The principle of industrial Ethernet cable control servo motor
1.Working mode of servo motor controlled by Ethernet cable
Industrial Ethernet control servo motors control the movement of servo motors by transmitting digital control signals. This control method has the advantages of high accuracy, fast response speed, and good anti-interference performance compared to analog control method. In ağ kablosu control, control signals are converted into digital signals to achieve precise control of servo motor motion. Control signal transmission typically utilizes standard serial communication protocols such as RS232 and RS485.
2. Principle of Control Signal Transmission
The transmission of control signals for industrial Ethernet cables to control servo motors requires the use of multiple components such as encoders, DACs (digital to analog converters), PID controllers, and drivers. Encoders can convert mechanical motion into electrical signals, DACs can convert digital signals into analog signals, PID controllers can achieve signal correction and smooth output, and drivers are responsible for transmitting processed signals to servo motors, thereby achieving motion control of servo motors.
3、 The role of the controller
The controller is the core of industrial network cable controlled servo motors, responsible for receiving control signals and processing, correcting, filtering, transforming, and outputting signals. In the design of control systems, controllers also need to have certain computing, storage, and communication capabilities. The selection of a controller should take into account factors such as the nature of the control signal, control requirements, cost, and reliability.
4. Selection of Controller
1.Real time motion control communication
Parameter configuration and diagnosis
System networking
Mainstream industrial Ethernet protocol (servo specific)
| Protocol | Transmission Rate | Synchronization Performance | Representative Manufacturers | Cable Requirements |
|---|---|---|---|---|
| EtherCAT | 100Mbps | Ultra-high (µs level) | Beckhoff, Omron, Inovance | Cat5e/cat6a ethernet shielded cables |
| Profinet IRT | 100Mbps | High | Siemens | Profinet Type A/B/C dedicated cables |
| MECHATROLINK-III | 100Mbps | High | Yaskawa, Panasonic | M3 standard shielded Ethernet cables |
| EtherNet/IP | 100Mbps | Medium-High | Rockwell | Cat5e/Cat6a shielded cable |
Key characteristics of industrial Ethernet cables (servo specific)
1.Strong anti-interference design
Double layer shielding (SF/UTP, S/FTP): aluminum foil (F)+tinned copper braided mesh (S), shielding coverage>85%, resisting strong
● electromagnetic interference (EMI) generated by frequency converters and motors.
● Twisted pair structure: The wire pairs are tightly twisted in pairs to counteract differential mode interference, with a characteristic impedance of 100 ± 15 Ω.
2.High flexibility Ethernet cable and durability (drag chain scenario)
● Conductor: Stranded multiple strands of ultra-fine oxygen free copper wire (such as 28 × 0.08mm), resistant to repeated bending.
● Outer sheath: Made of PUR (polyurethane) material or high-quality modified PVC, resistant to oil, wear, low temperature, and torsion.
● Bending radius: drag chain type ≥ 10 x wire diameter, with a lifespan of 5 to 10 million bends.
3.transmission performance
● Category: Cat5e (100Mbps), Cat6a (1G), supporting speeds of 100Mbps/1Gbps.
● Number of cores: 8 cores (4x2x0.14mm ²). The Profinet/EtherCAT protocol mandates 8-core shielded wires to ensure electrical performance and anti-interference capability.
4、 Key points for selecting Double shielded Ethernet cable for servo systems
● Select type based on operating conditions
Fixed installation (inside the electrical cabinet): Choose Profinet Type A (PVC sheath, 4-core/8-core).
Occasional movement: Choose Type B (flexible PVC).
Drag chain/robot: Choose Type C (high flexibility PUR cable, bend resistant).
● Shielding and grounding
Shielded network cable must be used, with both ends of the shielding layer grounded (grounding resistance<10m Ω).
● connector
Priority RJ45 (industrial grade, IP67) or M12 D-code/X-code connectors, anti vibration and anti loosening.
5.Common Problems and Solutions
● Communication interruption, servo jitter, packet loss
Reason: Using ordinary unshielded network cables, shielding not grounded, wiring parallel to power lines.
Solution: Replace the dual shielded industrial Ethernet cable, with a distance of ≥ 30cm between the power line and the cable, or isolate them with a metal partition.
● nternal breakage of drag chain
Reason: Using ordinary fixed network cables, the bending radius is insufficient.
Solution: Use high flexibility drag chain dedicated Ethernet cable (PUR sheath, multi strand conductor).
summary
In servo motor systems, industrial Ethernet cables have completely replaced the traditional pulse+direction analog control method and become a standard configuration for bus servos. Its core value lies in simplifying wiring, improving speed, enhancing anti-interference, and achieving high-precision synchronization of multiple axes. It is an indispensable basic component for modern intelligent manufacturing, industrial robots, and CNC equipment.
