With the rapid development of my country's social economy and the continuous improvement of its scientific level, people's pursuit of material life is constantly increasing, and the pace of socialist modernization is accelerating. As a result, all kinds of high-rise buildings have sprung up, becoming an important symbol of my country's rapid economic development. However, while the increasing height of buildings signifies the modernization of a city, it also brings many inconveniences to people and goods moving up and down stairs. Therefore, elevators have emerged. Since the first elevator was invented in the United States in 1887, elevators have solved the problem of vertical transportation between floors in high-rise buildings, enabling people to move quickly between buildings. High-quality, safe, and stable long-term operation is the most basic requirement for elevators. PLC-based elevator control systems are currently the most widely used elevator automation control systems, effectively solving potential safety issues related to the safe and efficient operation of elevators. Therefore, studying how PLCs control elevator automation is of great practical significance for understanding elevator safety performance and enhancing subsequent elevator maintenance and control.
The device, referred to as the PLC, is a complete core control system integrating communication technology, computer science, and automation technology. It interacts with peripheral circuits through data input/output ports, receiving input signals from external circuits and transmitting internal signals to peripheral circuits via these ports. This enables manual operation of the PLC and, through the logic calculation of machine code in its ROM, achieves logical control of other peripheral circuits.
Control systems based on PLC devices are very similar to those based on microcontrollers, but they differ significantly in other non-functional characteristics. First, PLC devices execute the code in the ROM repeatedly. Second, PLC devices have stronger stability than microcontrollers, and their anti-interference capabilities ensure long-term stable operation in harsh environments. Finally, PLC devices offer excellent cost-effectiveness and low power consumption.
The automated control of elevators using PLC devices is centered around a PLC. By constructing the PLC control system hardware circuit, it can communicate with peripheral circuits through data input/output ports. The core controller CPU of the PLC executes machine code burned into ROM, processes the data from the input/output ports, and then sends the processed data back to other peripheral circuits through the data input/output ports. This achieves automated elevator control using the PLC device. The figure shows the hardware design diagram for PLC-controlled automated elevator operation.
As shown in the diagram, the PLC device automates elevator control, requiring the cooperation of other peripheral circuits. These mainly include the car control panel, hall call panel, elevator speed control device, main drive control, door operator control, and safety devices. The speed control device and main drive control peripheral circuits are the power units that enable the elevator to operate at a predetermined speed and direction, thus driving the elevator car. The hall call panel is the device for receiving user input and signal output; users on each floor can use it to find out the current floor and request elevator use. The car control panel is the device for inputting request information and outputting status signals for controlling the car. The floor indicator is mainly a device for displaying the elevator's current floor status.
The PLC-based automated elevator control hardware design diagram illustrates the process of elevator operation. When a user requests elevator access via the call panel outside the hall, the device collects the request information and sends it to the PLC via its data input/output ports. The PLC's CPU executes the machine code in its ROM, identifies the request signal connected to the call panel, and then controls the speed control and main drive control devices to move the elevator to the requested floor, thus achieving automated elevator control. Similarly, when a user enters the elevator and operates the car control panel, the panel collects the corresponding signal and sends it to the PLC via its data input/output ports. The PLC's CPU executes the machine code in its ROM, identifies the request signal from the car control panel, and controls the door operator, elevator speed control, and main drive control devices to operate the elevator, thereby achieving automated control.
When writing the program, some details need to be considered. First, for the elevator speed control design, when the elevator moves from one floor to another, it needs to brake from a standstill, then accelerate to a certain speed, run at a constant speed for a period of time, and then decelerate until it stops. Second, for the car door operator control, after the door opens, infrared detection, thermal detection, and touch detection devices need to be used to detect the car door. If there is no signal input, the car door should be closed after a fixed time.
Summary: The automated control of elevators based on PLC devices mainly involves designing corresponding hardware structures according to different peripheral circuits, and then coordinating the hardware structure with electrical components. (Continued on page 59) (I) Intelligent Real-Time Control. Intelligent real-time control technology has been well applied in electronic system control. It can monitor power system data in real time and analyze the monitored data, then use certain methods to control based on the analysis conclusions. Strengthening intelligent real-time control technology on the basis of intelligent real-time control is essential to fundamentally improve the quality of power system control, enhance the control strength of the power system while ensuring quality, and reduce system risks based on the control strength. Intelligent real-time control technology has many advantages that previous technologies lack. It can use a graphical user interface to intuitively and effectively reflect power system data and operating status, avoiding the drawbacks of previous technologies, such as high failure rates and equipment resource losses. Intelligent real-time control technology has subtly become the dominant direction of current power system development.
(II. Artificial Intelligence Fault Diagnosis. Traditional power system fault diagnosis basically uses simple processing methods, only targeting simple processes, faults, and independent faults. The development of power systems requires more advanced technologies to replace these methods. The emergence of artificial intelligence fault diagnosis technology fills the gap in the previous ability to handle single processes, single faults, and independent faults. It can perform multi-process and comprehensive analysis of data parameters such as faults and anomalies, which can fundamentally diagnose faults and carry out corresponding quality control. Artificial intelligence (continued from page 7) National policy support. In terms of policy, in order to improve the utilization of small-scale cross-border e-commerce in bonded logistics centers, my country has added some new regulations. For example, companies can directly clear customs at the local customs bonded logistics center. Domestic goods entering the bonded logistics center can be treated as export goods and enjoy tax refunds. When foreign goods enter the bonded logistics center, customs grants them bonded status, and when goods in the bonded logistics center are sold domestically, companies can handle import customs clearance procedures. Goods in the bonded logistics center can be transported, stored, loaded, unloaded, and distributed between the company's bonded logistics center, bonded center, and bonded warehouse, enabling small-scale cross-border e-commerce in the bonded logistics center to have a longer development path.)
(II) Increasingly Convenient Transportation. In terms of transportation, many regions in my country, such as Fujian Province, Henan Province, and Shanghai, have established bonded logistics centers. These regions utilize various modes of transportation, including trains, sea, and air. Taking Pingtan in Fujian as an example, Pingtan has formed a comprehensive transportation system encompassing sea, road, and air. The first "Strait Ship" and "Lina Ship" opened a passage from Pingtan to Taiwan. Then, land transportation gradually improved with the Pingtan Bridge, and the highway from Yuxi to the Pingtan Second Bridge. Finally, the second cross-sea bridge in Pingtan extends all the way inland. After the "Twelfth Five-Year Plan" period, Pingtan will be included in the "one-hour economic circle," promoting the rapid development of cross-border e-commerce.
(III) Extension of the Industrial Chain. To improve the industrial linkages of the bonded logistics center, the initial measure was to apply for projects that extend the industrial chain. High technology always follows the length of the industrial chain. Therefore, the entire manufacturing process of some high-value and high-performance products can be divided into (continued from page 61) markets, improving the current state of the domestic retail industry and enhancing the competitiveness of my country's retail industry internationally.
