What is PLC? PLC is an English abbreviation, its full name is Programmable Logical  Controller, which means programmable logic controller, PLC is the first letter of this string of  English words. In addition, let's understand PLC from the following aspects:  

What is PLC? PLC is an English abbreviation, its full name is Programmable Logical  Controller, which means programmable logic controller, PLC is the first letter of this string of  English words.  In addition, we understand PLC from the following aspects:  

1. The appearance of PLC. What does the appearance of PLC look like? Different varieties  of PLC have different shapes.  

The following figure shows the Siemens CPU300 series PLCs, which are now recognized  as more mainstream in the world, as shown in the figure below:  

The following picture shows the Siemens CPU200 series PLC:

The following picture shows the domestic Delta series PLCs:

Of course, there are many varieties, such as the Mitsubishi series, the Omron series, the  Yonghong series, etc., which will not be listed here.  

2. What is the working principle of PLC? How does it work? 

 We can understand it as a brain that controls the automated production line, and this  brain CPU has input terminals for collecting signals and output terminals for issuing  instructions. Between input and output, this CPU goes through a series of instruction  operations, of course, according to the logic operation according to the program we wrote,  and the logical signal is output to the output terminal for 24V signal output, output to  external circuits such as relays, and then control the actuator components such as cylinders  and motors.  

As shown below, a CPU with input and output terminals:  

We all know that computer operations are composed of 0 and 1, and the PLC CPU here  is also understandable, which can be understood as the number 1 at the input and output  side represents a 24V weak signal, and O represents no signal.  

3. Why use PLC control?  

Let me give you an example, take a small project I took IO years ago as an example. The  picture below shows the traditional relay circuit before the modification (the camera  equipment at that time was not very clear).  

The picture above is the traditional relay control. Doesn't it look miserable?

Let's take a look at the picture below, which is a circuit system controlled by PLC. Isn't it neat and refreshin ? he camera ui ment at that timewas not ve clear

Through the above comparison, it is not difficult to see that the circuit using the PLC  control system is simple, the follow-up maintenance and repair work is very convenient, and  the work is stable, the failure rate is low, the space occupied is small, and it can complete a  lot of intelligent work ....... The trend to replace artificial labor. 

In short, PLC control mode is an inevitable trend of automated intelligent production,  which saves a lot of costs for integrated modern production. At the same time, learning PLC  technology is also a necessary part of our workplace promotion and salary increase.  

Friends, I hope this article will help you make progress.