Two of the most popular factory automation (FA) technologies in North America are Ethernet / IP and EtherCAT. Ethernet is Local Area Network (LAN). Standardized Ethernet technology is noted as IEEE802. Each system is a very different protocol to the other. An important point here to make is that industrial Ethernet is more complex than the usual form of Ethernet that serves many data services in IT.
EtherCAT uses an advantage called “processing-on-the-fly”. The acronym CAT refers to Control Automation Technology. The EtherCAT master is where the telegram begins. Applications are real-time. Basically, the master operates on the single message in – single message out. Data sent is stored until it can be processed which happens at the node level resulting in high speed and efficient operations. All nodes ‘see’ all data as it passes through. A message from the node is added after a string of data is read. All nodes will see the other nodes message sent, so topology is flexible.
The protocol is also flexible with good safety features resulting in this technology being a very popular choice. CAT uses separate lines for sending and receiving data. CAT works well with many industrial automation products allowing it to support a high number of secondary nodes within the network thereby eliminating a bus system to manage nodes and connections.
The secondary devices embed special ASIC (Application-Specific Integrated Circuit) hardware to ensure fast processing. Each drive on the network is assigned a unique address through the hardware.
One predecessor to EtherCAT is Ethernet /IP. The development of this product began nearly 20 years ago by Allen Bradley. This quickly became well established in the North American market. It uses industrial Ethernet and standard Ethernet hardware including both TCP/FP and UDP/IP for data transfer; Ethernet / IP uses TCP-IP and establishes real-time data messaging.
Presently, two types of products exist for data transfer between the components – twisted-pair and fiber optic cables. Twisted-pair cables transfer signal over copper wire and use shielding to block industrial noise. Fiber optics transmit light pulses, which are also immune to noise. Noise is the enemy of data communications as it can block signals or introduce unintended ones. Regardless of the type of cable used, it is necessary to ensure the jacketing can also withstand the physical environment it is placed into.
There is a lot to choose from when determining how to set up an industrial network. Many brands of equipment exist and more will come. It is important to have a reliable supplier of not just the larger systems but also the components needed to set up a network. MISUMI offers an extensive catalog of industrial Ethernet products and cables. Click here to view the products now.