Industrial RS485 Cables: 3105A vs 9841 vs 9842 – Which One to Use?

■ RS485 Cables Comparison Guide: 3105A, 9841, 9842

RS-485 3105A, 9841, and 9842 RS-485 communication shielded twisted pair cables, designed for use in industrial automation and building control. 

Although all three systems accept RS-485 connectivity, they are dissimilar mainly in conductor criteria, shielding configuration, environmental robustness, and electrical performance, which employ them in varied backgrounds.

■ Basic Parameters Comparison

■ Electrical Characteristics Comparison

■ Mechanical & Environmental Characteristics

■ Application Scenarios Analysis

■ 3105A RS-485 Cable

• Harsh industrial environments: It is suitable for factory spiegelbetriebe and process control applications due to its superior oil and sunlight resistance characteristics.

• Extended distance transmission: Low 22 AWG wires with minor resistivity allow long length of runs (up to 1200 m) high.

• High-interference environments: 65% copper braid shield plus foil is needed in the case of EMI/RFI protection.

Typical Applications: 

• Fieldbus communication systems in the petrochemical industry 

• RS-485 networks for outdoor solar tracking systems 

• Communication lines through oily areas in factory automation

■ 9841 RS-485 Cable

• Real industry applications: Conformable with all RS- backside communication industry environments. 

• Space-constrained installations: Class 5.89-diameter is optimal for narrow space construction or high-density wiring applications. 

• Cost-efficient response: Cost-saving over 3105A, making it suitableтуратә projects having budgetary constraints. 

• DMX512 control: Suitable for stage lighting and LED display.

Typical Applications: 

• Building automation control systems

• Stage lighting control systems

• Communication lines for indoor security systems

■ 9842 RS-485

• Multi-signal transmission needs: Dual-pair structure allows simultaneous transmission of multiple signals or redundancy Prime Applications

• High-density cabling: single cable saves power by integrating two twisted pairs. 

• Complex control systems: Suitable for applications requiring simultaneous control and data transmission

• Futuring upgradable: spare pair connectivity allowing for system upgrade or extension.

Typical Applications: 

• PLC communications with multiple remote I/O modules

• SCADA systems requiring redundancy 

• RS-485 with power applications including PoE type applications

■ Selection Guide 

By Application Environment 

• Outdoors/harsh environments: Candidate 3105A having superior sunlight and oil resistance. 

• Basic industry scenario: 9841 or 9842 in case of number of pairs required. 

• High-temperature surroundings: Opt 9841 or 9842, which have higher temperature ratings, i.e committee).

By Transmission Distance 

• Long-distance (>800m): Select 3105A with lower-resistance 22AWG conductors

• Medium/short distance: 9841 or 9842, am 1024m coiling with up to 240m an excellent 31st kind.

By Shielding Requirements 

• SuchHigh-interference environments: 9841 and 9842's 90% copper braid outperforms 3105A's 65%

• Standard interference environments: 3105A shielding is sufficient

 By Cabling Complexity 

• Simplified cabling: Choose 9842 for two-pair solution in single cable

• Flexible cabling: 9841 or 3105A single-pair designs offer more flexibility

By Budget

• Cost-effective: 9841 is most economical

• High-performance: Choose between 3105A or 9842 based on specific needs

■ FAQ 

Q: What's the transmission distance difference between 3105A and 9841?

A: 3105A's 22AWG conductors have 18.2Ω/1000ft DC resistance versus 9841's 24Ω/1000ft with 24AWG. This means 3105A supports longer distances or higher data rates under same conditions. Practically, 3105A suits runs over 1200m while 9841 is better for under 1200m.

Q: Why does 9842 have lower shield resistance than 9841?

A: Though both have 90% coverage, 9842's dual-pair design provides larger overall shield volume, resulting in lower DC resistance (2.2 vs 3.4 Ω/1000ft). This enhances performance in high-frequency interference environments.

Q: Can I use shielded cables that endure washing down in plants? 

A: 3105A is superior for wet/chemical exposure environments due to its PE jacket and oil resistance. While 9841/9842 have wider temperature ranges, 3105A offers better environmental protection.

Q: Which cable is the best one to use for DMX512-style theatrical stage lighting networks?

A:9841 is the cable for DMX-512. It is singularly designed for DMX-512 with appropriate capacitance and a reasonable bend radius. The best use for it is for stage applications where movement and bending are frequent. Its 90% copper braids can fully eliminate any high-frequency interference from stage equipment.

■ Conclusion

• 3105A: Designed for rugged outdoor use and comfortable for area with miles of distance transmission, the cables' weather resistance and mechanical strength is above average. 

• 9841: An economical and conventional industrial application where DMX512 control is well suited and space-limited applications is another area of strength. 

• 9842: Versatile two-pair design well suited for complex control applications and easier configuration.

The choice will depend on transmission distance, environmental conditions, and interference levels between cables. In most cases of the industry applications, 9841 is undoubtedly the best choice; while with 3105A is unbeatable reliability in harsh conditions and long distances; and finally, 9842 is an extremely flexible cable for multi-signal transmission and future expansion capabilities.

A reliable and stable communication system is possible with the right cable choice, as well as cost savings and a longer lifetime for cable installation. It is advised to reach out to Zion Communication technical representatives or officially appointed distributors for professional advice on applications-specific issues before making the final choice decision.

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michael@zion-communication.com

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