Ethernet vs. EtherCAT

Computer networks rely on Ethernet industrial protocol (Ethernet/IP) and Ethernet for control automation technology (EtherCAT) protocols to send data between machine endpoints. Both technologies use the physical layer and data link layer of the Ethernet infrastructure, enabling them to use the same CAT5 network cables. However, they diverge considerably in the application, with EtherCAT well-suited for time-critical motion control capabilities. 

Learn more about the differences between EtherCAT and Ethernet, including the benefits and disadvantages of these protocols.

The Main Difference Between Ethernet and EtherCAT

EtherCAT performs with faster communication speed, higher bandwidth and less jitter, making it the ideal technology for rapid, real-time processing of motion control applications. 

In contrast, Ethernet is more appropriate for less time-sensitive applications, such as monitoring, testing, and implementing new software. Ethernet performs with slower communication speed, lower bandwidth, and higher jitter than EtherCAT. 

While they are common communication network protocols, Ethernet and EtherCAT do not share compatibility with specific Ethernet layers, such as transmission control protocol (TCP) and user datagram protocol (UDP). Ethernet uses TCP and UPD to transmit data between computer equipment, while EtherCAT evades TCP and UPD for more rapid and precise data communication. 

EtherCAT can also support more nodes per network than Ethernet, which means EtherCAT can connect to many different computers, such as servo drives and analog or digital devices.

What Is Ethernet? 

Ethernet or Ethernet/IP is a widely used communication protocol that facilitates data exchange between devices with a network of physical cables. It defines data structure and messaging with common industrial protocol (CIP). Ethernet supports flexible network topologies, such as bus, mesh, ring, hybrid, and star configurations, allowing stable and efficient connection with multiple devices. 

Each device on the Ethernet requires a unique IP address that should be part of the same subnet to communicate effectively. Ethernet operates on top of a TCP stack and may be used for real-time communication, utilizing cables and switches that easily integrate with existing IT infrastructures. It's a popular protocol connecting offices, hospitals, school networks, businesses, and organizations. 

What Is EtherCAT?

EtherCAT is a high-performance protocol specifically designed to automate control systems. It follows a master-slave architecture and uses a logical ring topology, enabling efficient and deterministic transmission of data frames across the network. Besides ring topology, EtherCAT is used to support tree and star topologies and can connect with more devices than Ethernet on a single network. 

EtherCAT is primarily known for its fast and efficient data processing capabilities. Unlike other communication protocols, it transmits data to each device without storing or replicating it. 

As the master device sends data, each node extracts input data and adds output data for rapid and continuous communication. This single-pass approach enhances communication speed and ensures precise transmission across the network. As such, Ethernet is the most appropriate protocol for synchronized, time-sensitive motion control of computer systems.  

Advantages of EtherCAT

Rapid data transmission makes EtherCAT highly beneficial for many reasons. Below are its key advantages:

• Network efficiency: High-speed data transfer boosts network performance with smoother and more reliable on-time communication. It minimizes network delays and prioritizes data transmission. EtherCAT allows coordination between input and output data, positioning data, drive control and other devices, resulting in efficient coordination.
• Real-time control: EtherCAT processes data in real time, enabling timely and deterministic network communication between devices with minimal jitter. It facilitates seamless synchronization of motion control from the outset.
• Improved scalability and integration: EtherCAT supports various device types while eliminating the need for additional adapters and gateways. It does not require unique IP addresses and automatically assigns devices in the network, enabling easy connectivity.
• Increased data space: EtherCAT's master-slave architecture transmits data without requiring intermediate storage space. Unlike Ethernet, it can simultaneously process incoming and outgoing data from multiple computers in the network.

Disadvantages of EtherCAT

While EtherCAT has ultra-fast data processing, it may pose two main disadvantages:

• Setup challenges: Implementing EtherCAT typically requires application-specific integrated circuit (ASIC) hardware for its slave device. Its distinct data model can be challenging to grasp for those unfamiliar with its architecture. Understanding and fully maximizing the system may pose a learning curve.
• Compatibility issues: Its design may not always be readily compatible with legacy systems that rely on the traditional Ethernet protocol stack, such as Modbus TCP or Open Platform Communications Unified Architecture (OPC UA). It may still require additional software support, which can add costs. Certain manufacturers may require proprietary implementation, making the setup more complex.

Advantages of Ethernet

Both Ethernet and EtherCAT provide stable communication protocols for computer networks and automation systems. However, Ethernet offers these specific advantages:

• Familiarity with integration: The use of standard Ethernet and hardware makes it highly accessible for most IT teams. While it may need additional hardware support for real-time data transmission, it uses common Ethernet cables and switches. Straightforward integration with existing infrastructure minimizes setup delays.
• Traditional network compatibility: Ethernet is already compatible with elevated layers of the Ethernet protocol stack, including Modbus TCP, UDP and OPC UA. It supports simplified communication throughout the network, which helps streamline data and communication management. 
• Cost-effective setup: Since Ethernet uses off-the-shelf Ethernet hardware, such as inexpensive CAT5 cables and standard switches, it offers a low-cost solution for industrial networks. This helps reduce setup and maintenance expenses.

Disadvantages of Ethernet

Many organizations use Ethernet protocol to streamline their network connectivity, but it may come with the following drawbacks:

• Limited distance and mobility: Ethernet networks are generally designed for localized areas, which limits their range in large industrial settings. As the distance between devices increases, interference also increases, negatively affecting the network's performance and dependability.
• Higher communication latency: Though it can be used for real-time communication, Ethernet struggles to meet the time-sensitive demands of interactive applications. It's susceptible to communication delays and higher jitter occurrence, which can lead to data loss.
• Bandwidth constraints: Ethernet's available bandwidth decreases as network traffic increases, causing slower speeds and data congestion. This becomes a challenge in high-traffic settings with many computers, reducing network efficiency.
• Cable and troubleshooting challenges: Ethernet networks that use long cables can create crosstalk — electromagnetic interference causing signal interruption between network cables. Detecting problems in Ethernet networks can be challenging, specifically when isolating damaged cables or nodes. 

Consult with Astrodyne TDI for the Right Technology

Receive expert guidance on Ethernet and EtherCAT protocols, and reach out to Astrodyne TDI. Our experienced team will help you determine the best network solution for your needs. We provide superior engineering support for various fields, including medical, military, and aerospace applications. Trust us to offer tailored advice to help you choose the most effective network application to streamline your operations. 

For over 60 years, Astrodyne TDI has provided superior-quality power supplies and EMI filters for a diverse array of markets and industries. We also offer custom power supplies and EMI filters with advanced tools and technology. Contact us to request an online quote today.