ANSI/CEA709 (EN14908) Standards August 2006 - PowerPoint PPT Presentation

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ANSI/CEA709 (EN14908) Standards August 2006

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  1. ANSI/CEA709 (EN14908) Standards August 2006 Vijay Dhingra 04H1122

  2. Background • Data networks interconnect computers, servers, and printers • Control networks connect sensors, actuators, displays, and other machines to each other, to remote monitoring sites, and to the Internet • All control networks perform a common set of functions: they sense, process, actuate, and communicate Internet

  3. Control Network Technology Requirements • Robust, reliable communications • Peer-to-peer protocol supports multiple media, efficient addressing and authentication • No single point of failure in the control system • Predictable, autonomous applications regardless of network traffic • Open standards based and Interoperable products • Large Ecosystem of cost effective solution • Best of breed products in commercial and home market • Confidence and leverage in a future proof environment

  4. Multiple Media Support • Control applications require flexibility in selecting communication medium • Protocol and routing technology that allows multiple media (Mixed as needed within system): • Power line • Twisted pair • Fiber optic • RF • Coaxial cable • Infrared • IP • Interface with other home networking standards/protocols • With simple application layer bridging

  5. LONWORKSControl Networks • Flat Peer-Peer Network Architecture • Eliminate complex cabling • Lower installation and maintenance costs • Eliminate proprietary & closed gateways, and central controllers • Simplify HMI development • Open • Choose interoperable components from multiple vendors

  6. ANSI/CEA-709.1-BControl Networking Protocol

  7. ANSI/CEA-709.1-B Protocol • An open standard protocol for control applications • Control applications have different requirements than data applications • TCP/IP is an example of a data networking protocol • Reference document available from Global Engineering • Protocol implementations are available from multiple vendors • Protocol can be ported to any processor • Echelon’s implementation is called the LonTalk® protocol • Echelon’s Neuron® firmware includes the LonTalk protocol • Echelon development systems include a royalty-free unlimited license to use the Neuron firmware implementation

  8. ANSI/CEA-709.1 Protocol Layers Application Presentation Session Transport Network Data Link Physical • ANSI/CEA-709.1 is layered • As recommended by the International Standards Organization Open Systems Interconnect (ISO OSI) reference model • OSI layers ensure that the required services are provided without unexpected interactions between the services • Device manufacturers only need to change the application Physical Media

  9. ANSI/CEA-709.1 Protocol Layers

  10. A Typical ANSI/CEA-709.1 Packet Layer 2 Header Layer 3 Address Information Layer 4 Service Type Layer 5/ 6 Header DATA Layer 2 CRC 2 Bytes Unsigned Long 2 Bytes Network Variable Selector 2 Bytes Service Type ID Transaction Num 1 Byte Addr Format, Domain Length Source Addr (Subnet/Node) Dest Addr (Group) Domain ID (Zero Len Domain) 1 Byte 2 Bytes 1 Byte 0 Bytes Backlog Priority Alt Path 1 Byte 12 Bytes

  11. Layer 1—Physical Layer • Electrical interconnect • Transmission of raw bits over a communication channel

  12. Physical Layer—Common Channel Types • Optimize cost and performance for a broad range of control applications

  13. PL-20x TP/FT-10 TP/XF-1250 IP-852 Typical Channel Capacities • PL-20x Channels • PL-20N ~20 packets/sec • PL-20C ~18 packets/sec • PL-20A ~11packets/sec • TP/FT-10 Channel • Peak: ~225 packets/sec • Sustained: ~180 packets/sec • TP/XF-1250 Channel • Peak: ~720 packets/sec • Sustained: ~576 packets/sec • IP-852 Channels • ~10,000 packets/sec • Supports aggregation

  14. Physical Layer—TP/FT-10 Channel • Defined by ANSI/CEA-709.3-A Free-Topology Twisted Pair Channel Specification • Media is free topology twisted pair with optional link power • Supports commonly available unshielded and shielded 0.50mm (24AWG) to 1.3mm (16AWG) twisted pair wires • Polarity insensitive wiring • Reduces installation and maintenance costs • Up to 64 devices on a single network segment • Or 128 devices along with a link power source • Available in cost-effective device-on-a-chip • With all-in-one transceiver, application processor, and memory

  15. A-Band 86kHz 75kHz Physical Layer—PL-20 Channel • Advanced technology for reliable communication • Dual carrier frequency operation • Digital signal processing • Worldwide operation • Meets FCC, Industry Canada, Japan MPT, and European CENELEC EN50065-1 regulations regulations • ANSI/CEA-709.2 compliant • European utility support • Dual frequency DSP performance in the A-Band for AMR/DSM applications • Available in cost-effective device-on-a-chip • Transceiver, application processor, memory • Proven technology • Millions of devices installed worldwide C-Band 132kHz 115kHz

  16. Layer 2—Link Layer • Media access and framing • Ensures efficient use of a single communications channel • Raw bits of the physical layer are broken up into data frames • Link layer defines when a device can transmit a data frame • Also defines how destination devices receive the data frames and detect transmission errors • Features • CRC error checking • Media access—predictive p-persistent CSMA • Priority • Collision avoidance

  17. Busy Channel Packet Cycle Packet Packet Non-priority Slots Link Layer—Media Access • Predictive p-persistent CSMA • Channel access is always randomized over time slots • Number of time slots are varied based on collision avoidance algorithm • 16 to 1008 slots

  18. Busy Channel Packet Cycle 1 2 3 ... n Packet Packet Priority Slots Non-priority Slots Link Layer—Media Access Priority • Configurable priority messages • Reserved time slot • Reduces overall channel bandwidth • Priority slot number is assigned at installation time • No collisions possible during priority portion of packet cycle following preceding packet • Highest priority message has predictable response time

  19. Link Layer—Media Access Benefits • Linear response time over 99% of channel bandwidth • Critical for open media such as power line • Remove and attach devices without halting communications • Predictable performance for high-priority messages

  20. Link Layer—709.1 MAC vs. Ethernet from: Computer Networks, Andrew S. Tanenbaum, Fourth Edition, 2003.

  21. Layer 3—Network Layer • Message delivery • How data frames are routed from a source device to one or more destination devices • Physical address • 48-bit Neuron ID—used for initial configuration • Logical addresses • Domain Identifies subsystem on open media or large system • Subnet Subset of a domain typically associated with a channel • Node Identifies device within subnet • Group Additional device identifiers independent of subnet 1 SUBNET 1 127 1 SUBNET 2 127 127 1 SUBNET 3 GROUP 1 1 SUBNET 4 127 1 127 SUBNET 255 DOMAIN (32,385 Devices)

  22. Network Layer—Addressing Modes • Optimize bandwidth with multiple addressing modes • Application communications only requires 3- or 4-byte network addresses • Send messages to many devices using only a single 3-byte network address

  23. Network Layer—Capacity Room to grow from a few devices to millions • 18,446,744,073,726,329,086 domains • 255 subnets per domain • 127 devices per subnet • 32,385 devices per domain • 256 groups per domain • 64 devices per acknowledged group • 32,385 devices per unacknowledged group

  24. Network Layer—Routers Domain Subnet 1 Subnet 1 Subnet 2 ... • Extend channel segments • Improve reliability • Increase overall bandwidth • Simplify network configuration • Routers are transparent to devices and applications Channel Router Router Repeater Group 1 Subnet 5 Subnet 3 Router Group 1 Repeater Group 2 Subnet 4

  25. R R R Layer 4—Transport Layer • End-to-end reliability—allows reliable delivery of message packets • Three message delivery services • Acknowledged • Sending device requires acknowledgment from all receiving devices • All acknowledgments are end-to-end • Automatic retries if acknowledgement not received • Repeated • Configurable number of messages per transaction • Conserves bandwidth with large groups • Better response time • Three repeats provides > 99.999% probability of delivery • Unacknowledged • One message per transaction • Conserves network bandwidth and provides highest performance • Duplicate detection prevents repeated messages to the application R S Acknowledged - Unicast S R Acknowledged - Multicast R S Repeated- Unicast or Multicast R S Unacknowledged - Unicast or Multicast

  26. R R R Layer 5—Session Layer • Adds control to the data exchanged by the lower layers • Request/response service • Used for device management, fetching values, and requesting other remote actions • Authentication • Verifies identity of message sender… R S S R

  27. Session Layer—Authentication Sender Authenticated Message Receiver • Verifies identity of message sender • Uses a 48-bit secret key known by each device • Sender must provide correct reply to 64-bit random challenge from the receiver 64 bit Random Challenge Key used to transform challenge Key used to compare response to value transformed locally. Challenge Response Acknowledgment

  28. Room Temp Temp Set Point Temp Sensor (Made in USA) Boiler System (Made in Europe) 23 Set Point Setpoint Display (Made in Korea) Layer 6—Presentation Layer • Data exchanged using network variables • Propagation automatically handled by Neuron firmware • Provides fastest and most compact code • Devices from different manufacturers can exchange data with a common interpretation

  29. Alarm Presentation Layer—Connections • Sensors “publish” information, and actuators “subscribe” to information • Devices are logically connected • Connections do not affect device applications Feedback Room Occupied Motion Brightness Motion Detector Lamp 0% - 100% Key Code Control Knob Intruder Arm / Disarm Key Pad Alarm Bell

  30. Presentation Layer—Standard Types • Standard network variable types • Over 170 standard types defined at types.LONMARK.org • XML definitions available for easy input/translation/interpretation by other systems

  31. Presentation Layer—Standard Formatting • Ensures consistent data presentation in tools and HMIs • Example • A SNVT_temp_p value of 2940 is displayed as follows: 29.4 degrees C 84.9 degrees F 52.9 degrees F

  32. Layer 7—Application Layer • Defines standard network services that use data exchanged by the lower layers • Network configuration and diagnostics • File transfer • Application configuration, diagnostics, management, and specification • Standard profiles • Alarming • Data logging • Scheduling • More than 60 others

  33. Application Layer—Application Configuration • Configuration properties characterize the behavior of a device in the system • Types define data encoding, scaling, units, default value, range, and behavior • Standard configuration property types defined at types.LONMARK.org • XML definitions available for easy input/translation/interpretation by other systems

  34. Node Object Mandatory Network Variables nviRequest nvoStatus nv1 nv2 SNVT_obj_request SNVT_obj_status Optional Network Variables nvoAlarm2 nviTimeSet nv10 nv3 SNVT_alarm_2 SNVT_time_stamp nvoAlarm nv4 SNVT_alarm nviDateEvent nvoDateResync nv9 nv11 SNVT_date_event SNVT_switch nviFileReq nvoFileStat nv5 nv6 SNVT_file_req SNVT_file_status nvoFileDirectory nviFilePos nv8 nv7 SNVT_address SNVT_file_pos nvoLogStat nviLogReq nv13 nv12 SNVT_log_status SNVT_log_req Configuration Properties Mandatory Optional Device Major Version Device Minor Version Functional Block Major Version Functional Block Minor Version Location Maximum Status Send Time Minimum Send Time (Send Throttle) Network Configuration Source Application Layer—Application Specification • Functional block • Portion of a device’s application that performs a task • Receives configuration and operational data inputs • Processes the data • Sends operational data outputs

  35. Application Layer—Standard Profiles