How to choose PLC and MCU?

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* Experience sharing *

Recently, many students always ask me PLC And how to choose SCM ？

therefore , Today I put myself Experience sharing For everyone .

A dozen years ago , I also faced such a choice when I was in school , I simply learned it all by myself .

* SCM and plc The difference between *

First of all , SCM is a chip , You can't use it alone . and PLC It is a general controller composed of single chip microcomputer , You can use it directly .

Use SCM to control , Need auxiliary circuits , Like crystal vibration , Reset , Power Supply , Input and output circuits , Besides programming , And make your own circuit board , Professional knowledge is also required , Inconvenient to use

second , The programming of the two is different , SCM programming requires assembly language or C Language , It will be more difficult .PLC The system program is solidified internally , Just use the corresponding programming language , Easy to learn , So programming is relatively simple .

Third ,PLC It is a general controller mainly composed of single chip microcomputer , So in terms of price ,PLC It's much more expensive than MCU . Meter , Household appliances and other functions are fixed , Large quantity of products are suitable for single chip computers , And those industrial controls with large functional differences are suitable for PLC.

Make one SCM products , Long cycle , So it is suitable for fixed functions , High volume products . Make one PLC Our product cycle is relatively short , The application is flexible . therefore PLC Suitable for industrial control in different occasions

* Which is easy to learn ? *

I believe most beginners , Most concerned issues , SCM and PLC Which is easy to learn

Single chip microcomputer is a microcomputer system , It belongs to one of the microcontrollers ,PLC The full name of is programmable logic controller , From the name, the two must have something in common , But there are essential differences .

It's still easy to learn about MCU PLC Studious questions , On the whole ,PLC Because it's easy to get started , So it is more suitable for novices , Easier to get started , Words alone are no proof , Let's see why .

The function of single chip microcomputer is better than PLC Powerful , But the stronger the function, the more extensive , It means that the circuit will also be very complex , MCU programming language C Language or assembly language compared to ladder diagram , It's not so easy to understand .

To make a long story short , Want to learn SCM , You not only have to have a computer hardware foundation . I have to C Language programming , And you should also know more about the circuit .

* Their strengths and weaknesses *

Next, it analyzes the MCU and PLC Advantages and disadvantages of .

1、 programing language

PLC Our programming languages are ： Ladder diagram language （LD）、 Instruction list language （IL）、 Functional module diagram language （FBD）、 Sequential function flow chart language （SFC）、 Structured text language （ST）.

It can be said that ladder diagram is the most used , Because it is a bit like the relationship between relay coil and electric shock action in electrical control , If you have learned relay - If the contactor is controlled , It's much easier to get started , So many electrical controllers choose it , It will also be easier for beginners to program with ladder diagram .

The programming language of MCU is C Language or assembly language , It also adopts its own programming language , such as 51 Single chip microcomputer ASM Language ）.

There are many and complex single-chip instruction codes , So programming is more difficult , Especially when it comes to more complex projects, the process will be more difficult , Because we should not only understand English , And understand the number system , People who have a computer foundation may be better .

2、 Hardware

The price of single chip microcomputer is generally low , As can be seen from the picture , Its peripheral input 、 There are many outputs . And the control circuit of single chip microcomputer needs to be set by the user .

PLC It looks very simple , Because of its interface 、 Power Supply 、 Anti interference circuits are designed in PLC Inside , Therefore, when learning and operating , Less time and energy are spent on the circuit , The main focus is to learn to use ladder diagram to control each output port , Ladder diagram for beginners , Often easy to use . And adding an extension module can realize other functions , but PLC The price of is more expensive than MCU .

3、 Application field

Field ratio of single chip microcomputer PLC wide , It can be widely used in instruments 、 Household appliances 、 Medical equipment 、 Aerospace 、 Intelligent management and process control of special equipment , High technology content , Flexible use , But the workload is large , anti-interference 、 Low modularity requirements . Develop consumer electronics 、 Electronics for commercial applications 、 toy 、 Home appliances, etc. can choose SCM .

But you should know that SCM is just a chip , So the circuit is more complicated , Beginners often face weak anti-interference ability , Now the signal is distorted , The problem of too much interference . But it's not a problem for experienced people .

* Respective fields *

Many people say that MCU can replace... In the industrial field PLC, I can only say that in industry , Most large-scale automatic control equipment still need to use PLC To complete .

relative PLC, MCU development is closer to the bottom , Because MCU is just a chip , Need to rely on peripheral circuits + The program can form a complete product .

therefore Development is more difficult than plc It's much bigger. , However, the development space of single chip microcomputer is more than plc It's much bigger. .

At the beginning of the design ,PLC It pays more attention to industrial applications , For anti-interference 、 Device interface 、 Connected to the Internet 、 Modularization has perfect technical support , Easy to use , Short development and design cycle . for example , automatic production line , It has to be used. PLC To do it . SCM can only be used to develop some supplementary equipment .

To make a long story short PLC Simpler than MCU , Easier to use . SCM has a wider range of knowledge , complex , But it is also widely used .

If you study on your own Plc, Someone with someone taught on SCM . It is suggested to learn SCM first ,plc Naturally ！

Speak really ,PLC Compared with the advantages of SCM , There are no more and more advantages , There are problems in all aspects , MCU replaces plc, It can be said that it is the general trend ！

In a large automated semiconductor factory ,PLC It has become a transfer of data collection closer to the execution end , Has long lost control .

The small panel can be used PLC, however , Large size panel factory or wafer factory ,PLC Almost no one used it ！

PLC Now there are four main disadvantages , The analysis is as follows

（1） Large visual image processing end , Not anymore PLC What you can do .

（2） With the popularity of embedded development , Continuous technological innovation , There are more and more SCM practitioners , There are almost no thresholds , Graduates of a related major are basically competent in the programming of single chip microcomputer system . As long as you want to learn , No one can't learn SCM ！ therefore , Most people who want to get a high salary will choose SCM ！

（3） The cost has always been plc The disadvantages of , A low-end domestic PLC The price is about 300, And you can at least buy SCM in a treasure STM32.

（4） Adaptation to harsh environments , In the harsh electromagnetic environment , Many companies have chosen SCM as a substitute ,

Only the machine room with worse environment , Around large motors , Is true PLC Where you can stay , These are PLC Development for decades is irreplaceable .

therefore ,plc The road will be narrower and narrower , Last , Go to the corner where only it can survive , And others disdain its little cake .

PLC The scope of application is too narrow and Limited , Learning SCM can better play their creativity , ha-ha , As a young man, I'd better challenge myself , Choose SCM to enter embedded , The future is bright , The road is winding .

Get... Free of charge , Introduction to single chip microcomputer to advanced learning Introduction ( Tutorial attached + Tools )https://blog.csdn.net/HWdanpianji/article/details/121722883?spm=1001.2014.3001.5502

You want to learn SCM , Review introductory materials , You can get the information from me