RS485 Cable Product Introduction & Selection Guide

■ What is an RS485 Cable?

RS485 cable is a particular type of communication cable, which is utilized for differential signal transmission in control systems for industries, automation tools, and building management networks. It provides a two-wire or multi-pair system with a balanced signal for long-distance, high-speed, and noise-resisting data communication. The canonical impedance ranges around 120 ohms.

RS485 cables are widely used in:

• Industrial Automation Systems

• Building Automation & Smart Buildings

• Intelligent Transportation Systems (ITS)

• Security and Surveillance Systems

• Smart City & IoT Applications

• Power & Energy Management

■ Common Applications of RS485 Cable (Detailed Guide)

RS485 cables find a great deal of application in industrial automation, intelligent building control, transport mechanisms, and energy efficiency due to their extended transmission range, better resistance to electromagnetic interference, and the ability to communicate with multiple nodes.

I Industrial Automation Systems

Applications: 

Facilitate communication among PLCs, DCS systems, inverters, sensors, and other equipment employed in industry. 

Exploited for information collection as well as for control signal transfers. 

Cable Requirements: 

• Long-distance transmission (up to 1200 meters). 

• Superlative EMI shielding. 

• Usually use double-shielded RS485 cables (foil + braid). 

Example: 

In an automotive assembly line, RS485 cables serve the function of connecting several PLCs, which ensure the procedure's synchronization by keeping the robotic arms and conveyor belts in motion and detecting the parts.

II Building Automation & Smart Buildings

Applications: 

• HVAC control (heating, ventilation, air conditioning). 

• Intelligent light fixtures (automatic on/off, dimming). 

• Elevator operation. 

• Entry control, time attendance, alarm connections. 

Cable Requirements: 

• True signal transmission. 

• Support for multi-dropped bus topology. 

• Often utilize foil-shielded or unshielded RS485 cables in an indoor environment. 

Example: 

In a smart office building, a more efficient energy-saving operation is achieved using an RS485 bus to connect floor lighting, which is centrally controlled.

III Intelligent Transportation Systems (ITS)

Applications: 

• Traffic lights automation. 

• Wireless management of LED signs. 

• Road surveillance, including linking of systems. 

• Toll station installations where communication devices are installed. 

Cable Requirements: 

• Outdoors must resist UV and have weather resistance. 

• High EMI resistance → deploy shielded and armored RS485 cables. 

• High stability and instant responsiveness. 

Example: 

Along highways and roads, remote toll barriers and clearance units are connected with the central server via RS485 to ensure the toll is remotely controlled, and toll clearance stat is feedback to the server.

IV Security and Surveillance Systems

Applications: 

• Smart meters (electricity, water, gas). 

• Central management system for public street lights. 

• Environment monitoring sensors (air quality, temperature, humidity). 

Cable Requirements: 

• Ranging from simple node network to large large node network. 

• Routing complexity (under the ground, over the ground). 

• High stability → recommend armored PE jacket RS485 cables. 

Example: 

In smart residential areas, RS485 cables direct data flow from electric meters to data concentrators for automatic remote meter reading.

V Smart City & IoT Applications

Applications: 

• The communication pertaining to the linkage between the UPS and the battery banks. 

• Observance and control of substation equipment. 

• Getting required data for the PV inverter communication. 

• Alarm connection for the electrical devices. 

Cable Requirements: 

• High insulation capable of withstanding strong signal interference. 

• Corresponds to both indoor and outdoor usage where LSZH jackets or PE jackets are used. 

• One of the essential elements for stable communication in high-voltage sectors. 

Example: 

RS485 cables have the same role in a solar power farm as in any other power generation source: They connect PV modules to inverters for real-time monitoring and regulatory purpose.

VI Power & Energy Management 

Applications: 

• The communication pertaining to the linkage between the UPS and the battery banks. 

• Observance and control of substation equipment. 

• Getting required data for the PV inverter communication. 

• Alarm connection for the electrical devices.

Cable Requirements: 

• High insulation capable of withstanding strong signal interference. 

• Corresponds to both indoor and outdoor usage where LSZH jackets or PE jackets are used. 

• One of the essential elements for stable communication in high-voltage sectors. 

Example: 

RS485 cables have the same role in a solar power farm as in any other power generation source: They connect PV modules to inverters for real-time monitoring and regulatory purpose.

■ Why Choosing the Right RS485 Cable Matters?

Not all RS-485 cables are created equal. In terms of electrical noise, mechanical strain, or extreme conditions, some cables are more suitable than others. Every element, such as shielding type, insulator material, and jacket, plays a crucial role in determining the reliability of communication, durability, and suitability for the installation environment (designated by indoor, outdoor, plenum, or riser).

To help users select the correct cable, we’ve analyzed the four core structure differences in RS485 cable design, sorted by priority based on real-world application impact:

■ Shielding Type Comparison (Most Critical)

The shielding protects the cable from electro-magnetic interference (EMI) and ensures that it does not distort the signal.

✅ For strong EMI environments or long-distance transmissions, Foil + Braid or Foil + Braid + SWB is recommended.

■ Jacket Material Options

The exterior coating provides protection to the internal structure of the cable and limits its installation location areas.

✅ Choose LSZH for public buildings, PE for direct burial or sunlight exposure, and FEP for high-temperature or oil environments.

■ Insulation Material Comparison

Insulation induces changes in signal attenuation, capacitance, and temperature resistance.

■ Conductor & Pair Count

The magnitude of the conductor and the number of pairs twisted determine the capacity and the layout of the system.

✅ More pairs = more nodes; thicker wire = better transmission.

■ RS485 Cable Selection Guide by Application

Need assistance? If you require our help, then contact our team for technical consultation or custom RS485 cable solutions.

michael@zion-communication.com

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