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Industrial Ethernet Communication Protocols
second (Gbps) range going forward. The most prominent real-time
Ethernet protocols today include EtherCAT, EtherNet/IP, PROFINET,
POWERLINK, Sercos III, Modbus TCP, and CC-Link IE. Ethernet also
enables exible network topologies that scale with the number of
network nodes.
Ethernet communications using standard TCP/UDP/IP are
nondeterministic, with typical cycle times greater than 1000
ms, and packets subject to collision on the wire. Some Industrial
Ethernet protocols use a modied Media Access Control (MAC) layer
to achieve low latency and deterministic responses.
Table 1 illustrates the umbrella organizations responsible for each
Industrial Ethernet type discussed here.
Figure 5 on the following page illustrates how the Industrial
Ethernet protocols relate to standard TCP/UDP/IP based Ethernet,
together with their MAC layer modications. Ethernet/IP, Modbus,
and standard PROFINET protocols are completely TCP/UDP/IP
based. Standard Ethernet switches and controllers can be used in
the network (Figure 5a). For PROFINET RT and POWERLINK, process
data is carried over TCP/UDP/IP with timing controlled by a process
data driver. Standard Ethernet switches, hubs, and controllers can
be used in the network (Figure 5b). For PROFINET IRT, CC-Link IE,
SERCOS, and EtherCAT, process data is carried over TCP/UDP/IP with
timing controlled by a process data driver. Special Ethernet link
layer/MAC hardware is required for protocol slave devices to realize
determinism (Figure 5c).
Nearly all Industrial Ethernet protocols, if not entirely TCP/UDP/IP
based, provide some mechanism to encapsulate and carry standard
Ethernet frames, (for example Ethernet-Over EtherCAT - EOE).
When using an Ethernet packet snier such as Wireshark,
most Industrial Ethernet frames are identied by checking the
ETHERTYPE ID eld. Table 2 illustrates how each of the dierent
Industrial Ethernet types are detected using the Ethernet frame
ETHERTYPE ID.
Table 1: Industrial Ethernet organizations
Other Fieldbus
10%
EtherNet/IP
15%
PROFINET
12%
EtherCAT
7%
Modbus-TCP
4%
POWERLINK
4%
Other Ethernet
10%
DeviceNet
4%
CANopen
4%
CC-Link
6%
Modbus-RTU
6%
PROFIBUS DP
12%
WLAN
4%
Other Wireless
1%
Bluetooth
1%
Industrial Ethernet: 53% (46)
Annual growth: 22% (22)
Fieldbus: 42% (48)
Annual growth: 6% (4)
Wireless: 6% (6)
Annual growth: 32% (32)
Figure 3: Industrial Ethernet Market Share 2017: Source: HMS
Industrial Ethernet
Protocol
Organization Contact
PROFINET PNO www.pro bus.com
POWERLINK ESPG www.ethernet-
powerlink.org
Ethernet/IP ODVA www.odva.org
EtherCAT ETG www.ethercat.org
SERCOS III SERCOS
International
www.sercos.org
MODBUS TCP Modbus
Organization
www.modbus.org
CC-Link IE CLPA www.cc-link.org