In the early automation industry, motion control was mostly pulse control and analog control. Later, CANopen was developed, and various Ethernet buses emerged, such as EtherCAT, PROFINET, POWERLINK, SercosIII, RTEX, and so on.
Why is EtherCAT developing so rapidly both globally and in China now, mainly reflected in the following five points:
1. The leading edge of EtherCAT technology:
The EtherCAT protocol processing is entirely carried out in hardware, and the protocol ASIC can be flexibly configured, greatly improving work efficiency. The refresh cycle for 1000 distributed I/O data is only 30 μ s. This includes terminal cycle time. Communication with 100 servo axes only requires 100 μ S. During this period, setting values and control data can be provided to all axes, and their actual positions and states can be reported. By utilizing the excellent performance of EtherCAT technology, control methods that cannot be achieved with traditional fieldbus systems can be achieved.
The ZMC464 motion controller with positive motion technology has been tested to operate with 16 axis EtherCAT servo for 100us and 64 axis EtherCAT servo for 500us.
2. The Openness of EtherCAT Technology:
EtherCAT (Ethernet Control Automation Technology) is an open architecture fieldbus system based on Ethernet, which complies with IEC specifications (IEC/PAS 62407) and is also a national standard.
There are a large number of EtherCAT master and EtherCAT slave devices and products in the market.
There are many professional third-party companies both domestically and internationally that provide technical consulting and services for EtherCAT.
In terms of EtherCAT chips, mainstream FPGA manufacturers Altera and Xilinx support EtherCAT master-slave solutions. Major semiconductor manufacturers also support the EtherCAT protocol, such as TI, Infineon, microchip, and other semiconductor manufacturers that support EtherCAT slave chips. Of course, Beifu Company also provides EtherCAT interface chips such as ET1100 and ET1200.
3. The promotion of ETG Global Organization and ETG China Organization:
ETG Global has 5 regional organizations worldwide, with 5205 member units as of 2018.
The preferred industrial Ethernet communication interface for domestic servo drive manufacturers and stepper drive manufacturers is EtherCAT. There are hundreds of domestic manufacturers that support EtherCAT servo drives and EtherCAT IO modules.
4. Combining the advantages of EtherCAT bus motion control in practical on-site applications:
a. The electrical cabinet wiring of the system is very convenient as long as the network cable is connected between nodes;
b. The system has strong anti-interference ability, and the network interface is isolated. The EMC characteristics of the entire electrical system are good;
c. Once EtherCAT initialization is completed, it is possible to directly read the multi turn absolute encoder positions of all axes;
d. SDO can read and modify the parameters and gains of each axis online, making axis parameter debugging more convenient;
e. By selecting different PDO data contents, torque amplitude limitation can be achieved under position control, speed limitation under torque control, and CSP (periodic position)/CSV (periodic speed)/CST (periodic torque) can be freely switched;
f. Convenient for remote diagnosis and maintenance of electrical systems on the upper computer, and more convenient for predictive maintenance.
5. It is possible to simulate and debug a motion control system without an actual motion controller:
Virtual simulation and debugging have become increasingly necessary in the industrial automation industry. Firstly, software can be debugged before the equipment is ready, and secondly, the efficiency of development and debugging can be further improved.
