Author: Fraser Gordon, IOTech Software Engineer | IOTech
One of our biggest strengths at IOTech is our rapidly growing set of southbound device connectors for the Edge. Built for Edge Xpert, our commercial implementation of the open source EdgeX Foundry platform, these Device Service connectors cover a wide array of protocols. I helped to design and implement one of the latest additions - an EtherCAT Master Device Service.
EtherCAT stands for Ethernet for Control Automation Technology. It is a fieldbus protocol implementing a master/slave architecture over Ethernet where a packet is transmitted by the master at a user-configurable cycle time. It adopts a unique approach where the packet is not fully processed by each slave individually, but rather as the packet travels through each slave, only data meant for that individual slave is taken, and output data from the slave is written to the packet. This on-the-fly processing and its distributed clock mechanism allow EtherCAT to achieve high data rates, low latency and synchronised output actions.
Due to its high performance and flexibility, EtherCAT is very popular within industrial automation environments. The specific sectors can range from semiconductor manufacturing to packaging machines. There are many EtherCAT slave devices offering functionality for a whole host of tasks such as stepper motor drives and current measurement terminals.
With an EtherCAT Master Device Service now available, EtherCAT slaves can be integrated into Edge Xpert allowing for local processing and control to be performed. Edge Xpert can run multiple Device Services at a time, so the EtherCAT data can be normalized and aggregated along with Modbus, OPC UA and PROFINET data, for example. You can run edge analytics over that data or push it northbound to a Cloud service of your choice. Our EtherCAT Device Service has a range of configurable options including setting the cycle time and a choice of three different synchronization modes for each slave - SM-Synchronous, DC Sync0 and DC Sync1.
On a personal level, developing this Device Service has been an enjoyable task. It’s been technically challenging, and I’ve gained a deeper understanding of EtherCAT and utilised C programming skills learnt at University. With the rapid pace that “Industry 4.0” is growing, it’s great to see open platforms like the EdgeX Foundry and Edge Xpert gaining so much traction. They negate the requirement for point solutions and vendor lock-in and foster collaboration between many different companies, teams and people.
Take a look at the EtherCAT Device Service demo video we put together showing how Edge Xpert can drive the Beckhoff stepper motor and a pair of Infineon dev boards we set up in our lab.
It would be great to hear feedback as people use the EtherCAT Device Service and let us know any questions.