I. Differences between motion controllers and PLCs
1. Motion controller
The application of motion control in the fields of robotics and CNC machine tools is more complex than its application in specialized machines, because the latter have simpler motion patterns and are often referred to as general motion control (GMC).
2. PLC
A programmable logic controller (PLC) is a digital electronic system specifically designed for industrial applications. It employs a programmable memory that stores instructions for performing logical operations, sequential control, timing, counting, and arithmetic operations, controlling various types of machinery or production processes through digital or analog inputs and outputs.
3. Differences between motion controllers and PLCs
Motion control mainly involves the control of stepper motors and servo motors. The control structure is generally: control device + driver + (stepper or servo) motor.
The control device can be a PLC system or a dedicated automation device (such as a motion controller or motion control card). When a PLC system is used as a control device, although it has the flexibility and certain versatility of a PLC system, it is difficult to achieve high precision, such as interpolation control, and requires sensitive response, or programming is very difficult, and the cost may be high.
With technological advancements and accumulated expertise, motion controllers have emerged, embedding some common and specialized motion control functions—such as interpolation instructions. Users only need to configure and call these function blocks or instructions, thus reducing programming difficulty and offering advantages in performance and cost.
Alternatively, it can be understood as follows: a PLC is used as a common motion control device. A motion controller is a special type of PLC, specifically designed for motion control.
II. Development Trends of Motion Controllers
Driven by strong demand for motion controllers from downstream machinery manufacturers, the Chinese general-purpose motion controller (GMC) market is expected to reach US$1.065 billion in 2014, while the CNC motion controller market is expected to reach US$1.239 billion.
Experts believe that the machine tool, textile machinery, rubber and plastics machinery, printing machinery, and packaging machinery industries account for over 80% of the sales revenue of China's motion control market, and will remain the main markets for motion controllers now and in the future. Meanwhile, the demand for motion controllers from the food and beverage machinery, tobacco machinery, medical equipment, and scientific research equipment industries is also steadily increasing due to their close connection to people's lives and the consistent growth in these end-consumer sectors.
Although the electronics and semiconductor machinery industry suffered some setbacks at the end of 2008, the application of motion controllers in electronics and semiconductor machinery has been growing. In 2009 and 2010, driven by substantial capital investment in electronics manufacturing and strong end-consumer demand, sales of motion controllers in electronics and semiconductor machinery rebounded strongly. As one of the world's most important electronics manufacturing bases, China is experiencing stable growth in both demand and output for electronics manufacturing, electronics assembly, and semiconductor equipment. These industries are unlikely to relocate on a large scale to other countries with lower costs for a considerable period. Therefore, sales of motion controllers in the electronics and semiconductor machinery industry are expected to maintain rapid growth in the coming years.
As mechanical manufacturing OEMs become increasingly familiar with motion controller products, motion controllers have been expanding their application areas and scope, achieving breakthroughs in some non-traditional niche industries. Although these industries only account for a small portion of the motion controller market, these areas are poised to become future profit growth drivers and provide market opportunities for many small and medium-sized companies. Examples include wind turbine pitch control systems, oilfield pumping units, flame cutting machines, silicon wafer cutting machines, solar tracking systems, spring machines, and flocking machines.
