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This article mainly introduces "how to realize the intelligent elevator management system based on the smart cloud Internet of things platform". In the daily operation, it is believed that many people have doubts about how to implement the intelligent elevator management system based on the smart cloud Internet of things platform. The editor consulted all kinds of materials and sorted out simple and useful operation methods. I hope it will be helpful for you to answer the doubt of "how to realize the intelligent elevator management system based on the smart cloud Internet of things platform". Next, please follow the editor to study!

1 composition of elevator control system

The design of the intelligent elevator control system based on STC89C52RC single chip microcomputer should meet the following requirements, such as the operation logic of the basic elevator, the input and output of floor information, voice broadcasting, remote control, operation log upload and alarm functions, as shown in figure 1.

2 system hardware design

Before the start of the hardware design, the devices used will be simulated in the program, divided into modules, and upgraded in the basic design after the completion of the basic elevator function [5].

2.1 Overview of main modules of the system

1) the minimum system module of single chip microcomputer

In this paper, STC89C52RC single chip microcomputer is selected for MCU, and the minimum system is composed of 11.059 2MHz crystal oscillator clock circuit and reset circuit [6]. The program of each module is initialized, and it can also be used to get rid of interlock and prevent the program from running. It has built-in central processing core CPU, clock circuit and interrupt system, three 16-bit timers / counters and so on. It has the characteristics of low cost, low power consumption and high reliability. It can meet the requirements of this design.

2) 8155I/O port expansion module

The 8155 expansion module adds an additional interface to the system. 8155, which is the same as the single chip microcomputer, has a 40-pin dual in-line package with a total of 4 sets of I am O ports. AD port and single-chip microcomputer PO port are used as data and address bus to solve the problem of lack of Icord O port in the process of using single-chip microcomputer. The use of external hardware to expand the system, strengthen the single-chip microcomputer I hand O port, to meet the needs of complex operation.

3) L298N motor drive module

By burning the smart cloud firmware GAgent, the esp8266 module links the Internet to communicate with the cloud, enables the device to access the smart cloud Internet of things platform, uploads the elevator running status, and can issue device-side control instructions through the mobile phone APP. The control flow is shown in figure 2. Combined with the smart cloud Internet of things platform to design a time-saving elevator floor reservation mode, as well as the elevator maintenance mode in special circumstances, and record the elevator instructions to facilitate later maintenance. ESP8266 needs 3.3V power supply, so it is necessary to design the corresponding power supply circuit for ESP8266 when designing the circuit.

Smart cloud control flow chart

In the single-chip microcomputer STC89C52RC, the protocol is used to access the smart cloud Internet of things platform, the bit rate is 9 600b/s, using a question-and-answer, data packet reporting, sending communication interaction form [9-10]. Create 8 Boolean data nodes in the platform, using smart cloud APP, through simple switch selection, you can modify the content of the packet and control the device side, and issue instructions. The packet format is shown in Table 1.

Table 1 Communication packet format

5) ISD1820 voice module

As a humanized element, the ISD1820 voice module synthesizes voice by recording iFLYTEK to inform passengers that the elevator has arrived on the pre-selected floor. The ISD1820 voice module is connected to the single-chip microcomputer pin, and the rising edge trigger mode is selected. The high level of the single-chip microcomputer pin triggers the voice module to play, and the whole voice can be released.

Buzzer alarm module

In case of emergency, the program should respond first, so the alarm control is written in the external interrupt 0, and the external interrupt 0 has the highest priority in the interrupt system. The alarm module uses a buzzer and is triggered by a button through a transistor amplifying circuit. The corresponding algorithm is designed in the program, so that when passengers encounter an emergency, the distress signal can be transmitted to the security personnel in time. Make sure that you can also respond quickly to [11] while the program is running. In the way of hardware anti-jitter, the 0.2 μ F ceramic chip capacitor is connected in parallel at both ends of the button to counteract the mechanical jitter through the delay of charging and discharge of the capacitor to ensure that the alarm button works normally.

7) LED and digital tube display module

The display module completes the function of 7-bit LED light to display the number of floors triggered and the delay of opening and closing doors. Any floor in the elevator external button triggers the request, and the corresponding LED light is on, indicating that the floor call request is successful. Simulate the elevator opening and closing state with a red LED light. The 4-bit common anode digital tube shows the current floor and up and down status, the segment selection signal line is connected with the PB port of 8155, and the bit is connected with the PA0-PA3 port. The first is "U" for elevator uplink or "d" for elevator downlink, the fourth bit shows "1-4" for the current elevator location, the digital tube displays "StOP" in maintenance mode, and the elevator does not respond to any floor call requests.

8) the matrix keyboard simulates the keys inside the elevator and the floor, confirming the trigger floor by scanning row by row, and the cloud instructions of the matrix control module and the WiFi module as input signals [12] to complete the call request of the floor of the equipment.

2.2 system Protues simulation

Before carrying on the physical design, carry on the Protues simulation, simulate the running state of the equipment side in the simulation, use Keil C51 to write the program, generate the HEX file, run in the simulation, verify the correctness of the design and running logic of the program, the wiring in the simulation can provide some reference for the physical welding, the system Protues simulation is shown in figure 3.

2.3 hardware implementation

In the process of building the hardware, simulate the real running state of the elevator as far as possible; reasonably use the delay function to prevent excessive CPU occupation; the physical welding should avoid virtual welding, affecting the safety and stability of equipment operation, and complete the hardware as shown in figure 4.

Physical drawing

3 system software design

The system is designed at the equipment end level to complete the basic functions of the elevator, improve the elevator car scheduling operation algorithm, distinguish the elevator status of the upper and lower floors, and ensure that the elevator can respond to the uplink request of the high floor when the elevator is uplink, and respond to the downlink request of the lower floor when the downlink request is completed. When the upstream (downlink) request is completed, it will respond to the floor request of the opposite direction. The operation scheduling logic is shown in figure 5.

The internal and external keys of the elevator are designed to simulate the call request of the elevator, the L298N drive motor turns forward and reverse to simulate the uplink and downlink of the elevator car, the voice module prompts passengers to arrive after the elevator reaches the pre-selected floor, and the alarm module uses an external interruption to ensure the priority response to the alarm request in case of emergency, the digital tube module displays the up and down link of the elevator and the position of the current floor, and the LED light lights up when the external key request is generated. Indicates that the user's call request has been successful.

On the cloud level, after accessing the Internet of things platform, the maneuverability of the elevator is enhanced, and the reservation mode of the elevator is expanded. The elevator can be dispatched by issuing instructions on the mobile phone, and the maintenance mode is suitable for dealing with the special circumstances of the elevator. after the mode is turned on, the call request of the device side will not be answered. Supervision of elevator equipment in the cloud, combined with the progress of modern electronic technology, to improve the efficiency and stability of elevator use under the premise of ensuring safety [13].

In this program design, C language programming is used to complete the functional goal of the design. The software design includes the cooperation of the main program and each subprogram, calling the corresponding Ihand O port to judge the input signal logic and make a response. After the system is powered on, initialization is carried out first, and the main program continuously executes the keyboard scanning program. when there is keyboard input, the main program calls the timer interrupt program, and reads the keyboard input information through row and column scanning mode. call the display subroutine and motor drive subroutine to transmit the up and down information of the elevator floor and the location information of the current floor to the operator, as shown in figure 6 and figure 7.

4 system testing

1) after the device is powered on, the device is automatically connected to the configuration network after the device is powered on, and the floor command is issued in the APP of the phone, and the device responds. In the maintenance mode, it does not respond to the floor input request of the device, and the alarm button works normally. The test effect is shown in figures 8 and 9.

Elevator dispatching logic diagram

Main program flow chart

Timer flow chart

2) in the running logic test of the equipment side, the elevator can respond to the request of the lower (higher) floor corresponding to the same direction at work [14], and respond to the reverse floor request after completing the current call request; alarm test, the alarm request can be responded to at any time when the program is running, and the test results are shown in Table 2.

3) the test results show that the control of the mobile phone side has a higher requirement for the network, and the bad state of the network may result in the loss of transmission data, which will not affect the device side. In most cases, floor calls and alarm calls can be correctly and timely responded to, achieving the expectations of this design. In view of the network signal problem, according to the different use scenarios and uses, GSM module or WiFi module can be used as the information transmission device [15] according to local conditions to ensure the realization of the equipment function.

Cloud control test

Maintenance mode test chart

Test result data sheet

At this point, the study on "how to implement an intelligent elevator management system based on smart cloud Internet of things platform" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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