GUANGZHOU JINGXIN TECHNOLOGY CO., LTD.

In the process of intelligent elevator control system, the code reading module is the core key of data interaction. The coordinated design of its interface protocol, physical size and decoding process directly affects the system performance. When our scanning module needs to be applied to different scenarios, we need to understand the necessary characteristics of the code reading module of the elevator control system in various scenarios so that we can better use the code reading module of the elevator control system.

I  The Interface introduction of elevator control code reading module

In the integration of elevator control systems, the choice of interface protocol directly affects data transmission efficiency and system stability. The interface technology of the mainstream elevator control code reading module presents three major technical routes: RS485, Wiegand 26/34 interface, and TCP/IP cloud collaboration.

1. Five core dimensions of industrial-grade stability of RS485 interface

Using the differential signal transmission principle, the bit error rate is maintained at ≤1% within an effective transmission distance of 1200 meters. The interface can achieve batch authorization of 200 IC cards per second, and its twisted pair wiring solution can resist 50V/m electromagnetic interference in the elevator shaft.

1.1.Anti-common mode interference and electromagnetic compatibility

The core of RS485's industrial-grade stability lies in its differential signal transmission mechanism. Compared with the traditional RS232 single-ended signal (single-wire to ground transmission), RS485 uses twisted pair complementary voltage transmission (A/B line ±1.5-6V voltage difference), and achieves a leap in anti-interference ability through the principle of common-mode noise cancellation.

1.2 The Ability to adapt to extreme environments

Supports wide operating temperature range of -55°C to 125°C, and low temperature drift resistance (±5ppm/°C) ensures impedance matching accuracy. IP67 protection and 6063-T5 aviation aluminum housing, deformation under vibration ≤0.05mm. Medical-grade fluororubber seals withstand spraying of 84 disinfectant and meet ISO cleanliness standards.

1.3 Enhanced transmission reliability

The CRC-16+ARQ automatic retransmission mechanism makes the bit error rate ≤10⁻⁹, and the retransmission rate is reduced to 0.17%. The dynamic impedance matching technology supports short-distance (120Ω terminal resistance) and long-distance (RC network) modes, and the distortion rate is less than 2%. The baud rate adaptive module (such as Duoao DAIC-DT-RS485) realizes automatic switching between 9600-115200bps through SNR analysis, reduces the speed to ensure smooth communication when sudden interference occurs, and the recovery time is less than 200ms.

1.4. Topology Robustness

Supports 32-node cascading, MAX13487E chip realizes ±42V fault isolation, and the delay is only 15ms when a single node fails. The end reflection attenuation of hand-in-hand topology (such as Shanghai Center solution) is greater than 40dB, which is better than the star topology (bit error rate × 5 when the branch line is greater than 10m). The bus self-healing technology triggers 250mA current limiting protection and automatically restores communication within 10ms.

1.5. Real-time monitoring and maintenance

The MODBUS protocol extends the 0x17 function code to monitor 12 parameters in real time, including bus voltage (±5%) and temperature (±0.5°C). The LSTM neural network predicts the TVS tube attenuation model (Q(t)=Q₀·e⁻⁰·⁰⁰⁰²ᵗ), and the maintenance cycle is extended from 2 years to 5 years. The FOTA differential upgrade technology enables 500KB firmware to be transmitted in 30 seconds, with a success rate of >99.9%.

2. Wiegand protocol optimization solution (0.2 s ultra-fast response)

As a physical layer transmission standard, the Wiegand 26/34 interface achieves signal isolation transmission through independent data lines and clock lines. The module adopts a dual relay design and supports the hybrid verification process of "swipe card + dynamic password". The contact life of this module is still more than 2 million times under frequent operation of 15,000 times/day, which is particularly suitable for high-intensity use scenarios such as hospitals and government service centers.

In the intelligent elevator control system, the Wiegand 26/34 protocol is used as the core physical layer transmission standard, and the signal isolation transmission is realized through the DATA0/DATA1 two-wire differential architecture. The interface uses an independent clock line (CLK) to synchronize the data pulse, and each bit of data is characterized by a 100μs negative pulse, and the bit error rate is still maintained at 0.001% in the 50V/m magnetic field environment of the elevator shaft.

The module innovatively adopts a dual-relay redundant design. The main relay performs card swipe signal transmission, and the auxiliary relay is dedicated to dynamic password verification. The contacts are made of silver-nickel alloy. Under high-frequency operation of 15,000 times/day, the mechanical life exceeds 2 million cycles. The hybrid verification process integrates the offline TOTP algorithm. After swiping the card, the user needs to enter the dynamic password (6-digit time-sensitive number) within 5 seconds. The dual authentication reduces the risk of illegal intrusion by 98%.

The hardware level is equipped with a card reader module, which supports the recognition of national secret CPU cards with a sensing distance of 0-7cm, and the response time is compressed to 300ms). In response to high-intensity scene requirements, the module adopts a triple-strength design:

Structural protection: IP65 fully sealed glue filling process, able to withstand 84 disinfectant spraying for 8 hours continuously;

Electrical protection: TVS tube + PTC resistor combination, can resist ±15kV ESD impact;

Environmental adaptability: Industrial-grade wide temperature design (-25℃~85℃), vibration deformation ≤0.05mm.

When deployed in super high-rise buildings, it can handle an average of 120,000 elevator control requests per day, and the system MTBF (mean time between failures) reaches 100,000 hours. Through the protocol expansion interface, eight health indicators such as contact wear and signal distortion rate can be monitored in real time to achieve predictive maintenance.

3. TCP/IP cloud collaboration (authorization verification efficiency increased by 62%)

The reading terminal is connected to the Alibaba Cloud IoT platform through the HTTP/HTTPS protocol to realize real-time permission verification of dynamic QR codes. Its built-in AES-256 encryption chip can resist replay attacks, and the dynamic key is automatically updated every 30 seconds, reducing the visitor's waiting time from an average of 45 seconds to 17 seconds.

3.1 Network Architecture Design

PoE power supply solution: Deployment of IEEE 802.3af standard in elevator code scanning terminals

VLAN Division Strategy: QoS Guarantee for Elevator Control System and Security Video Stream Co-transmission

3.2 Protocol Stack Selection

MQTT vs HTTP: Comparison of message throughput in elevator status reporting scenarios (test data: MQTT protocol reduces bandwidth usage by 64%)

Secure transmission mechanism: Application of TLS 1.3 in elevator QR code information encryption (certificate chain management solution: Let's Encrypt automatic renewal mechanism)

3.3 Practical Cloud Connection

Alibaba Cloud IoT platform integration: module device shadow synchronization mechanism (latency: <200ms)

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II  Compact barcode module for elevator panels

1. In-depth analysis of dimensional engineering

The space optimization of the ultra-thin QR code reader needs to take into account both the module size and recognition performance. COB packaging technology can be used to integrate optical components and decoding chips into a micro PCB board with a thickness of up to 6.8mm, which is suitable for renovation projects such as elevator button panels. In terms of installation and adaptation, it is necessary to use positioning pins and elastic buckles to achieve precise fixation to ensure that the gap between the module and the panel is ≤0.2mm. This design is compatible with more than 90% of elevator control panels, while avoiding scanning blind spots caused by tolerances.

2. Ergonomic integrated technology innovation

2.1 Tilt installation solution:

The 30° tilt angle design allows the scanning optical axis to coincide with the normal line of the mobile phone screen, shortening the screen code recognition distance to 3-15cm. Actual measurement data shows that the first reading rate of this solution in a strong light environment is increased to 99.3%.

2.2 Anti-glare technology:

Nano-level matte coating technology can be used to control the surface roughness below Ra0.8μm, and combined with a 650nm red light fill system, the mirror reflectivity can be reduced from 85% to 12%. This technology is compatible with capacitive touch screen operations, and the false touch rate is less than 0.1%.

2.3 Technology Trends and Selection Recommendations

Renovation project: Give priority to ultra-thin modules with a thickness of less than 10mm, and use laser cutting to open holes to achieve seamless renovation.

New Projects: Recommend IP65+EMP dual protection module, suitable for metal panels and earthquake resistance requirements.

Ultra-high-rise scenarios: The module's wide temperature range performance and air pressure adaptability must be verified (a customized air pressure compensation algorithm is required for altitudes above 1000m).

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III  Barcode reading process of elevator control system

1. User authorization: permission generation and encryption

Users generate encrypted credentials through mobile APP, WeChat applet or property platform, which include floor permissions + time information (such as owner's long-term code and visitor's 5-minute dynamic code).

Dynamic encryption: The QR code uses the AES-256 encryption algorithm, embeds a timestamp (±1ms) and device fingerprint to prevent screenshot theft.

Visitor management: Owners can remotely issue temporary codes with path restrictions (such as only allowing access to the 15th floor and staying for 30 minutes). The QR code is sent in the form of an image, and visitors do not need to install the APP.

Multi-modal compatibility: Supports IC card, CPU card, and facial feature code to be written into the cloud permission library simultaneously, realizing "one-code access" cross-system linkage.

2. Intelligent code reading: multi-modal data collection

The elevator reader completes identity capture with three-in-one fusion technology:

13.56MHz radio frequency induction: 0.3 seconds to activate IC card, sensing distance 0-7cm (compatible with NFC mobile phone simulation card).

CMOS optical scanning: 1280×800 pixel sensor captures QR codes, supports 30° tilt recognition and strong light suppression (such as mobile phone screen reflection).

Liveness detection: The infrared fill light module determines the authenticity of the face/card and intercepts forgery attacks such as photos and videos.

3. Double verification: local + cloud collaborative authentication

Local offline verification:

The elevator control mainboard has a built-in STM32 chip, which can complete permission matching (such as floor restrictions and time period validity) in 0.3 seconds.

Supports storage of 100,000 blacklist entries, and can still intercept illegal credentials when the network is disconnected.

Cloud-based secondary authentication:

Transmitted to the cloud platform via 4G/5G to verify the authenticity of the user's identity + geographic location (to prevent theft in other places).

Blockchain technology records operation logs and generates tamper-proof data blocks with timestamps and device IDs

4. Command execution: contactless elevator control

Passive dry contact technology: simulates keystrokes through relays, lighting up the authorized floor in 0.2 seconds (such as closing the 16th floor key circuit).

Intelligent elevator dispatch logic:

Single-player mode: After scanning the QR code, the elevator goes directly to the target floor without stopping.

Multi-person mode: Elevators are automatically assigned according to the order of code scanning, increasing efficiency by 40% during peak hours

Abnormal handling: When a key short circuit/sticking is detected, the backup relay is automatically switched and the fault is reported.

5. Safety closed loop: dynamic failure and protection

Dynamic expiration mechanism: The QR code becomes invalid immediately after use, and the permission status is updated synchronously in the cloud.

Hardware protection: TVS tube + resettable fuse to resist 15kV electrostatic surge; silicone sealing ring to achieve IP65 dust and water resistance.

Attack Interception: 3 consecutive authentication failures trigger an audible and visual alarm and freeze the device for 30 minutes.

Data clearing: Clear the RAM cache after each operation to prevent memory leaks from causing permission violations.

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IV  Summary

The selection of elevator panel barcode modules needs to comprehensively consider space constraints, environmental harshness and human interaction requirements, and achieve standardized integration through modular design to promote the development of elevator Internet of Things towards lightweight and intelligent.

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Our products CR10, M2304, and Y31 support the above functions. We support retail, wholesale, and customization. If you have any needs, please contact us!

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