Overview
What are Servo / Feedback Cables?
Servo and feedback cables are specialized industrial cables designed to connect a servo drive (amplifier) to a servo motor. Unlike standard motor leads, servo cables are engineered to handle high-frequency switching noise (EMI) generated by Pulse Width Modulation (PWM). The power cable delivers the voltage and current required to move the motor, while the feedback cable (or encoder cable) transmits precise positional data back to the controller. High-quality shielding and low-capacitance insulation are essential to prevent signal degradation and ensure system stability.
Main Manufacturers
We stock and distribute genuine servo and feedback cabling solutions from the industry’s leading automation brands:
- Allen-Bradley: Specializing in Kinetix 5000 and 6000 series cabling.
- Siemens: Optimized for SINAMICS drives and SIMOTICS motors.
- Beckhoff: Leaders in One Cable Technology (OCT).
- Mitsubishi Electric: High-speed feedback for MELSERVO systems.
- Delta Electronics & Omron: Reliable solutions for general-purpose motion control.
- Schneider Electric, ABB, and Lenze: Supporting Lexium and multi-axis industrial robots.
Typical Applications
Servo cabling is critical in any environment requiring precision motion:
- CNC Machining: High-flex cables for multi-axis milling and turning centers.
- Robotics: Torsion-rated cables for 6-axis articulated arms.
- Packaging Machinery: Rapid start-stop cycles in pick-and-place lines.
- Automated Warehousing: Long-run cabling for shuttle systems and stacker cranes.
Selection Guide
To ensure compatibility and longevity, consider the following criteria:
- Motion Type: Determine if the cable will be stationary, occasionally flexed, or continuously moving in a cable track (C-track).
- Connector Type: Identify the motor-end and drive-end connections (e.g., M17, M23, M40, or D-Sub).
- Environmental Ratings: Check for oil resistance (UL/CSA), flame retardancy, and protection against coolants or washdown chemicals.
- Signal Protocol: Ensure the feedback cable is rated for the specific encoder type, such as SSI, EnDat, or Drive-CLiQ.
- Length & Voltage Drop: For long runs (over 20m), verify the gauge (AWG) is sufficient to prevent voltage drops that can cause encoder errors or torque loss.
1 product · ABB
Frequently asked questions
What is the difference between a servo power cable and a feedback cable?
Servo power cables carry the high-voltage electricity required to drive the motor's windings, often include a brake pair, and require heavy shielding. Feedback cables (or encoder cables) transmit low-voltage signals (TTL, HTL, or serial data) from the motor to the drive to communicate position and speed. Mixing these cables or using unshielded alternatives can lead to signal interference and "ghost" faults.
How do I choose between static and high-flex servo cables?
In static applications, standard PVC or PUR jacketing is sufficient. However, for continuous-flex applications like cable tracks or robotic arms, you must use "high-flex" or "drag chain" rated cables. These utilize finer copper stranding and specialized insulation materials to prevent internal wire breakage caused by repetitive bending.
Which communication protocols do these feedback cables support?
Modern servo systems often utilize proprietary or high-speed serial protocols. Common standards include EnDat (Heidenhain), Hiperface (SICK), BiSS, and Drive-CLiQ (Siemens). It is critical to ensure the feedback cable pinout and shielding match the specific protocol required by your drive and motor.
Can I use a single cable for both power and feedback?
Yes, many manufacturers offer "Single Cable Technology" (SCT) or "One Cable Connection" (OCC). Examples include Allen-Bradley Kinetix VP motors and Beckhoff OCT systems. These combine power, brake, and digital feedback into a single hybrid cable to reduce installation time and footprint.
Are servo cables interchangeable between different brands?
While connectors often look similar, pinouts are rarely universal between brands. For example, a Siemens SINAMICS cable will not work with an Allen-Bradley Kinetix drive without custom pinning. Always match the cable to the drive manufacturer's specific catalog number or use a verified cross-reference tool for aftermarket replacements.