Industrial Ethernet Basics October 2006

1
Industrial Ethernet Basics October 2006
2
Ethernet TCP/IP and ISO/OSI model
Formatting Presenting
Routing Addressing
66.249.66.138
Transmission Signaling
3
Transmission and Signaling Basics

• Basic network arbitration is controlled by
  standard chips
• Collision detection
• Backoff mechanism
• Re-transmits
• Note this cannot be changed in software
• Some Industrial Ethernets use special chips to
  alter this basic characteristic

4
Transmission Signaling Cable Types

• Twisted Pair Category
• Shielded and Unshielded variants
• 4 and 8 conductor common
• Also capable of transmitting power
• Fiber Optic Category
• Multi-mode
• Single-Mode
• Glass and Poly hybrid media

100? UTP (Unshielded Twisted Pair )
100? STP (shielded Twisted Pair )
62.5/125? optical fiber
NOTE Twisted pair has a recommended segment
limitation of 100 meters, Fiber is 2 Km
5
Transmission Signaling Cable Types

• Coax cable
• Only used in old installations
• ControlNet hybrid systems

Coax cable

• Key Choice Factors
• Bandwidth
• Distance
• Noise Immunity
• Cost

6
Physical Layer - Cable Types

• Twisted Pair Category
• Cat3 Transmission up to 16 MHz for use in
  10BaseT systems
• Cat5 Transmission up to 100 MHz for use in
  10BaseT and 100BaseTX systems
• Cat5e Enhanced, up to 360 MHz to better support
  100BaseTX systems

7
Physical Layer - Cable Types

• Twisted Pair Category
• Cat6 Specified now in some new commercial and
  industrial installs, up to 400 MHz and common
  speeds of 1000 Mbps
• Twisted pair has a recommended segment limit of
  100 meters

8
Physical Layer - Cable Types

• Stranded vs Solid Wire
• Both UTP and STP come in stranded and solid wire
  varieties
• Stranded is most common and flexible for bending
  around corners
• Solid wire cable has less attenuation and can
  span longer distances, but is less flexible than
  stranded wire and cannot be repeatedly bent

9
Physical Layer - Wiring

• RJ-45
• EIA/TIA 568B specifies an 8 pin connection
• 2 pairs for data, 2 for voice
• 10BaseT systems use only the 2 data pairs
• Straight-through or crossover
• To connect devices together without going through
  a switch or router

• Conductors 1 2 are a twisted pair
• Conductors 3 6 are a twisted pair

10
Physical Layer - Wiring

• M12 (D-coded connector)
• Wiring is different
• Typically 4 and sometimes 8-conductor versions
• Straight-through or crossover

11
Fiber Media Basics

• Selection of a cable depends on functions such as
• Core material
• Singlemode or multimode
• Step or graded index
• Wave length of the transmitter

12
Multimode Fiber

• A multimode fiber has a dimension that affords
  space for several modes in a core
• There are two multimode cable categories
• Step index modes degrade or attenuate unevenly,
  resulting in lower bandwidth and distance
• Graded index refractive index reduces gradually
  from the cores centre towards the
  cladding--overall effect keeps the pulse together

The most common dimension of multimode cable is a
62.5 µm core and 125 µm outer cladding (the
cable is then designated 62.5/125).
13
Singlemode Fiber

• A singlemode fiber has such a fine core that it
  only supports one mode
• The transmitted light pulse is not distorted when
  traveling through the cable
• Long distance lack of attenuation gives superior
  performance
• High cost glass only, thin core is expensive to
  buy and install

The most common singlemode cable dimension is 9
µm core and 125 µm cladding (9/125)
14
Standard Fiber Connectors

• Common Fiber Connectors for Industrial
  Applications

15
Ethernet TCP/IP and ISO/OSI model
Formatting Presenting
Routing Addressing
66.249.66.138
Transmission Signaling
16
Ethernet Packet Basics

• Minimum of 26 overhead bytes (30 if using VLAN)
  are required in a packet
• Data can consume an additional 46 1500 bytes

IANA (Internet Assigned Numbers Authority) has
reserved the following three address blocks for
IP addresses in private networks 10.0.0.0 -
10.255.255.255 172.16.0.0 - 172.31.255.255 192.168
.0.0 - 192.168.255.255
17
Routing Addressing Topology

• Bus

• Ring

• Point to Point

• Mesh

• Star

With Ethernet, each Station has a unique MAC ID
preset at the factory and an abstracted IP
address that can be altered on the device
18
Routing Addressing Transmit modes

• Common Transmit modes

Combinations of Topology and Broadcast Modes can
cause severe network bandwidth reduction and
communications failure
19
Routing Addressing Enabling Equipment

• Hub connects together two or more computers to
  form one Ethernet segment
• Broadcasts packets out to all devices
• Low intelligence and cheap
• Also known as a repeater, concentrator, bridge

20
Routing Addressing Enabling Equipment

• Switch capable of inspecting packets,
  determining the source and destination and
  greatly reducing traffic
• Transmits packets only to intended devices
• Prevents collisions from occurring
• Can be used to diagnose network performance

21
Ethernet Switch Basics

• Unmanaged Requires no intervention from the
  user or software configuration
• also called Store and Forward or auto
  learning
• low intelligence and cheap
• Segments the network and prevents collisions
• Managed Can be setup by the user for
  intelligent inspection of packets and diagnostics
  of through traffic
• Can use rules to change packet pathways
• Abstracts addresses, creates redundancy, filters
  traffic
• Can be used to diagnose network

22
Key Managed Switch Functions

• Simple Network Management Protocol (SNMP) a set
  of protocols for managing network performance,
  finding and solving network problems, and
  planning for network growth
• Internet Group Management Protocol (IGMP)
  configures broadcast message behavior
• Quality of Service (QoS) Allows prioritization
  of packets to occur to improve performance for
  key channels

23
Key Managed Switch Functions

• Virtual LAN (VLAN) a network of computers that
  behave as if they are connected to the same wire
  even though they may actually be physically
  located on different segments of a LAN
• Spanning Tree Protocol (STP) algorithm to
  prevent wiring topology mistakes or create
  redundancy in a network

24
Open Ethernet Redundancy IEEE 802.1

• Rapid Spanning Tree Networks
• Single Ring Ring Coupling

Recovery time typically less than 50 ms per hop
(link between 2 switch)
25
Routing Signaling Routers

• Router joins multiple wired or wireless
  networks together
• Uses "routing table," to filter traffic, either
  incoming or outgoing, based on the IP addresses
  of senders and receivers
• Layer 3 Switch prioritize data on the MAC-level
  (layer 2) as above, or together with an IP
  header level i.e. as a router
• Each packet is given priority based on the
  content of the field, Type of Service (ToS)

26
Gateways, Firewalls, Bridges and Repeaters

• Repeater Forwards traffic between segments,
  often amplifying the signal in the process
• Bridge A bridge functions at the MAC layer,
  routing traffic only based on its physical address

27
Gateways, Firewalls, Bridges and Repeaters

• Firewall Used in security implementations,
  allowing intelligent routing of traffic across
  the bridge as programmed by authorized persons
• Gateway allows for the translation and
  management of communication between networks that
  use different protocols or designs

28
Formatting Presenting Industrial Protocols
Formatting Presenting
Industrial Ethernet
SRTP
PCCC
Melsec A Melsec Q
Routing Addressing
FINS
Modbus Uni-TE
Transmission Signaling
Modbus TCP
29
Most Popular Industrial Ethernets(IEC/ PAS 62xxx)

• EtherNet/IP PAS 62413, promoted by ODVA /
  Rockwell
• Network Type Common CIP Object model transferred
  by standard UDP/IP
• Topology All topologies are supported
• Media Connectors RJ45/M12 Cable
  Fiber/Standard Ethernet cable
• Specialties Common application layer with
  DeviceNet / ControlNet
• Clock synchronization (IEC1588) for real-time
  application
• Functional Safety specified with CIP safety
• PROFINET PAS 62411, promoted by PNO / Siemens
• Network Type Scalable TCP/UDP/IP based network
  for CBA and IO RT/IRT
• Topolog All topologies are supported, 100 Mbit/s
• Media Connectors RJ45/M12 Cable Fiber/
  Standard Ethernet cable
• Specialties Hard Real time for IO with special
  time based communication (IRT) Redundancy based
  on Hyperring (Hirschmann/Siemens) Functional
  Safety with PROFISAFE

30
Most Popular Industrial Ethernets(IEC/ PAS 62xxx)

• MODBUS TCP
• PAS 62030, promoted by MODBUS-IDA / Schneider
• Network Type Standard TCP/UDP/IP based
  Client/server protocol
• Topology All topologies are supported Transfer
  speed up to 1 Gbit/s
• Media Connectors RJ45/M12 Cable
  Fiber/Standard Ethernet cable
• Specialties RTPS for real-time over UDP/IP
• Determinism depends on network load and
  topology

31
Most Popular Industrial Ethernets (IEC/ PAS 62xxx)

• EtherCAT PAS 62407, , promoted by Beckhoff
• Network Type Token passing master/slave
• Topology Trunk and Drop
• Media Connectors RJ45/M12 Cable
  Fiber/Standard Ethernet
• Specialties Standard master/scanner interface but
  custom slave/adapter
• Clock synchronization for real time
  application
• Powerlink PAS 62408, promoted by Bernecker
  Rainer
• Network Type Scalable TCP/UDP/IP based network
  with parallel stack
• Topology All topologies are supported 100
  Mbit/s
• Media Connectors RJ45/M12 CableFiber/
  Standard Ethernet cable
• Specialties Software upgrade to existing hardware
  enables real time performance with special
  time domain multiplexing

32
Most Popular Industrial Ethernets (IEC/ PAS 62xxx)

• Foundation Fieldbus
• PAS 62453-5, promoted by Fieldbus Foundation /
  Process
• Network Type Standard TCP/UDP/IP based
  Client/server protocol
• Topology All topologies are supported transfer
  speed up to 1 Gbit/s
• Media Connectors RJ45/M12 Cable
  Fiber/Standard Ethernet cable
• Specialties Can run over any media
• Support for profiles, containers and remote
  initialization

33
Ethernet Real time Architectures
34
(No Transcript)