Elevators are crucial transportation tools in intelligent buildings. With the proliferation of high-rise intelligent buildings and the increasing number of elevators, their importance in modern architecture is becoming increasingly apparent. Ensuring the efficient, reliable, and safe operation of elevators has garnered growing attention. Common issues include: elevator malfunctions preventing timely arrival of maintenance personnel; lack of effective communication tools within elevators hindering maintenance staff from understanding the situation and providing necessary reassurance, causing significant psychological and physical stress for trapped individuals; and the inability of maintenance personnel to access daily operational records and monitoring data increases the difficulty of troubleshooting and significantly prolongs repair time. Remote elevator monitoring technology emerged to address these issues. The REM (Remote Elevator Monitor) system represents advanced technology in elevator control, essential for elevator management, maintenance, and ensuring safe operation. It is a necessary means to promptly detect, analyze, and resolve faults. Remote elevator monitoring represents another major technological advancement in the Chinese elevator industry, following PLC control systems and VVVF speed control systems. Overall Design of Real-Time Remote Monitoring System for Elevator Operation Status As a service accessory for elevators, the system needs to complete the task of remote elevator monitoring. Its basic structure consists of three parts: a server (host computer) at the monitoring center, a modem, and a front-end data acquisition system (front-end machine). The overall system structure is shown in Figure 1. It is a distributed system. The host of this distributed system is the server at the monitoring center, whose hardware is a PC. The slaves are the front-end machines in the field. The host and slaves are connected to the public telephone network via a modem. The entire system can be hundreds or thousands of kilometers apart. The front-end machine is a single-chip microcomputer system responsible for collecting and processing the elevator's operating status and related data. Through specific interface circuits, it can communicate with various types of elevator control systems (lower-level machines). The main working principle of the elevator remote monitoring system is that the elevator control system PLC (lower-level machine) converts its I/O control port status and other data into specific status flags (such as converting the switch status in the I/O area into data in the DM area), and transmits this flag to the front-end machine in the public telephone network. The front-end machine then transmits the data to the PC, thereby enabling the PC to monitor the PLC's operating status. Figure 2 shows the hardware schematic diagram of the front-end unit of the elevator remote monitoring system. This system only studies elevators controlled by Mitsubishi PLCs. The design of the front-end unit is the core of the elevator remote monitoring system's functionality. Its design requirements are to complete data acquisition, fault detection and judgment of the elevator control system, and communication with the server. The design process is mainly divided into six stages: selecting hardware according to design requirements, building the hardware circuits of each module, designing the programs of the corresponding modules, debugging the hardware and software within the modules, designing the front-end unit's software, and debugging the entire front-end unit system. [align=center] Figure 1 Overall structure diagram of the monitoring system Figure 2 Hardware schematic diagram of the front-end unit of the elevator remote monitoring system[/align] Monitoring System Upper Computer Monitoring Software Design The upper computer monitoring software design of the elevator remote monitoring system mainly includes dynamically displaying the elevator's operating status, operating the elevator fault information and user information database, and remotely communicating with the front-end unit. It also involves processing the data sent by the front-end unit and completing the analysis and judgment of elevator faults. The monitoring software can be implemented using VB or existing industrial control software such as InTouch or KingSCADA. However, considering cost and program design flexibility, VB is used. The MSComm control and its communication with the modem. The purpose of using the MSComm control is to allow users to design a system that can communicate and transmit data with a serial port. Therefore, information flows along the hardware lines. This control provides the following two methods for handling information flow: Data Reception. In this design, mscomm1.inputmode=1, and data is transmitted and received in binary form. `dim store() as byte` 'Assigns the variable `store` to a dynamic byte array. `dim rv as variant` 'Assigns the data in the input buffer to the variable `rv` after removing the frame header. `select case mscomm1.commevent case comevreceive rv=mscomm1.input store=rv end select` Data Processing. Because the first 31 bytes of data uploaded by the front-end machine (30 running status information and 1 fault information) each represent a Boolean variable indicating the elevator's running status; while the last 11 bytes represent the analog A/D sampling value, different methods should be used for processing. For the first 31 bytes received by the host computer, since byte-type variables are represented in decimal in VB, the binary numbers transmitted from the front-end machine are automatically converted to decimal numbers when received into byte-type variables. Therefore, we need to restore the decimal data to binary numbers. Taking the variable store(0) as an example, the specific method is: divide store(0) by 2 continuously and take the remainder 8 times (format: remainder = store(0) mod 2). If the remainder result is 1, it is true; if it is 0, it is false. The order of taking the remainder from first to last is the order of the transmitted binary bytes from low bit to high bit. For the A/D conversion value, since the front-end machine is set to 8 bits, the value obtained from the A/D conversion is divided by 255 and then multiplied by the actual range of the number. Data transmission This design only dials and sends the flag byte at regular intervals. Dial: num="87401740#" mscomm1.output ="atdt"& num&vbcrlf Timed send flag byte: Enables the front-end unit to send data to mscomm according to the time set by the host computer. Assume the front-end unit receives data as bbh and then transmits the data to the host computer. Design of Real-Time Dynamic Screen for Elevator Monitoring The screen design consists of two parts: signal input, including internal selection, external call, and function selection (normal, maintenance, automatic, driver, slow up, slow down, emergency stop, straight, fire, full load, overload); and dynamic display, including car position, counterweight position, hall door status, contact status, running status, running curve, and running parameters. When the elevator is in monitoring mode, the signal input part of the screen can receive data uploaded by the front-end unit via internal program variables. These data generally include: basic elevator information, total number of floors, car location, elevator direction of travel, elevator operating status, elevator speed, status of landing doors and their contacts, status of each contact, some operating parameters of the traction machine, status of the safety brake, car load, and temperature inside the car. In monitoring mode, the actions on the screen are entirely determined by the data transmitted from the front-end machine of the elevator. In demonstration mode, the signal input to the screen can be entered by clicking the mouse; at this time, the dynamic actions of the screen are determined by the program's design. Figure 3 shows the elevator operation control interface. [align=center] Figure 3 Elevator Operation Control Interface[/align] Conclusion This project utilizes communication network technology to develop a computer-based remote real-time operation monitoring system for elevator operation status, providing a timely, convenient, and intuitive solution for the discovery, analysis, and troubleshooting of elevator faults during operation.