1 Introduction
The application and development of the Internet of Things (IoT) in elevators in China has gone through several stages, from initial elevator status monitoring and basic information querying, to emergency rescue for people trapped in elevator malfunctions, and then to on-demand maintenance and smart elevators. The application scenarios are becoming increasingly in-depth, and its contribution to the elevator industry is constantly growing. Elevator manufacturers, elevator maintenance companies, elevator component manufacturers, elevator users, and government regulatory departments have all benefited from the IoT. With the deepening development of the IoT, unified management and standardization are becoming increasingly important. Various companies are establishing enterprise-level IoT platforms to manage the elevators under their jurisdiction. Local governments are also gradually building regulatory platforms to manage elevators within their jurisdictions. Some regions have already issued technical specifications for the IoT and interface standards for regulatory platforms, laying a solid foundation for the healthy and standardized development of the IoT. However, the regulatory interface standards set by different local governments are not entirely the same, with differences in interface types, encoding formats, security guarantees, and data formats. Further standardization and optimization of the interface are needed from a practical application perspective to provide a reference for other regions to establish regulatory platforms in the future.
2. Research on Data Interface of Regulatory Platform
2.1 Comparison of data interface parameters of IoT monitoring platforms in various regions
The following are the locations that have already established regulatory platforms and formulated connection standards, along with the names of those standards:
(1) Fujian, Longyan, "Standard Agreement for Third-Party Access to Elevator Rescue Public Platform"
(2) Guangdong, Shenzhen, SZDBZ-116-2014 Technical Specification for Elevator Operation Monitoring System
(3) Jiangsu, Wuxi, "Elevator Platform and Service Interface Protocol"
(HTTP Method) V4.0
(4) Liaoning, Shenyang, "Requirements for Liaison with Heping District Government"
(5) Xi'an, Shaanxi Province, "DB6101T 3006—2019 Technical Specification for Elevator Internet of Things Operation Monitoring System"
(6) Shanghai, "Data Interaction Specification for Remote Monitoring System of Integrated Smart Elevator Professional Management Service Platform_v1.1"
(7) Huzhou, Zhejiang Province, "Special Equipment Application Platform API Documentation - Elevator V1.5"
(8) Jinhua, Zhejiang Province, "Technical Specification for Elevator Safety Operation Monitoring System V2.0"
(9) Zhejiang, Ningbo, "Elevator IoT Government Platform Data Interface"
(10) Zhejiang, Wenzhou, Technical Specifications for Intelligent Monitoring Device System for Elevators
Table 1 compares the standards established in various regions from the perspectives of transmission protocols, encoding formats, parameter formats, and audio/video streaming protocols.
Table 1 Comparison of Interface Parameters of Elevator IoT Monitoring Platforms in Various Regions
2.2 Data Content of IoT Monitoring Platforms in Various Regions
(1) Basic elevator information
This includes: elevator registration code, elevator manufacturer, elevator category, model, manufacturing date, manufacturing serial number, installation address (some places also record the latitude and longitude information of the elevator location), internal name (number), installation unit, installation date, emergency rescue phone number, maintenance unit name, maintenance unit organization code, maintenance unit head, maintenance unit emergency rescue phone number, last maintenance date, property owner, user unit name, user unit head, user unit phone number, user unit organization code, administrative region code, elevator usage status, usage occasion, usage location, registration date, commissioning date, inspection agency name, inspection unit, last inspection date, last inspection result, next inspection date, physical floors (vertical elevator), number of stops (vertical elevator), rated speed, rated load (vertical elevator), theoretical transport capacity, lifting height (escalator), tilt angle (escalator), nominal width (escalator), and data update time.
(2) Real-time elevator operation data
Includes: Elevator registration code (existing elevators), Manufacturer's Unified Social Credit Code (newly installed elevators), Factory serial number (newly installed elevators), Current service mode - Escalator/Vertical elevator (Out of service, Normal operation, Maintenance, Firefighting return, Firefighter operation, Emergency power operation, Earthquake mode, Unknown), Current service mode - Escalator (Out of operation, Normal operation, Maintenance, Unknown), Operating status - Escalator/Vertical elevator (Out of service, Operating), Operating direction - Escalator/Vertical elevator (No direction, Up, Down), Operating direction - Escalator (Energy-saving out of service, Nominal speed up, Energy-saving decelerated up, Nominal speed down, Energy-saving speed down), Unlocking area - Vertical elevator ( Elevator car in unlocked area, elevator car in non-unlocked area), current floor - vertical elevator, whether there is anyone in the car - vertical elevator (occupied, unoccupied), whether the door is closed (door closed, no door closed signal), machine room temperature - vertical elevator, machine room door open/closed - vertical elevator, car door status - vertical elevator (unknown, closing, door closed, opening, door open, door locked, unsafe closed state), hall door status - vertical elevator (door locked, no door locked signal), car overload - vertical elevator (overloaded, not overloaded; unknown, normal, full load, overloaded), traction machine status - vertical elevator ( Standby, traction mechanism brake lifting, traction mechanism brake releasing), real-time number of passengers via facial recognition - elevator, passenger behavior mode - elevator (normal, uncivilized behavior, dangerous behavior), current load of the car, cumulative number of runs, cumulative running time, pit humidity, voltage of IoT monitoring device, power supply information of IoT monitoring device (self-contained power supply, external power supply), battery information, network registration number of monitoring device, comprehensive fault signal, detailed fault code, internal call signal, real-time video access link, real-time voice access link, door opening button signal, running speed, whether there is a power outage (unknown, power outage, power on), self-learning running status (unknown, normal, return to base station, return to the nearest leveling floor), sampling time.
(3) Elevator statistics
This includes: elevator registration code (existing elevators), manufacturer's unified social credit code (newly installed elevators), factory serial number (newly installed elevators), total number of elevators connected to the platform, number of elevators online, number of times the equipment door is opened, cumulative number of times the equipment door is opened and closed, energy consumption statistics, cumulative equipment operating time, cumulative number of times the equipment operates, number of times the equipment wire rope (belt) is bent, cumulative operating distance of the equipment, number of passengers, and sampling time.
(4) Fault alarm data
This includes: timestamp (accurate to the second), elevator registration code, elevator equipment number, monitoring device number, data generation time (current device time), event source, occurrence time, fault code, preliminary fault cause assessment, alarm content, whether people are trapped (trapped, not trapped), entrapment start time, alarm type (unknown, automatic, manual), rescue contact person, rescue contact person's phone number, rescue unit, alarm call connection time, number of trapped passengers, rescue unit, whether there are any casualties, number of injured, number of fatalities, whether 120 was notified, time of 120 notification, whether rescue was successful, and current rescue status (initial report, rescue initiated). The system includes: arrival at the scene, rescue completion, location coordinates of rescue personnel, arrival time of rescue personnel, rescue completion time, alarm receiving time of maintenance unit, dispatched maintenance personnel, maintenance completion time, status indicator of whether fault handling is completed, elevator speed, door open/close status (open, closed), elevator operation mode (elevator electric lock, elevator maintenance, elevator fire protection, elevator operator, elevator automatic, elevator dedicated, elevator shaft self-learning, full load, overload, other), faulty floor, power supply status (normal, abnormal), running direction (downward, upward, stopped), current fault status, fault recovery time, video stream address, and status (added, cleared).
(5) Elevator maintenance information data
It includes: elevator equipment code, elevator equipment number, inspection device number, maintenance order ID, maintenance status (not started, started, completed, closed), maintenance cycle (half-month, quarterly, semi-annually, annually), maintenance unit credit code, maintenance unit, responsible maintenance personnel, responsible maintenance personnel's phone number, maintenance date, whether repairs occurred, repair content, start time, end time, and remarks.
(6) Elevator event data
This includes: manufacturer number, peripheral number, elevator registration code, event code, event occurrence time, event start time, event end time, process record list (process record number, occurrence time, process record content), voice file list (voice file number, voice intercom occurrence time, access voice file link address), video file list (video file number, video file occurrence time, video recording location (car, machine room, car top), access video file link address), event content description, elevator resumes automatic operation mode (not resumed, resumed), main power failure (not failed, failed), service stopped (not stopped, service stopped), maintenance mode (not entered, entered), fire return mode (not entered, entered), firefighter operation (not entered, entered), emergency power operation (not entered, entered), earthquake operation mode (not entered, entered), and other event codes.
(7) Monitoring terminal equipment data
It includes: elevator equipment code, elevator equipment number, monitoring device number, equipment online status (unknown, offline, online), status type (monitoring device, camera, unknown, other), online/offline time, other, online rate, data acquisition device sending timestamp, and platform sending timestamp.
(8) Audio and video data
It includes: elevator registration code, video stream URL, interface expiration time, alarm number, voice intercom server address, device serial number, signaling server address, signaling server port, network penetration server address, network penetration server port, WSS port, called account, calling account, and calling account password.
2.3 Comparison of data interface security and feasibility of IoT monitoring platforms in various regions
The security solutions for APIs in various regions are basically based on tokens. The access party applies for Appkey and AppSecret from the platform provider offline. The access party needs to keep the Appkey and AppSecret safe. If they are leaked, they need to apply for them again.
Before calling the platform's API, the access party needs to obtain a token using the given Appkey and AppSecret, and then use the token to access the corresponding API. Tokens usually have an expiration date, but there is generally no best solution; each case needs to be analyzed individually.
Tokens can enhance API security, restrict unauthorized access to data, and thus provide a certain level of data security. Tokens are a mature solution, widely accepted by developers due to their ease of use, and are used in systems where security is not paramount. While tokens offer many advantages, they also have significant drawbacks. They increase the difficulty of integration, and the need for an Appkey and AppSecret when obtaining a token increases the risk of data theft. Therefore, some API security solutions have abandoned tokens in favor of signatures. Signatures avoid transmitting the AppSecret over the network and eliminate the need to handle token expiration issues.
2.4 Research Conclusions
(1) Through comparison of the interface connection methods of various platforms, it is found that they all basically adopt the RESTful style interface. However, the RESTful style API is not suitable for real-time data transmission, and it is recommended to use the WebSocket method.
(2) The biggest difference between regions lies in the content of various data, such as elevator records and real-time data. The fields vary greatly from region to region. It is recommended to reverse the signal requirements from the perspective of on-demand maintenance.
(3) Data security. In addition to recommending an upgrade to the authentication method, the HTTPS protocol should be considered.
Conclusion
On-demand maintenance and smart elevators rely on the Internet of Things (IoT) for elevators. Based on a study of existing elevator monitoring platforms in multiple locations, this paper comprehensively compares various technical indicators, including interface type, interface security, data encoding format, parameter format, and audio/video stream protocols, and provides optimization suggestions for the monitoring platform interface, offering a reference for other elevator industry regions that have not yet established monitoring platforms.
