Introduction to various types of cables: optical cables

2026-04-08

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shielded control cable KVVP multi core cable.jpg

Control signal cable is a specialized cable used for transmitting low-voltage control signals, monitoring signals, and data instructions, widely used in industrial automation, power systems, mechanical equipment, and other fields. Its core function is to ensure the accuracy, anti-interference and reliability of the control system. Here is a detailed analysis:

1. Definition and core characteristics of control signal cables

Basic Definition

Used for connecting PLC, sensors, frequency converters, instruments and other equipment, transmitting analog signals (such as 4-20mA) or digital signals (such as RS485, CAN bus).
Typical voltage level: 300/500V (low voltage control circuit).

Key characteristics

Anti interference capability: Suppress electromagnetic interference (EMI) through a shielding layer (copper mesh/aluminum foil) to ensure signal purity.
Flexibility: Multi strand thin copper wire conductor (Class 5 standard), suitable for frequent movement or bending scenarios.
Environmental adaptability: resistant to oil, acid and alkali (such as PVC/PUR sheath), flame retardant (compliant with IEC 60332).

2. Usage requirements and structural characteristics

Usage characteristics

Structural features

1. Due to the use of control signal cables for controlling measurement systems, it is required that the cables work safely and reliably;

2. Generally fixed laying, but at the connection between the cable and the equipment require softness and the ability to withstand multiple bends without breaking;

3. The working voltage is 380V and below, and the voltage of the signal cable is even lower;

4. The working current of signal cables is generally below 4A. When the control cable is used as the main equipment circuit, the current is slightly higher, so the section can be selected according to the line voltage drop and mechanical properties.

1. The wire adopts copper core, and the fixed laying adopts a single structure with an additional 7 twisted structures; Mobile adopts a 5-class soft conductor structure to meet the requirements of softness and bending resistance;

2. The insulation mainly uses materials such as polyethylene, polyvinyl chloride, natural styrene butadiene rubber, etc;

3. The insulated wire core should be twisted in the opposite direction to make the structure more stable; For outdoor cable laying, nylon rope filling is used to increase tensile strength, while co directional cable laying can increase flexibility;

4. Sheath: mainly made of polyvinyl chloride, chloroprene rubber, nitrile polyvinyl chloride composite, etc.

3. Control signal cable vs power cable

Comparison item	Control signal cable	Power cable
Voltage level	300/500V and below	0.6/1kV and above
Conductor cross-section	0.5-6mm² (fine cross-section multi-core)	1.5-500mm² (coarse cross-section multi-core)
Shielding requirements	Usually requires a shielding layer	Only special models (such as variable frequency cables) are shielded
Typical standards	GB/T 9330, IEC 60502-1	GB/T 12706, IEC 60228

4. Core application scenarios

Industrial automation
- Connect PLC and servo drive (such as KVVP for CNC machine tools).
- Transmit analog signals (such as shielded twisted pair cables for PT100 temperature sensors).

Building control
- Fire alarm system (WDZ-KYJY halogen-free flame retardant type).
- Signal transmission from elevator control cabinet to car (anti bending type).

Energy and electricity
- Substation relay protection circuit (such as KVVP2-22 armored shielded cable).
- Wind power pitch control system (low temperature resistant -40 ℃ cable).

5. Selection and Construction Points

Key parameters for selection

Shielding effectiveness: Copper mesh shielding ≥ 60dB (at 1GHz), aluminum foil shielding ≥ 40dB.
Bending radius: ≥ 6 x cable diameter (fixed installation), ≥ 10 x diameter (mobile use).
Temperature range: PVC sheath (-15 ℃~70 ℃), silicone rubber sheath (-60 ℃~180 ℃).

Construction specifications

The shielding layer needs to be terminated 360 ° (such as with metal clamps) to avoid "pig tail" grounding.
Avoid parallel laying with power cables (minimum spacing ≥ 30cm), and form a 90 ° angle when crossing.

6. Industry Trends and Innovation

Digital upgrade: PROFINET cable: Supports Gigabit Industrial Ethernet (such as AWG22/4 twisted pair+double-layer shielding). Fiber optic composite control cable: Integrated fiber optic (such as GYXTZW) for long-distance anti-interference transmission.
Environmentally friendly materials: Halogen free sheath (LSZH), with a smoke transmittance of ≥ 60% during combustion (IEC 61034).
Intelligent diagnosis: Cable with built-in fiber optic sensing for real-time monitoring of wire breakage or insulation aging (such as ABB Ability™ Plan).

7. Summary: Control signal cables are the "capillaries" of industrial neural networks, and selection should focus on shielding level, flexibility, and environmental adaptability. With the advancement of Industry 4.0, high shielding and high bandwidth composite cables (such as cables+optical fibers) will become a trend.

※If you need to purchase Cable Materials, you can choose Wuxi Henglong Cable Material Co., Ltd., a well-known manufacturer in the Chinese cable materials industry.