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Siemens
KNX bus communications
CE1P3127en
Building Technologies
Large plants
2013-04-08
8
Large
plants
8.1
Engineering and commissioning
In large projects, observe the following points during the engineering and
commissioning.
For all lines, observe the distances and line lengths (see Section 2.3.1). If the
topology exceeds the prescribed limits, use area/line couplers.
Max. 64 bus devices may be installed on one line. In plants with more than 64 bus
devices, the bus devices must be distributed to different lines and/or areas (see
Section 2.1.2).
When structuring large plants, LTE-compatible area/line couplers are required (see
Section 1.4).
For the "KNX to IP network" connection, LTE-compatible IP routers are required
(see Section 1.4).
The area/line couplers and IP routers must contain the predefined LTE filter table
(see Section 8.2).
Alarm sinks should be on the same line or the next higher line in the hierarchy (see
Section 8.1.1, example 2). Alarm sinks:
OZW771 central communication unit
OZW775 central communication unit
OZW772 web server
RM… controllers with enabled fault relay.
Devices with room functions should be located on the same line as the devices
with which they exchange data via KNX in LTE-Mode, i.e.:
Synco QAW740 room unit
Synco RM… controllers
RXB/RXL room controllers
Synco RMB795B central control unit
Room thermostats RDG/RDF/RDU
Synco central control unit RMB795B
Synco RM… controllers for room control combinations (see Section 9.3)
Only one bus device in the network may be configured as the time master (see
"Time synchronization" in Section 6.1.2).
A search via ACS for devices in all areas and lines only works with correctly
addressed area/line couplers.
Observe the following rules when addressing zones:
The zone addresses, which can be filtered, are permanently predefined in the
LTE filter table (see Section 8.2). For this reason, both the assignment of
devices to areas and lines, and the addressing of the zones must be planned
with extreme care.
Keep data traffic to the minimum by creating "communication islands" (see
Section 1.4).
There is a limit to the number of LTE telegrams that can be transmitted via
area/line coupler and IP router (see Section 8.2.4).
Large plants
Distances and line
lengths
Number of bus devices
Area/line couplers
IP routers
Predefined filter table
Alarm sinks
Devices with
room functions
Clock time master
ACS790 software
Design rules for zone
addressing
