What are the differences between motion controller and plc

What are the differences between motion controller and plc?

Motion controller is a special controller to control the operation mode of the motor: for example, the motor is controlled by the AC contactor by the travel switch and the motor drives the object to run up to the specified position and then run down, or use the time relay to control the motor to turn positive and negative or turn for a while to stop and then turn for a while to stop. The application of motion control in the field of robots and CNC machine tools is more complex than that in specialized machines, which have a simpler form of motion and are often referred to as general motion control (GMC).

Features of motion controller:

(1) The hardware composition is simple, insert the motion controller into the PC bus, connect the signal line can be composed of the system;

(2) Can use the PC has rich software development;

(3) The code of motion control software has good universality and portability; 

(4) There are more engineers who can carry out development work, and development can be carried out without much training. 

What is a plc?

Programmable logic controller (PLC) is a digital arithmetic operation electronic system designed for application in industrial environment. It uses a programmable memory in which the instructions to perform operations such as logical operations, sequence control, timing, counting and arithmetic operations are stored, and various types of mechanical equipment or production processes are controlled through digital or analog input and output.

Characteristics of plc

(1) High reliability. Because PLC mostly uses single chip microcomputer, so high integration, coupled with the corresponding protection circuit and self-diagnosis function, improve the reliability of the system.

(2) Easy programming. PLC programming uses relay control ladder diagram and command statement, the number is much less than the microcomputer instruction, in addition to the middle and high grade PLC, the general small PLC only about 16. Because of the ladder diagram image and simple, so easy to master, easy to use, even do not need computer expertise, can be programmed.

(3) Flexible configuration. Because PLC adopts the building block structure, the user only needs to simply combine, then can flexibly change the function and scale of the control system, therefore, can be applied to any control system.

(4) Complete input/output function modules. One of the biggest advantages of PLC is that for different field signals (such as DC or AC, switching quantity, digital quantity or analog quantity, voltage or current, etc.), there are corresponding templates can be connected with industrial field devices (such as buttons, switches, sensing current transmitters, motor starters or control valves, etc.) directly, and connected with the CPU motherboard through the bus. 

(5) Easy installation. Compared with the computer system, the installation of PLC does not need a special room, nor does it need strict shielding measures. When used, only the detection device and the I/O interface terminal of the actuator and PLC are connected correctly, then it can work normally.

(6) Fast running speed. Because PLC control is controlled by the program execution, so whether its reliability or running speed, is the relay logic control can not be compared. In recent years, the use of microprocessor, especially with the large number of single chip microcomputer, greatly enhanced the ability of PLC, and the difference between PLC and microcomputer control system is becoming smaller and smaller, especially the high-grade PLC is so.

 The difference between motion controller and plc:

Motion control mainly involves the control of stepper motor and servo motor. The control structure is generally: control device + driver + (stepper or servo) motor.

The control device can be PLC system, can also be a special automatic device (such as motion controller, motion control card). PLC system as a control device, although has the flexibility of PLC system, a certain versatility, but for high precision, such as – interpolation control, sensitive requirements when it is difficult to do or programming is very difficult, and the cost may be high.

With technological progress and accumulation, motion controller emerges at the right moment. It solidifies some general and special motion control functions in it — such as interpolation instructions. Users only need to configure and call these functional blocks or instructions, which reduces programming difficulty and has advantages in performance and cost.

It can also be understood that the use of PLC is a common motion control device. Motion controller is a special PLC, full – time for motion control.