PLC related knowledge, PLC basic knowledge

The basics of PLC are as follows:1. It is necessary to master a certain electrical foundation: master the use of commonly used devices such as sensors, proximity switches, encoders and the working principle of contactors.

2. Master the basic knowledge of computer: familiar with the installation of various software and the setting of network communication.

3. Counters and timers should be assigned before use.

4. The expression of the logic function diagram basically follows the logic language of the "and", "or" and "not" gate circuits of the digital logic circuit, and is represented in the form of a logic block diagram.

5. The logical function diagram is used to describe the program, which is easy to describe the more complex control function, the expression is intuitive, and it is easy to check the error.

There are the following:

1. LD (take instructions).

The command that a NO contact is connected to the left busbar, and is used for every line of logic that starts with a NO contact.

2. LDI (Counter-Instruction).

A NC contact is connected to the left busbar command, which is used for every logic line that starts with a NC contact. LD and LDI instructions can be used to input the contacts connected to the left bus, and can also be used with ANB and ORB instructions to implement block logic operations.

3. LDP (take the rising edge instruction).

The rising edge detection command for the normally open contact connected to the left bus is applied only for one scan cycle when the rising edge of the specified bit element is turned on (by off on).

4. LDF (take the falling edge command).

Falling edge detection command of the normally closed contact connected to the left busbar. LDP and LDF commands are only turned on for one scan cycle when the corresponding component is active.

5. out (output command).

A command to drive a coil, also known as an output command.

The name of the programmable controller is BAI as a Programmable Logic Controller (PLC). Programmable DU controller is a digital shipment.

The electronic system of operation is designed for use in industrial environments.

Answer: It uses programmable memory to store instructions for performing logical operations, sequence control, timing, counting and arithmetic operations, and controls various types of machinery or production processes through digital and analog inputs and outputs. In terms of structure, PLC is divided into two types: fixed type and combined type (modular type). Fixed PLC includes CPU board, IO board, display panel, memory block, power supply, etc., which are combined into a non-detachable whole.

Modular PLCs include CPU modules, I-O modules, memory, power modules, backplanes, or racks, which can be configured in a combination according to certain rules.

PLC is called a programmable controller, which is mainly used for logic control, and it is composed of a microcomputer host and an input and output unit. The input and output are mainly switching signals, and now there are analog signals; The main principle is that the controller receives the input signal, calculates on the controller according to a certain logical relationship, and sends the output result to the output unit. For example, a school's bell machine can be realized with PLC, it has no input, only one output is connected to the switch of the electric bell, and the time program is used to control the start and stop of the electric bell.

8:00—8:01 Ring the bell means class, 8:

45-8:46 means that the class is over, and all the bells of the day and week can be put in at one time, and the bell can be automatically rang. This is just one of the simplest applications, which is mainly used to control the automation of various production processes such as chemicals, metallurgy, building materials, etc.

This information is not too much, you have to read it carefully by yourself.