Understanding Servo Cable Assemblies
Servo cable assemblies are pre-terminated connections between compatible servo drives, motors and feedback devices. Depending on the system, an assembly may carry motor power, brake circuits or encoder and resolver signals. Supplying the specified cable and connectors together reduces termination work during machine building and makes repeat orders easier to manage.
The right assembly depends on more than cable length. The motor and drive references, connector and pin configuration, electrical requirements, shielding and installation conditions must match. A cable described as flexible is not necessarily suitable for repeated movement in a cable chain.
LAPP offers assemblies compatible with selected Siemens®, Rockwell Automation® and SEW-EURODRIVE® systems, including options for fixed installations and dynamic applications. LAPP Australia can also review custom length, labelling, prototype and repeat-production requirements through our harnessing team.
How Servo Cable Assemblies Support Motion Control
A servo system operates as a closed control loop. The drive sends electrical power and movement commands to the servo motor. A feedback device measures the motor position or speed and returns that information to the drive. The drive then adjusts the motor output to follow the commanded movement.
This connection places different demands on each cable. Motor power conductors must carry the required current. Feedback and encoder circuits must transmit accurate signals in an electrically noisy environment. Screening, connector compatibility and correct earthing help manage electromagnetic interference around motors, drives and switching equipment.
Main Types of Servo Cable Assemblies
| Assembly type | Primary function | Typical use |
|---|---|---|
| Motor power assembly | Carries electrical power from the servo drive to the motor. | Servo motors in automated machinery |
| Power with brake assembly | Carries motor power and conductors for an integrated holding brake. | Vertical axes, lifting or positioning systems |
| Feedback assembly | Returns motor position, speed or status information to the drive. | Closed-loop motion control |
| Encoder or resolver assembly | Connects the motor feedback device to the drive or controller. | Accurate speed and position control |
| Hybrid assembly | Combines power and signal functions within one cable construction where supported by the drive system. | Space-saving machine layouts and selected single-cable systems |
Where Servo Cable Assemblies Are Used
Servo assemblies support industrial equipment that needs accurate, repeatable and coordinated movement.
Benefits of Ready to Connect Servo Assemblies
Factory-assembled servo cables reduce the amount of connection work completed during machine build, commissioning and maintenance. Benefits can include:
- Faster machine wiring and installation
- Less cutting, stripping, crimping and connector assembly on site
- Consistent connector and pin configurations
- Reduced risk of termination and wiring errors
- Factory-assembled and tested connections
- Clear identification and production traceability
- Fewer separate components to purchase and manage
- Simpler replacement during planned maintenance or breakdowns
- Repeatable assemblies for OEM and series production
The commercial value depends on the machine design, production volume and work removed from the assembly process. For OEMs building repeated machines, standardised assemblies can reduce build variation and make procurement easier to manage.
Fixed Flexible and Continuous Movement
The word flexible does not automatically mean a cable is suitable for continuous movement. The cable construction should match how the machine moves throughout its operating life.
| Movement class | What it means | Common applications |
|---|---|---|
| Fixed installation | Cable remains in position after installation, with limited movement during maintenance. | Control cabinets, fixed motor connections and static machine wiring |
| Flexible machinery connection | Cable moves occasionally or repeatedly without the controlled bending pattern of a cable chain. | Machine sections, movable panels and service loops |
| Continuous flexing | Cable completes repeated bending cycles inside a cable chain or similar guiding system. | Robots, gantries, machine tools and automated handling systems |
PVC and PUR Servo Assemblies
PVC servo assemblies are commonly used for fixed installation and selected flexible applications. They can offer a practical option where the cable is protected from demanding mechanical or chemical exposure.
PUR servo assemblies are often selected for dynamic machinery and cable-chain use. Depending on the product, PUR sheaths can provide improved resistance to abrasion, oil and mechanical wear. Sheath material alone does not confirm suitability for continuous flexing, so the product data, minimum bending radius and movement rating must be checked.
How to Choose a Servo Cable Assembly
Before selecting or requesting an assembly, gather the following information:
- Motor and drive manufacturer
- Exact motor and drive model or original cable reference
- Power, brake, feedback, resolver or encoder function
- Connector type, coding and pin configuration
- Required cable length
- Fixed, flexible or continuous-flexing installation
- Minimum bending radius, travel distance, speed and acceleration
- Operating temperature
- Exposure to oil, chemicals, moisture, abrasion or UV
- Required standards or approvals
- Quantity, labelling and repeat-production requirements
A complete manufacturer reference is the fastest starting point for replacement enquiries. For new machinery, the drive and motor data should be reviewed alongside the mechanical movement and operating environment.
How LAPP Can Assist
LAPP combines cables, connectors and assembly services within one product and technical support network. LAPP Australia can assist with both standard servo assemblies and application-based connection requirements.
Assemblies for Common Drive Systems
The LAPP Australia range includes ready-to-connect motor power, brake, feedback and encoder assemblies compatible with selected Siemens®, Rockwell Automation® and SEW-EURODRIVE® drive-system requirements. Common references and lengths are available online, with other requirements reviewed by the technical team.
Support for Fixed and Dynamic Applications
Options are available for fixed installation, flexible machinery connections and continuous movement in cable chains. For example, selected Siemens-compatible ranges include 6FX5002 PVC assemblies for fixed installation and 6FX8002 PUR assemblies for highly dynamic applications.
Local Technical and Assembly Support
LAPP Australia's local harnessing capability supports component selection, prototypes, labelling, testing and repeat production. Australian-made harnessing solutions are supported by local communication and documentation, with testing completed to customer and industry requirements.
Cable and Connector Portfolio
LAPP Australia stocks more than 5,000 parts and over one million metres of cable. Access to servo motor cables, encoder cables, circular connectors and cable-chain products gives the team a broad base for standard and application-driven enquiries.
Selection and Configuration Support
Customers can browse the online servo assembly range or provide the technical team with the motor model, drive reference, original cable designation, cable length and application conditions. LAPP also offers a servo cable configurator for compatible assembly selection where applicable.
LAPP Servo Cable Options
The wider LAPP portfolio includes servo cable assemblies for leading industrial drive systems and cables for static, flexible and cable-chain applications. Selected products provide screened constructions for EMC performance, oil-resistant PUR sheaths and hybrid designs carrying power and signals within one cable.
One example is ÖLFLEX® SERVO FD 796 CP, a screened hybrid servo cable for dynamic applications in cable chains and industrial machinery. Selected sizes are locally stocked. Product selection should be confirmed against the drive system, movement and environmental requirements.
Frequently Asked Questions
What is the difference between a servo cable and a servo cable assembly? +
A servo cable is supplied as cable without the final drive and motor connectors fitted. A servo cable assembly is supplied with the required connectors and termination already completed, making it ready for connection to compatible equipment.
What types of servo cable assemblies are available? +
Common types include motor power, power with brake, feedback, encoder, resolver and hybrid assemblies. The available functions depend on the motor and drive system.
Can a servo assembly replace the original drive manufacturer cable? +
A compatible assembly may replace an original cable when its electrical ratings, conductor arrangement, connectors, pin configuration, shielding and mechanical performance match the drive-system requirements. Confirm compatibility against the full original reference before ordering.
Are all flexible servo cables suitable for cable chains? +
No. A cable described as flexible may be suitable for installation and occasional movement without being rated for repeated bending in a cable chain. Check the cable-chain rating, minimum bending radius, travel distance, speed, acceleration and cycle requirements.
Why is screening used in servo assemblies? +
Servo drives and motors can create electromagnetic interference. A correctly designed screened cable and connector system helps control interference and protect power and feedback signal integrity. Installation and earthing practices remain part of the complete EMC design.
What information does LAPP need to identify an assembly? +
Provide the motor and drive manufacturer, exact model numbers, original cable reference, required length, assembly function and details of the movement and operating environment. Photos of the connectors and equipment labels can also help with identification.
Can LAPP support custom lengths and repeat production? +
Common references and lengths are available online. LAPP Australia can review other length, labelling, prototype and repeat-production requirements through its Harnessing Solutions team.
Get help selecting a servo cable assembly
Need help identifying the correct assembly? Send LAPP Australia your motor model, drive reference, existing cable designation, required length and application conditions.
Browse servo cable assemblies Discuss your application with LAPP Australia