The Roles TSN and EtherCAT Play in Leading Machine Automation and Work Cell Applications

Many customers ask what roles EtherCAT and Time-Sensitive Networking (TSN) play when building a machine controller with the KINGSTAR machine automation platform.

First, understand that TSN and EtherCAT are two technologies that are transforming the world of industrial automation.

TSN is a set of standards developed by the IEEE to provide deterministic and reliable communication in industrial and automotive networks. EtherCAT has become the most widely adopted fieldbus and is a high-speed industrial Ethernet protocol that is widely used for motion control applications.

Typically, TSN is used to deliver these communications BETWEEN high precision machines and controllers. TSN is really just a transport layer and often carries the traffic of protocols such as EtherCAT, ccLink, Mechatrolink, Profinet, Profibus, and Modbus to name a few. EtherCAT is mostly used to control the servos and I/O INSIDE a high-precision machine. Together, these technologies enable real-time communication and precise control in industrial automation systems in a work cell.

For example, here is a functional breakdown of how communication works between a Cobot-Load and Unload operation on a CNC machine and the roles that TSN and EtherCAT might play. Overall, the EtherCAT would be used inside the controller of the Cobots and the CNC machine and there are critical communications that would be handled by TSN. Here are a few points for this load and unload example.

For Loading and unloading: The robot which is powered by an EtherCAT fieldbus is responsible for loading and unloading workpieces from the CNC machine, also powered by a fieldbus and this means the protocol would be EtherCAT. For that, the robot requires information about the CNC machine’s state, for instance, whether the machine is ready to receive a workpiece for machining or it has already finished machining a workpiece. This type of communication is done with the help of TSN.

Synchronization: The robot and CNC machine need to be synchronized to ensure that they move together in a coordinated manner. Since this is communication between machines, TSN would be the appropriate coordinating network. This is important for optimizing cycle times and improving overall system performance. To achieve this, the robot and CNC machine need to exchange information about their current position, velocity, and acceleration deterministically or in hard real-time.

Control signals: The CNC machine needs to send control signals to the robot to specify the position and orientation of the workpiece in the CNC machine’s work envelope. The robot receives this information to accurately position the workpiece for loading and unloading.

Data from sensors: In many cases, the robot might need to transmit sensor data to the CNC machine. This data could be dimension-related information or workpiece orientation. This type of data is useful for CNC machining in optimizing machining parameters and guaranteeing top-quality machining.

Quality of service: Different types of traffic, such as control signals and sensor data, may require different levels of quality of service (QoS). For example, control signals may need to be delivered with low latency and high reliability, while sensor data may be more tolerant of latency and packet loss.

Overall, communication between a CNC machine and a robot is critical for the efficient and accurate loading and unloading of workpieces, as well as for synchronization and coordination of motion. To achieve these goals, the communication system needs to provide reliable and timely transfer of control signals and sensor data, as well as appropriate QoS guarantees. A combination of EtherCAT for real-time communication inside the machine and TSN communication between machines offers the ideal architecture.

KINGSTAR Fieldbus powered by EtherCAT allows the communication between the controller and multiple points to be connected at the same time. Based on RTX64, this Fieldbus EtherCAT Master stack not only supports but also simplifies EtherCAT network configuration and development, enabling you to achieve the highest precision and deterministic precision.