June 10th, 2019 by
Ethernet is an amazing standard that beat out other topologies like Token Ring long ago. But the better part of the standard is how it is being innovated today with new protocols that re-use the hardware components that Ethernet created. Because Ethernet is NOT deterministic, it cannot be used in many real-time or deterministic applications. This is especially true for machine automation software or motion control applications. However, even though the Ethernet protocol cannot be used for motion control applications, the hardware like the TCP NIC card or the CAT5 Cable can be used. It is especially powerful when the protocol is deployed on a PC with Windows that has been transformed into an Real Time Operating System (RTOS).
And there is good reason to reuse this hardware: COST SAVINGS. The average cost per linear foot of proprietary motion control cables in a machine setting exceeds $10 and sometimes is higher than $30/linear foot. By contrast, the cost per linear foot for a TCP CAT5 cable is pennies. With the cost difference so low, many companies have introduced new protocols and standard fieldbuses that reuse the Ethernet hardware but simply use a different protocol.
In motion control and machine automation applications like CNC or Robotics, new protocols like EtherCAT, Profinet IRT, Sercos, or Powerlink are utilized to guarantee determinism over alternative standard Ethernet hardware. The Ethernet protocol is replaced by the motion control fieldbus protocol like EtherCAT.
Given its networking demands and digitization focus, Industry 4.0 demands a standard, widely accepted digital field bus that reuses the Ethernet hardware. While there are many proprietary digital fieldbus solutions and some high performing, “open” digital fieldbus standards, EtherCAT stands alone as the most widely accepted standard for digital fieldbuses. Quite simply, it is the safest and best choice for an Industry 4.0 implementation. By the way, EtherCAT stands for (Ethernet for Control Automation) is a real time Ethernet protocol that is mainly applied in process and factory automation. The market prefers EtherCAT over all other fieldbus protocols because it is supported by the largest number of motion control and servo drive manufacturers.
In terms of performance and determinism, the closest competing fieldbuses to EtherCAT include PROFINET and Sercos III. Both standards deliver the requisite determinism and deliver the highest quality, but they do so at a premium price. The main issue that drive prices higher is that there are only a dozen servo drive manufacturers have embraced either standard whereas hundreds of servo drive manufacturers have embraced EtherCAT. Having more choice drives the standard forward and lowers prices. A standard is proportionally more effective as the percentage of the vendors in the market embrace it. Hands down, EtherCAT has the best adoption in the market when measured by the number of servo drive vendors that support it.
EtherCAT demands real time precision and more and more companies are moving their hardware-based real-time control systems to Industrial PCs (IPC) that has Windows and a real time operating system (RTOS) on that PC. Windows eases integration and usability with powerful HMIs (Human Machine Interface) and the RTOS delivers the precision and determism.
EtherCAT is an open technology that repurposes low-cost Ethernet hardware by adding a new protocol that enables real-time, deterministic communications, which is required for precision motion control applications. As such, RTOS platform on a PC with EtherCAT paves way for utilization of a single integrated development platform that maximizing machine performance and establishes a machine automation software platform to insure the machine will be able to participate in Internet of Things (IOT) and Industry 4.0 initiatives.