slaves)
•Remote indication of fault and error messages (e.g. sensor error)
About this document
Note
KNX Association
KNX and Synco

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1.1.1 Definition of terms
The KNX bus used with Synco is referred to as "KNX TP1". A full-scale KNX
network is a three-level structure consisting of one area line, from which 15 main
lines branch off. A further 15 lines can branch off from each main line. A network
consisting of main lines and lines requires area and line couplers. If no area and
line couplers are used, the network is restricted to one line.
Permissible bus topologies are tree, line and star topologies. These topologies can
be mixed as required. However, ring topologies are not allowed. The tree topology
has advantages over other topologies in cases where a large network has to be
created (refer to "Bus topologies" in the KNX bus data sheet, N3127).
The bus cable comprises two twisted conductors, CE+ (red) and CE– (black).
3127Z05
CE+
CE−
Unshielded bus cables are permitted for the KNX bus in conjunction with Synco
devices. Shielded bus cables are recommended, however, if high interference is
anticipated. For further details refer to data sheet N3127.
The KNX bus uses CSMA/CA(CSMA = Carrier Sense Multiple Access / CA=
Collision Avoidance) to access the bus. With this method of access every bus user
has equal data transmission rights. There is no communication master (in contrast
to the master/slave principle). The data is exchanged directly (peer-to-peer)
between bus users.
A collision avoidance strategy is required when several bus users attempt to send
a message on the bus at the same time (multiple access). One bus user is given
transmission priority, so that it can transmit its telegram fully and correctly. The
other bus users stop transmitting and repeat their message after a given delay.
The CSMA/CA method offers quick response times if the transmission capacity
(number of connected bus users and process events) is utilized within the
permitted limits.
LTE mode (LTE = Logical Tag Extended) is characterized by the assignment of
zone addresses (logical tags) to create communications bindings for the exchange
of process values. Devices with the same zone address exchange process values
with each other, one zone address being capable of transmitting the values of
many data points.
The zones are addressed during local commissioning with the RMZ790 or RMZ791
operator units, or in the case of remote operation, with a PC/laptop and the
ACS7… software.
KNX bus
Bus topologies
Bus cable
Bus access method
LTE mode
Zone addresses

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S-mode is characterized by the assignment of (logical) group addresses to
individual data points to create the communications bindings for the exchange of
process values. Devices bearing the same group address exchange process
values with each other.
The group addresses can be assigned to the group objects (S-mode data points)
with the ETS engineering and commissioning tool (ETS = Engineering Tool
Software).
For the various HVAC, lighting and security equipment and for integration into
higher-level building automation and control systems, selected data points of the
Synco devices can also communicate in S-mode.
"Data points" are also referred to as "communication objects".
Description
Ac Area coupler (see section 1.4)
DPSU Decentral Power Supply Unit (see section 2.2.1)
E-Mode Easy-Mode, LTE-mode is one of several "Easy Modes"
ETS Engineering Tool Software
HVAC Heating, Ventilation and Air Conditioning
IP Internet Protocol
Lc Line coupler (see section 1.4)
LTE-Mode Logical Tag Extended Mode, the Easy Mode used by Synco
KNX Communications standard (wired) TP1 (Twisted Pair)
PSU Power supply unit, (see section 2.2.3)
S-mode System mode, configuration / commissioning with ETS only
TP1 Twisted Pair 1, data transfer medium: bus
S-mode
Group addresses
Data points
Abbreviations

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1.2 Synco 700, 900, RXB/RXL range
The table below lists those devices in the Synco 700, 900 and RXB/RXL ranges
which have a TP1 (wired) KNX interface.
These devices have a network address and can communicate via the KNX bus in
LTE mode.
The table does not cover all the devices in the various ranges. For example, the
Synco 700 extension modules RMZ78x and the Synco 900 wireless components
are not included.
Equipment Types Data sheet
Universal controllers
for use in ventilation, air conditioning and chilled water systems
RMU Series B also for primary plant applications
in conjunction with individual room control
RMU710
RMU720
RMU730
RMU710B
RMU720B
RMU730B
N3144
N3150
Heating controllers
For boiler and heating circuit controls or primary controllers
Additionally: RMH Series B also for district heating plant
RMH760
RMH760B
N3131
N3133
Boiler sequence controller
for multiple boiler systems with up to 6 boilers
RMK770
N3132
Central control unit
For individual room control with RXB/RXL room controllers
RMB795
N3121
Switching and monitoring device
For HVAC and chilled water applications
RMS705
N3123
Bus operator unit
Access via KNX to Synco 700 devices and RXB/RXL room controllers
RMZ792
N3113
Room unit
With setpoint adjuster and mode and timer buttons
QAW740
N1633
Central communication units
For remote operation and monitoring of Synco devices in KNX networks
Central communication units for up to 4, 10 or 64 Synco devices
Central communication unit for up to 150 Synco devices
OZW771
OZW775
N3117
N5663
Central apartment unit
For management of one apartment Heating/cooling/ventilation, control of
lighting and blinds, door and window monitoring
QAX910
N2707
Room controllers
For fan-coil units with 3-speed fan control
For fan-coil units with 3-speed fan control and electric heating coil
For fan-coil units with 3-speed fan control
For fan-coil units with 3-speed fan control and electric heating coil
For chilled ceilings and radiators
For chilled ceilings and radiators
RXB21.1
RXB22.1
RXL21.1
RXL22.1
RXB24.1
RXL24.1
N3873
N3877
N3874
N3878
ACS7… software and service-interface
For Synco device commissioning and diagnostics
OCI700.1
N5655
The RMZ790 and RMZ791 operator units are not bus devices. However they can
be used to commission the Synco 700 type RM… controllers (e.g. to set the device
address, see section 4.2).
Operator units
Plug-in unit for Synco 700 controllers
Also suitable for mounting away from controller, e.g. on control panel door
RMZ790
RMZ791
N3111
N3112
The devices in the Synco 100 and Synco 200 ranges are non-communicating and
are not dealt with in this document.
Introduction
Synco 700
Synco 900 (Synco living)
Synco RXB/RXL
Service tool
RMZ790 and RMZ791
operator units
Synco 100, Synco 200

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1.2.1 Collective terms for the device types
In this document, the devices on in the table on the previous page may be referred
to collectively as follows.
The term "Synco 700 type RM… controllers", or "RM… controllers" for short, refers
collectively to the following types:
•Universal controllers RMU710, RMU720, RMU730
RMU710B, RMU720B, RMU730B
•Heating controllers RMH760, RMH760B
•Boiler sequence controllers RMK770
•Central control units RMB795
•Switching and monitoring device RMS705
The term "RXB/RXL room controllers" or "RX… room controllers" refers collectively
to the following types:
•Room controllers RXB21.1, RXB22.1
•Room controllers RXL21.1, RXL22.1
The term "OZW77x central communication units" refers collectively to the following
types:
•Central communication units OZW771.xx (where xx = 4, 10 or 64)
•Central communication unit OZW775
The term "Synco bus devices" refers collectively to the following types:
•Synco 700 controllers RM…
•Room controllers RX…
•Room unit QAW740
•Bus operator unit RMZ792
•Central communication units OZW77x
•Synco 900 central apartment unit QAX910
"Bus devices" include the Synco bus devices (see above) and devices from third-
party manufacturers. Bus units use a KNX network address.
1.2.2 Product markings on Synco bus devices
The Synco bus devices are labeled with product markings with the following
meanings:
KNX logo Devices with this logo are certified by Konnex
KNX transmission medium TP1 stands for Twisted Pair 1(1 pair of twisted wires)
KNX configuration mode EE stands for Easy (mode), Logical Tag Extended
Synco 700 type
RM…controllers
RXB/RXL room controllers
OZW77x central
communication units
Synco bus devices
Bus devices
TP1
EE

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1.3 The KNX network
1.3.1 Full-scale KNX network
A full Konnex network is structured on three levels. It consists of:
•Area line 0 ÆArea 0 (backbone line)
•Main lines 1...15 ÆAreas 1…15
•Lines 1.1...15.15
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
Linie 1 Linie 2 Linie 3
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
Linie 1 Linie 2 Linie 3
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
1
2
3
64
Ac
1.0.0
Lc
1.1.0 Lc 1.2.0 Lc 1.3.0 Lc 1.15.0
Area 1
Line 1 Line 2 Line 3 Line 15
Main line 1
Lc
0.1.0 Lc 0.2.0
Line 1 Line 2
Ac
2.0.0
Lc
2.1.0 Lc 2.2.0 Lc 2.3.0
Area 2
Line 15
Main line 2
Ac
3.0.0
Lc
3.1.0 Lc 3.2.0 Lc 3.3.0 Lc 3.15.0
Area 3
Line 15
Main line 3
Ac
15.0.0
Lc
15.1.0 Lc 15.2.0 Lc 15.3.0
Area 15
Line1 Line 2 Line 3
Main line 15
Arealine0(ba
c
kboneline
)
3127Z10en
Lc
2.15.0
The arrangement of the bus devices in the 3-level KNX network structure, with the
Synco bus devices factory set withArea/Line address 0.2 corresponds to the gray
shaded area in the illustration above.
KNX network,
three-level structure
Note

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The area line is the backbone of the network. The subnetwork address (area line)
is 0.0 (zero.zero). 15 area couplers (Ac) can be connected to the area line, in
addition to bus devices (not shown), whose number is determined by subtracting
the number of area couplers from 64.
15 main lines can branch off from area line 0 by means of area couplers. The area
couplers used to establish the main lines have physical addresses from 1.0.0 to
15.0.0. Each main line can accommodate 15 line couplers (Lc), in addition to bus
devices (not shown) whose number is determined by subtracting the number of line
couplers from 64.
15 lines can branch off from each main line via line coupler. The line couplers used
to establish the lines from main line 1 have physical addresses from 1.1.0 to 1.15.0.
Line couplers from main line 15 have physical addresses from 15.1.0 to 15.15.0.
1.3.2 Network address
The network address for a full-scale KNX network consists of the area, line and
device address. It reflects the exact position of a bus device in the overall network
and is unique within the network.
Syntax: Area.Line.Device
Area 0 Factory-set for Synco bus devices = 0 (backbone)
Area 1...15
Line 1...15 Factory-set for Synco bus devices = 2
Device 1...255 Factory-set for Synco bus devices = 255
except OZW775 central communication unit = 150
The Synco bus devices are factory-set with the KNX-defined area and line
address 0.2.
The "individual address" (a term from the KNX world) consists of the address
components area, line and device, and corresponds to the network address
already defined.
The "physical address" is another term (translated literally from the German) for the
"individual address".
In KNX terms, a subnetwork is the same as a line. Hence, the subnetwork address
consists of the address components "area" and "line".
Area line 0
Main lines
Lines
Network address
Syntax of the network
address
A
rea and line address
Individual address
Physical address
Subnetwork,
Subnetwork address

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1.3.3 Device address
As described above, the network address consists of a combination of the area,
line and device address, for example 0.2.10, where 0 stands for the area, 2 for the
line and 10 for the device address.
3127Z31
0.2.254
0.2.1 0.2.2 0.2.10
Konnex TP1
0.2.150 0.2.252
0.2.11 0.2.20
The addressing of the devices must be planned at the design engineering stage.
Note the following points when assigning addresses:
•Each device address may be allocated only once within an area and a line.
Device addresses in the range 1 to 251 must be used for the maximum 64 bus
devices on a line (the same applies on a main line). Addresses 0, 150, 252, 254
and 255 are reserved for the following:
0 is used in each area or each line for the area or line coupler respectively.
150 is the factory-set device address for the OZW775 central communication unit
(device address 150 can be modified)
252 is used to connect the RMZ792 bus operator unit, i.e. the bus operator unit
uses this address if it is free, otherwise it starts at 252 and looks for the next
lower unused address.
254 is used to connect theACS operator station (PC/Laptop with ACS7…
software) i.e. the OCI700.1 service tool uses this address if it is free,
otherwise it starts at 254 and looks for the next lower unused address.
255 is the factory-set device address of the Synco bus devices (see the notes
below).
The factory-set address 255 in the Synco bus devices prevents communication
problems in the commissioning phase. This is because devices with this address
do not send any data. However they can be controlled manually, and can receive
the new device address setting, for example.
The device addresses of the Synco 700 type RM… controllers can be set with the
RMZ790 and RMZ791 operator units (see section 4.2) or with the ACS7… software
(service tool OCI700.1, see section 5.2).
Remember not to use device addresses 150, 252 and 254 when addressing the
bus devices.
Device identification
Device addressing
Notes

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1.4 Area/line couplers and IP router
Complex networks covering large areas may require area and line couplers for two
main reasons.
•When the KNX network comprises more than 64 bus devices
•When the network would exceed the permissible limits without couplers
A network which uses area and line couplers makes it possible to create
"communication islands" with the aim of restricting data traffic across areas or lines
to a minimum. The couplers link the "communication islands" on the basis of the
network layer (the router function of Layer 3 of the OSI reference model).
The recommended area/line couplers are supplied by Siemens, ordering code:
•5WG1 140-1AB13, short code N140/13
bus connected to main line and line via bus terminals
For further information refer to the product description and description of functions
(enclosed with the device) or consult:
www.automation.siemens.com/et/gamma/
For large plants, Siemens area/line couplers from version R2 should be used
(these are stamped "R2") as only these couplers contain the LTE filter table (see
section 8.2).
IP1) routers are required when a KNX network needs to be connected to an IP
network.
As a device, the IP router is not technically the same as the area/line couplers.
Instead of establishing a link within KNX, a "KNX-IP network" link is created,
whereby the IP router connects a KNX area or a KNX line to an IP network.
1) IP = Internet Protocol: Network protocol for data traffic, routing and, in the case of internetworking,
for global, addressing.
The recommended IP router is supplied by Siemens, Order No.
•5WG1 146-1AB01, short code N146
Bus connected via bus terminals, IP network connected via RJ45 socket
For further information refer to the product description and description of functions
(enclosed with the device) or under:
www.automation.siemens.com/et/gamma/
For large plants, Siemens IP routers from Version R4 should be used (these are
stamped "R4") as only these IP routers contain the LTE filter table (see section 8.2).
Use of couplers
Siemens
area/line couplers
Note
Use of IP routers
Siemens IP router
Note

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2 Engineering notes
2.1 Designing the network
2.1.1 Design engineering procedure
For design engineering refer also to the information in data sheet N3127.
Step Activity Objective
1 Assess the situation •Accurate site plan with location
of the buildings and layout of
rooms
•Overview of hydraulic system
2 Work out proposed solutions and
establish how to implement them.
•Clear project definition
3 Include plans for possible
expansion zones for extensions
•Advance planning of the scope
for expansion of the plant
4 Determine device types and
quantity
•Table of device types
•Number of devices per line and
area, within the permitted limits
5 Define the installation of the
devices in accordance with their
technical functions
•Entry on plant diagram
•List of applications
6 Define cable routing and cable
lengths
•Entry on plant diagram
•Network size within permitted
limits
7 Determine type of bus power
supply
•Decentral bus power
•Central bus power supply
8 Check limits •Number of bus devices per line
and area
•Size of network
•Adequate bus power (with
reserve for later expansion)
9 Create network structure and
wiring diagram
•Complete installation and
commissioning documents
When structuring a network, special attention should be paid to certain criteria:
•The number of bus devices in a line, in an area and in the network
•The type of bus power supply in relation to the number and properties of the bus
devices
•The total length of all the bus cables in one line and in the network
•The distances between the bus devices
•The distance between the bus devices and the nearest bus power supply
Refer to the special notes in section 8 on design engineering for large plants.
Account must also be taken of special criteria in relation to lightning and
overvoltage protection and EMC. For details refer to the discussion in section 9.7.
Design engineering
flow chart
Project data
Devices, bus devices
Network
Special criteria
Large plants
Lightning and overvoltage
protection, and EMC

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2.1.2 Number of bus devices per line, area and network
Up to 64 bus devices can be installed on one line (including a main line and area
line 0). There are no restrictions relating to the type mix.
The Synco 700 type RMZ78x expansion modules, the RMZ790 and RMZ791
operator units and the room units connected (via PPS2) to the RXB/RXL room
controllers do not have a KNX interface and can be omitted from the design total.
In installations incorporating Synco bus devices (plus the OCI700.1 service tool, if
connected) and third-party devices, the number of Synco bus devices is reduced in
accordance with the number of third-party devices.
Based on 64 bus devices per line and 15 lines per area, up to 960 bus devices can
be installed in an area. The network addresses for Area 1 are:
•Area coupler 1.0.0
•Line coupler 1.1.0…1.15.0
•Bus devices 1.1.1…1.15.254
With KNX TP1 only 64 bus devices are permitted in device address range 1…254.
Theoretically, a total of 16,320 bus devices could be installed in a full KNX TP1
(wired) network. In practice the number is approximately 12,000 bus devices.
Based on 960 bus devices per area, and a full-scale network comprising 15 areas,
up to 14,400 bus devices can be installed in one network.
64 bus devices can be connected to each of the 15 main lines, giving a further 960
bus devices in addition to the 14,400 calculated above, which makes a total of
15,360 bus devices.
Another 64 bus devices can be installed in each of the 15 lines branching off from
area line 0, now giving a total of 15,260 bus devices. Normally, however, no line
couplers are installed in area line 0.
Note: The preset addresses, area address 0 and line address 2 relate to a
"notional line 2" branching from area line 0. The network addresses for this line are
0.2.1 to 0.2.254.
The term "notional line 2" indicates that there is no need to install a line coupler
0.2.0. See the illustration in section 1.3, Full-scale KNX network.
2.1.3 Bus load number E
The bus load number E (short, E-number) applies to the average data traffic of a
device on the bus.
The bus load number does not have to be calculated for a line containing the
permitted 64 bus devices (the total of bus load number is less than 300).
The bus load number E of a device is specified in the relevant data sheet.
64 bus devices
on one line
Notes
960 bus devices
in one area
Note
16,320 bus devices
in a network
Main lines 1…15
A
rea line 0
Notional Line 2
Data traffic of a device

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2.2 Bus power supply
2.2.1 Decentral bus power supply
A bus power supply is always required for bus communications. There are two
options:
•Decentral bus power supply DPSU = Decentral Power Supply Unit
•Central bus power supply PSU = Power Supply Unit
In any one line (including a main line) either the DPSU or PSU may be used.
The following devices are delivered factory-set with "Decentral bus power supply =
On" and supply power to the bus:
•Synco 700 type RM…controllers DC 29 V, 25 mA
•OZW775 central communication unit DC 29 V, 25 mA
•QAX910 central apartment unit See the warning note below, marked
Since the devices, which are factory-set to "Decentral bus power supply = On", are
distributed on the bus, they are referred to as "Decentral bus power supply, DPSU".
Devices with the setting "Decentral bus power supply = On" must not be installed
on the same line as third-party devices. In such cases, the devices must be set to
"Decentral bus power supply = Off" and a power supply unit must be installed (see
next section "Central bus power supply").
In devices with a bus power supply, the bus power section is electrically isolated
from the KNX bus.
In addition to its own intrinsic consumption, the QAX910 central apartment unit
when set to "Bus power supply = On" delivers the bus power for one OZW771
central communication unit or for the OCI700 service interface.
If other devices are installed on the same line, the central apartment unit must be
set to "Bus power supply = Off". In this case, the bus power must be supplied by
setting other devices such as the RM… controllers to "Decentral bus power supply
= Off", or by installing a power supply unit.
Devices without a bus power supply:
•QAW740 room unit
•RXB/RXL room controllers
•RMZ792 bus operator unit
•OZW771.xx central communication units
•OCI700 service interface
•Area/line couplers and IP router
Devices without a bus power supply require devices on the same line with a DPSU
or a power supply unit, PSU.
Introduction
Note
Devices with bus power
Notes
Caution!
Devices without a
bus power supply
Note

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The rule is: One device with a DPSU can operate two devices without a bus power
supply plus the OCI700 service interface and OZW771 central communication unit.
Per line, the rule is:
1 device with a DPSU + 2 devices with no bus power supply + OCI700 + OZW771
up to a maximum of
8 devices with a DPSU + 16 devices with no bus power + OCI700 + OZW771
An RM… controller with a DPSU delivers a net current of 25 mA. This covers the
power consumption of 5 devices without a bus power supply (5 mA each required).
8 devices with a DPSU on one line deliver 200 mA. This covers the power con-
sumption for 40 devices or 38 devices plus OCI700 plus OZW771.
Even with devices having a low current requirement (< 3 mA), the number of
devices in a line must not exceed 64.
Refer to the data sheets for the power consumption of the new Synco devices.
2.2.2 Power consumption of the bus devices
To optimize the connectable devices set to "Decentral bus power supply = Off" and
the devices without a bus power supply, it is necessary to calculate the power con-
sumption from the KNX bus.
Power consumption values for Synco devices with "Bus power supply = Off":
•RMU7x0, RMU7x0B universal controllers 5 mA
•RMH760, RMH760B heating controllers 5 mA
•RMK770 boiler sequence controller 5 mA
•RMB795 central control unit 5 mA
•RMS705 switching & monitoring device 5 mA
•OZW775 central communication unit 5 mA
•QAX910 central apartment unit 5 mA
Power consumption values for Synco devices without a bus power supply:
•QAW740 room unit 7.5 mA
•RXB/RXL room controllers 5 mA
•RMZ792 bus operator unit 45 mA if directly connected to bus
(e.g. via bus socket)
without external power supply
•RMZ792 bus operator unit 5 mA if directly connected to bus
with external AC 24 V supply
•OZW771.xx central communication units 5 mA
Power consumption values for service interface, coupler and IP router:
•OCI700 service interface 5 mA
•Area/line coupler N140/13 6 mA Primary line (main line)
8 mA Secondary line (sub-line)
•IP router N146 10 mA From bus 1)
1) The Siemens IP router N146 consumes 10 mA from the KNX bus despite the
additional external auxiliary voltageAC/DC 24 V. Power consumption with
auxiliary voltage: 25 mAat DC 24 V, max. 800 mW.
Rule of thumb
Optimization
Notes