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Building Technologies Basic documentation: Communication via the KNX bus CE1P3127en
HVAC Products Engineering notes 30.08.2007
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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