Using a microcontroller for control requires auxiliary circuits,such as crystal oscillator,reset,power supply,input and output circuits.In addition to programming,you also need to make your own circuit board,which requires professional knowledge and is inconvenient to use.
Second,the programming of the two is different.Microcontroller programming requires assembly language or C language,which is more difficult.The system program is solidified inside the PLC,and you only need to use the corresponding programming language.It is easy to learn,so programming is relatively simple.
Third,PLC is a general-purpose controller mainly composed of microcontrollers,so in terms of price,PLC is more expensive than microcontrollers.
Products with fixed functions and large quantities such as instruments and home appliances are suitable for single-chip microcomputer,while those industrial controls with widely different functions are suitable for PLC.
The cycle of making a single-chip microcomputer product is relatively long,so it is suitable for products with fixed functions and large quantities.The product cycle of making a PLC is relatively short and the application is relatively flexible.Therefore,PLC is suitable for industrial control in different situations.
4.Scalability and communication capabilities
MCU:The scalability of MCU is relatively limited,and it mainly connects peripherals such as sensors and memory through external buses(such as I2C,SPI,UART,etc.).Although functions can be added by designing expansion boards or modules,this process often requires customized development,which increases the complexity and cost of the system.
PLC:The modular design of PLC gives it good scalability.Users can add or replace I/O modules,communication modules,etc.according to actual needs to achieve flexible expansion of functions.PLC also supports a variety of industrial communication protocols(such as Modbus,Profinet,EtherNet/IP,etc.),which is convenient for data exchange and integration with other devices or systems,and is an important part of building large-scale automation control systems.
Advantages and disadvantages of PLC and MCU:
1.Programming language
PLC programming languagesinclude:ladder diagram language(LD),instruction list language(IL),function block diagram language(FBD),sequential function flow chart language(SFC),structured text language(ST).
It can be said that ladder diagram is the most widely used,because it is a bit like the relationship between relay coil and electric shock action in electrical control.If you have learned relay-contactor control,it is much easier to get started,so many electrical control personnel choose it,and it is easier for novices to program with ladder diagram.
The programming language of MCU is C language or assembly language,and it also uses its own programming language,such as ASM language of 51 MCU).
MCU instruction codes are many and complex,so programming is more difficult,especially when it comes to more complex project programs,because not only English but also number system must be understood.People with computer basics may be better.
2.Hardware
MCU is generally low-priced,and its peripheral input and output are relatively large.And the control circuit of MCU needs to be set by the user.
The appearance of PLC looks very simple,because its interface,power supply,and anti-interference circuit are all designed inside the PLC,so when learning and operating,less time and energy is spent on the circuit.The main focus is to learn to use ladder diagrams to control each output port.Ladder diagrams are often easy to use for novices.And adding expansion modules can achieve other functions,but the price of PLC is more expensive than that of single-chip microcomputers.
Single-chip microcomputers and PLCs can be used in the fields of intelligent management and process control of instruments and meters,household appliances,medical equipment,aerospace,and special equipment.Single-chip microcomputers can be selected for the development of consumer electronics,electronics,toys,and household appliances for commercial applications.PLCs can be selected in the fields of industry and agriculture.
Secondly,the single-chip microcomputer is just a chip,so the circuit is relatively complex.Beginners often face problems such as weak anti-interference ability,signal distortion,and excessive interference.PLC will not.
The above is about the difference between PLC and MCU.As a PLC manufacturer with more than 20 years of experience,Unimat's PLC can seamlessly integrate with Siemens PLC,is affordable,and supports a three-year warranty.If you have PLC needs,please contact us.
