Welcome back to the second part of "How to Choose the Right Industrial Ethernet Standard," which is aimed at engineers who have decided to take advantage of Industrial Ethernet in their systems. This series will cover several common Industrial Ethernet communication protocols to help you choose the best standard for your application. You can also read the previous blog post about Sercos III. In this section, I will detail EtherCAT, its end applications, and how it works. Beckoff AutomaTIon invented EtherCAT. It has been under the EtherCAT Technology Group (ETG) framework since 2003, and the EtherCAT Technology Group is an industrial fieldbus organization of approximately 2,600 member companies. EtherCAT is commonly found in factory automation, semiconductor tools, packaging robotics, and other applications. One of my favorite examples of non-industrial applications is the water dance show in Disney, where EtherCAT controls the light display. At the technical level, EtherCAT is the master-slave network architecture shown in Figure 1. The EtherCAT slave has 2 Ethernet connectors to support a simple line topology. For redundancy purposes, a ring topology can also be supported, in which case the EtherCAT master must have 2 Ethernet ports. An EtherCAT network can support up to 65,535 slaves. Figure 1: EtherCAT master-slave example network with EtherCAT data frame flow Only the EtherCAT master generates an EtherCAT data frame; all slaves receive and process this data frame. The last slave returns this EtherCAT data frame, which is returned to the master after undergoing all slaves (no further processing required). This EtherCAT data frame has reserved space for data processing for each slave, and all slaves do not change the length of the data frame itself. This is a bit like a train that has multiple compartments and seats for passengers, each with a designated compartment or designated seat. EtherCAT allows addressing to the "seat" layer - while data processing is done on the data bits. An EtherCAT master requires only one standard Ethernet MAC peripheral because the master has no specific need to process EtherCAT data frames in real time. The master only needs to trigger the EtherCAT data frame with an accurate time base. An EtherCAT slave requires specific Ethernet hardware (EtherCAT MAC) support—usually an application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA) as shown in Figure 2 – because it needs to be processed EtherCAT data frames entered during the run. This means that the EtherCAT MAC processes EtherCAT data frames while receiving data frames. A typical EtherCAT device has a port-to-port delay of 1 μs between received and transmitted data frames. Figure 2: EtherCAT Slave with an ASIC/FPGA and External Processor The EtherCAT standard does not support other types of Ethernet data frames in an EtherCAT network. This is mainly to keep the real-time Ethernet channel unblocked for EtherCAT data frame processing. In the case of non-EtherCAT data frames (Ethernet types that do not match EtherCAT) in the EtherCAT network, the EtherCAT slave will destroy the data frame by invalidating the Data Frame Checksum (CRC). This makes non-EtherCAT data frames unusable in standard Ethernet devices, and they will eventually stop "polluting" the EtherCAT network. By encapsulating Ethernet data frames in an EtherCAT data frame, standard Ethernet data frames (Transmission Control Protocol/Internet Protocol (TCP/IP), User Datagram Protocol (UDP)) can be transmitted over the EtherCAT network. This is done through different EtherCAT system configurations located on top of the EtherCAT host processor protocol stack. One example of a system configuration is to implement Ethernet with EtherCAT. Other features and functions of the EtherCAT device include: Distributed Clock—High-precision time synchronization method on the slave and master. Fast Link Disconnect Detection with Loopback Support (requires Ethernet Physical Layer (PHY) Transceiver Support) - When the Ethernet PHY detects a link down, it notifies the EtherCAT hardware. Within 10 μs, the EtherCAT hardware will loop back to the EtherCAT data frame. Check out TI's TLK1xx Ethernet PHY transceiver family, which supports fast link disconnect features. Using an ASIC or FPGA in EtherCAT increases cost and board area. An alternative solution is to use the PRU-ICSS peripherals in many TI Sitara processors. For example, TI offers PRU-ICSS firmware for AM335x processors, eliminating the need for an external FPGA for EtherCAT slaves (Figure 3). You can use the TMDSICE3359 evaluation board to evaluate TI's EtherCAT slave solutions. Figure 3: EtherCAT slave with integrated TI Sitara processor I hope this blog post will give you an idea of ​​the functionality of EtherCAT. To learn more about the Industrial Ethernet standard, don't forget to read the other blog posts in this series. Other resources View the TI Design reference design for the EtherCAT communication development platform. Read the previous blog post in this series, "How to choose the right Ethernet standard: Sercos III." Read the blog post about "How to Make Industrial Ethernet as Simple as Standard Ethernet." Download the "Industrial Communications Solutions Guide." Read the white paper, "EtherCAT on Sitara Processors," which includes an introduction to EtherCAT. Learn more about Industrial Ethernet communication protocols in this white paper. Learn more about the EtherCAT standard on the ETG website. Original link: The JUMP WELL brand embedded scan code module is small, light and easy to install. The scanning window is very large. 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