(1) Central Processing Unit (CPU) The central processing unit (CPU) is the control center of the PLC. It accepts and stores user programs and data typed from the programmer, checks the status of the power supply, memory, I/O and alert timer in accordance with the functions assigned by the PLC system program, ...

1. The ladder diagram language is the most commonly used programming language in PLC programming. The CPU reads physical input into a memory table, often referred to as an "input table". The form is evaluated for use in the procedure. Different platforms, using different types of registers; In each scan cycle, follow from left to right, ...

The first is relay output, the relay output response speed is slow, the output current is large, generally can reach 2A, but the electric shock life is short, the output frequency is low, the maximum is 1HZ; The second is transistor output, the transistor output response speed is fast, the output current is small, and the contact life is relatively small.

1. Power components The power supply assembly is used to provide the power required for the operation of the PLC, and the external power supply can be converted into a power supply for the PLC internal and applicable to the case. 2. Microprocessor CPU and memory components Microprocessor CPU is the core device of PLC, and CPU is different from each manufacturer.

1. Input processing Input processing is also called input sampling. In this phase, the through-end state of all input terminals is read sequentially, and the read information is stored in the corresponding image register in memory. Here the input image register is flushed. Then the program execution phase begins. In the execution of the procedure ...

1. The PLC adopts the mode of centralized sampling and centralized output, which can reduce the influence of external interference. 2. The working process of PLC is the process of cyclic scanning. The duration of the cyclic scan depends on the speed of execution of the instructions and the length of the user's program. 3. Output to input ...

1. Common processing: reset the monitoring timer, perform hardware checks, user memory checks, etc. 2. Program execution: The CPU interprets and executes each instruction in the order of first left and then right, first up and then down, and reads out each relay according to the input image register and the component image register.

(1) The PLC adopts the working mode of centralized sampling and centralized output, which reduces the influence of external interference. (2) The working process of PLC is the process of cyclic scanning, and the length of cyclic scanning time depends on the speed of instruction execution, the length of the user program and other factors. (3) Output ...

Peripheral circuit component failure This type of failure often occurs in the failure of the PLC after a certain period of work. In the PLC control loop, if there is a component damage fault, the PLC control system will immediately and automatically stop working. The input circuit is PLC to accept switching quantities, analog quantities, etc.

1. The meaning of the representation is different: PLC is the abbreviation of planar optical waveguide (technology), the so-called planar optical waveguide, means that the optical waveguide is located in a plane. A servo control system is a feedback control system used to accurately follow or reproduce a certain process.

The first is that the PLC sends a start/stop signal to the server through the I/O point, and the server controls the operation of the servo motor. The PLC controls the operation/stop of the servo through the digital output, so as to achieve the purpose of controlling the servo motor. The second is through the pulse output of the PLC, which ...

The PLC communicates with the host computer, and BlandC is used to write the communication program between the host and the PLC, and the COM1 port must be initialized, the baud rate is 9600bps, and the parity check bit adopts even check, and the seven-digit valid data is used. When the computer receives the response character ACK from the PLC, it ...

1. In this computer, right-click, manage, check to find the device manager, plug in the USB-PPI cable (one end is connected to the computer, the other end is connected to the PLC), the computer device manager will pop up the port USB-SERLAL CH304 (com3), the number in parentheses may change, indicating that you have found the cable. This...

1. Application field: The initial design goal of PLC is only to replace complex relay circuits, and DDC is originally only used in industrial automation instruments: PLC emphasizes versatility, DDC emphasizes specificity: PLC is used in the field of industrial control, and DDC is used in professional building systems. 2. Structural differences ...

1. The role is different A PLC (Programmable Logic Controller) is an electronic system designed for digital operations in an industrial environment. The inverter is the application of frequency conversion technology and microelectronics technology to control the AC motor by changing the frequency of the motor working power supply.

1. PLC is a relatively mature control system composed of single-chip microcomputer, which is the product of a mature and stable single-chip microcomputer application system that has been debugged. It is highly versatile. 2. The single-chip microcomputer can form a variety of application systems, and the application range is wider. In the case of a single "microcontroller", it ...

Installation: The installation mode of PLC system is divided into centralized, remote I/O and distributed with multiple PLC networking. Centralized does not need to set up the drive remote I/O hardware, the system response is fast, and the cost is low; Remote I/O is suitable for large systems with a range of ...

Open-loop control Open-loop control of switching quantity is the most basic control function of PLC. The instruction system of PLC has powerful logic operation ability, and it is easy to realize various logic control methods such as timing, counting, and sequential (stepping). Most PLCs are used to replace traditional relay contactors...

In the manufacturing industry, there are a large number of open-loop sequential control based on switching quantities, which carries out sequential action numbers according to logical conditions and operates in chronological order; In addition, there is the control of chain protection actions according to the logical relationship that is not related to the sequence and timing; As well as a large number of switching quantities, pulse quantities, gauges...

1. Correctness (low debugging cost) First of all, the PLC program must be able to work correctly to meet the requirements of the actual control process. This is the essence of the PLC program, and if you don't do that, nothing else makes sense. 2. Reliability (low maintenance cost) Not only to ...

1. After connecting the wires according to the wiring diagram, start the power supply and prepare to set the parameters of the inverter. 2. Press the "MODE" button to enter the parameter setting mode, and set the Pr.79 to "2": external operation mode, the start signal is input by the external terminal (STF, STR), and the speed adjustment is carried out by the external terminal.