Introduction to Building Communication Protocols and Integration to Siemens Desigo System Considerations

1. Introduction to Building
Communication Protocols and
Integration to Siemens Desigo
System Considerations
Mahmoud Sayed Ahmed
Senior BMS Commissioning Engineer
www.linkedin.com/in/mahmoud-s-ahmed

2. Rules for communicating
• For example, an Englishman and German are talking about animals on
the telephone.
• Even if they can hear each other clearly, they may not understand
each other.

3. Communication Protocol
• A protocol is a set of rules that governs how two devices communicate
with each other.
• A protocol must define, for example:
• Who is allowed to access the transmission medium and when
• How to detect data transmission errors and what happens when an error is
discovered
• What happens when a receiver receives more data than it can process at a time
• How to ensure that data frames are sent to the right destination

4. Communication Protocol
I like
rabbits
Ik hou van
konijnen
Ik hou van
konijnen
J’aime les
lapins
Ik hou van
konijnen
Ik hou van
konijnen
By Fax

5. OSI model
• OSI “Open Systems Interconnection” Reference Model was
developed by the “International Organization for Standardization” ISO
in 1979.
• The OSI model is a layered model that describes how information
moves from an application program running on one networked
computer to an application program running on another networked
computer.

6. OSI Model
Provides communication services and interfaces to applications (EX: File transfer,
Electronic mail, WWW)
Data formatting, translation, encryption, and compression (EX: ASCII, JPEG)
Manages the dialog, synchronizes the data transmission this layer establishes,
maintains, and terminates sessions between applications (EX: SMTP, SNMP, Telenet)
Point-to-point error checking and data segmentation (EX: TCP, UDP)
Represents logical routing between two computers (EX: IP)
Transfer data and detect errors on the physical layer (MAC/LLC, Token ring, PPP, X.25)
Sends and receives bits on the physical medium , Electrical and mechanical
specifications What signal state represents a binary 1 (EIA-232, EIA-485, 10BASE-T)
7 Application 7 Application
6 Presentation 6 Presentation
5 Session 5 Session
4 Transport 4 Transport
3 Network 3 Network
2 Data Link 2 Data Link
Computer 1 Computer 2
1 Physical1 Physical
Physical medium between two computers (EX: CAT5
or CAT6 cables)

7. OSI Model
• The unit in which a certain
layer handles data is called a
Protocol Data Unit (PDU).
• Some layers add layer-specific
information to the data.
• This information added by the
layers’ protocols can be in the
form of a header, a trailer, or
both.

8. OSI Model
• The unit in which a certain
layer handles data is called a
Protocol Data Unit (PDU).
• Some layers add layer-specific
information to the data.
• This information added by the
layers’ protocols can be in the
form of a header, a trailer, or
both.

9. OSI Model for Building Automation Protocols
• Any given protocols can be defined using some or all the OSI layers.
• The missing layers in the implementation could either indicate a lack
of implementation, or an open implementation.
Physical
Data link
Network
Transport
Session LonTalk Konnex
Presentation LonTalk Konnex
Application MODBUS M-Bus LonMark Konnex
MODBUS
EIA-232, EIA-485
M-Bus
M-Bus
LonTalk
LonTalk
LonTalk
LonTalk
BACnet Konnex
BACnet Konnex
Konnex
Ethernet,
LonTalk, EIA-232
Konnex
BACnet

10. Protocol Implementations Considerations
1. Do I need routers or gateways?
• Some protocols can be integrated directly to management level
(Desigo Insight or Desigo CC) and some protocols can be intrgrated
through gateways or routers (TXM1(2).Open, PXC001(E).D, PXG3.L or
PXG3.M.
 BACnet: Building Automation Control network,
Revision 1.13
 OPC Client: OLE for Process Control OPC DA 2.05,
3.0
 ONVIF: Standard for IP video camera systems by
Siveillance VMS
 Modbus TCP: Modbus IP communication protocol
 SNMP: SNMP Agents monitoring (V1 and V2)
 IEC 61850
Desigo CC V3

11. Protocol Implementations Considerations
1. Do I need routers or gateways?
a. BACnet/LON can be integrated via PXG3.L router and BACnet/MSTP can be
integrated via PXG3.L or PXG3.M routers.

12. Protocol Implementations Considerations
1. Do I need routers or gateways?
b. LonWorks can be integrated via PXX-L11 (60 Device) or PXX-L12 (120 Device)
used modular PXC controllers.

13. Protocol Implementations Considerations
1. Do I need routers or gateways?
c. Modbus can be integrated via PXC001.D or PXC001.E.D
PXC001(.E).D >>250 points
PXC001(.E).D +PXA40-RS1>>800 points
PXC001(.E).D +PXA40-RS2>>2000 points

14. Protocol Implementations Considerations
1. Do I need routers or gateways?
d. Modbus can be integrated via TX Open modile connected to PXC modular
Controller or PXC22.1.D/-E.D and PXC36.1.D/-E.D
TXI2.OPEN >>160 points
TXI2-S.OPEN>>40 points
TXI1.OPEN>>100 points

15. Protocol Implementations Considerations
1. Do I need routers or gateways?
e. KNX (TP) can be integrated via PXC001.D or PXC001.E.D. KNX/IP should be
connected through KNX/IP gateway.
PXC001.D/E.D >>2000 Points

16. Protocol Implementations Considerations
1. Do I need routers or gateways?
f. M-Bus can be integrated via PXC001.D or PXC001.E.D or TX Open module
and and M-Bus Signal Converter, With point limitations same as Modbus.
Signal Converters:
PW3 >> 3 Devices
PW20 >> 20 Devices
PW60 >> 60 Devices
WZC-P250 >> 250 Devices

17. Protocol Implementations Considerations
2. Network topologies
Bus topology Tree topology

18. Protocol Implementations Considerations
2. Network topologies
Star topology Ring topology

19. Protocol Implementations Considerations
3. Physical medium (Cables types and routing)
Shielding in cables protects the cable from external threats, such as
electrical interference (EMI). It also prevents cable signals from interfering
with surrounding cables and equipment.
Cat5 cableUnshielded Twisted Pair (UTP)
cable
Shielded Twisted
Pair (STP) cable
JY(ST)Y Cable

20. Protocol Implementations Considerations
4. Date transmission rate, Bits per Second (bps) or Megabits per
Second (Mbps)
5. Maximum allowed devices per network.
6. Maximum cable length between two node and maximum total
cable length.
7. Do I need repeater or bus power supplies?

21. References
Title Document ID# Publisher
BACnet Application Guide for Consulting Engineers 125-1984T Siemens Building Technologies USA
ANSI/ASHRAE Standard 135-2004 ISSN 1041-2336 ASHRAE
Desigo™
Ethernet, TCP/IP, MS/TP and BACnet
Technical principles
CM110666en_10 Siemens Building Technologies
Desigo™
Building automation system 6.1
Technical Principles
CM110664en_01 Siemens Building Technologies
Desigo™ Room automation
Engineering, mounting and installation
Manual
CM111043en_10 Siemens Building Technologies
DesigoCCV21_3rd party BACnet_EDE_Step-By-Step-
Guide
---------------------- Siemens Building Technologies
Building Automation
Communication Systems with EIB/KNX,
LON and BACnet
ISBN: 978-3-540-
88828-4
Springer
Communication in building automation ----------------------- Siemens Building Technologies