ELV Engineering
ELV engineering is an important branch of power applications, mainly involving information transmission and control systems for low voltage (≤ 220V/50Hz), and together with strong current engineering, it constitutes the two pillars of modern building electrical systems
Its core function is to achieve intelligent requirements such as communication, security, and automation control, including the following subsystems:
1、 Core System Composition
Communication system
Including telephone communication (three types of fax machines, video phones, etc.) and computer network systems, adopting a star topology structure, using Category 5 or above unshielded twisted pair cables to transmit digital signals, with a speed of up to 100Mb/s or more
Security system
Covering video surveillance (cameras, anti-theft detectors) and fire alarm systems (fire detectors, linkage control equipment), video signals are transmitted through coaxial cables, and control signals adopt a bus structure
Intelligent Building System
Including building automation (BA), office automation (OA), and fire automation (FA), subsystem integration is achieved through a comprehensive cabling system, such as air conditioning control, lighting regulation, etc.
2、 Technical features
Voltage level: safe voltage below 36V AC or 24V DC
Transmission medium: 75 Ω coaxial cable, twisted pair cable, optical fiber, etc
Development trend: Traditional subsystems have blurred boundaries, system integration has become mainstream, and structured cabling supports star topology
3、 Application scenarios
Widely covering commercial buildings, residential communities, transportation hubs and other places, for example, the background music broadcasting system uses multiple buses to transmit constant voltage audio signals, while parking lot management relies on the integration of weak current and computer technology to achieve intelligent control.