Kübler 8.5868.1231.3112 Absolute Multiturn Encoder

The Kübler 8.5868.1231.3112 is a high-performance absolute multiturn encoder from the Sendix F5868 series, manufactured by Kübler Group, a German specialist in industrial sensor technology. This encoder provides absolute position feedback over multiple revolutions without requiring battery backup or external memory, delivering reliable position data for motion control systems, servo drives, and automated machinery. The encoder features a CANopen interface compatible with DS406 protocol, a 6 mm solid shaft, and a robust design rated for IP65 environmental protection.

Absolute Multiturn Technology

The 8.5868.1231.3112 utilizes optical sensing technology to achieve absolute position measurement. The singleturn function measures the angular position within one revolution with 16-bit resolution, providing 65,536 unique positions per revolution. The multiturn function extends the absolute measurement range by counting full revolutions of the shaft, using a gear-driven mechanical counter that operates without battery power. The multiturn range provides 12-bit resolution, allowing the encoder to track up to 4,096 revolutions (2^12) from a reference home position. The total resolution of the encoder is 28 bits, combining the singleturn and multiturn information. This absolute measurement principle ensures that the encoder outputs a unique position value for every shaft position throughout its range, even after power loss or mechanical movement while de-energized.

CANopen Communication Interface

The encoder communicates via CANopen, a CAN-based higher-layer protocol standardized according to CiA DS301 and DS406 for encoder devices. The CANopen interface supports the encoder profile according to CiA DS406, which defines the object dictionary structure for absolute encoders, including parameters such as resolution, scaling, preset values, and operating modes. The encoder can be configured as a Class 2 device supporting both polling and cyclic communication modes. The communication baud rate and node ID are configurable via the CANopen network. The DS406 profile includes objects for singleturn position, multiturn position, and total position, allowing the controller to retrieve the full 28-bit absolute position using standard CANopen read commands.

Resolution and Accuracy

The 16-bit singleturn resolution provides 65,536 steps per revolution, representing a theoretical angular resolution of approximately 0.0055 degrees. The accuracy of the encoder is determined by the optical sensor alignment and the mechanical precision of the code disc and reading head. The 12-bit multiturn tracking counts revolutions using a mechanical gear train independent of power supply, preserving the revolution count when the encoder is de-energized. The total position reported by the encoder is a composite of the singleturn angle and the multiturn revolution count, allowing the drive or controller to determine absolute machine position without homing after power-up.

Mechanical Design and Shaft Configuration

The 8.5868.1231.3112 features a solid shaft design with a diameter of 6 mm and a shaft length of 10 mm. The solid shaft configuration requires the encoder to be mounted in a stator coupling or directly coupled to the drive shaft using a flexible coupling. A clamping flange is provided for mounting, with appropriate bolt hole pattern dimensions per manufacturer specifications. The encoder housing is constructed from robust materials with high resistance to shock and vibration. The Sendix series incorporates the patented Safety-Lock design, which ensures high resistance to shock and vibration by positively locking the bearing in the housing even under extreme conditions. This design prevents bearing displacement and maintains optical alignment under mechanical stress.

Electrical Specifications

The encoder operates from a wide supply voltage range of 10 to 30 V DC, allowing direct connection to 24 V industrial control systems or 12 V battery-powered equipment. Power consumption is modest, and the encoder provides reverse polarity protection to prevent damage from incorrect wiring. The CANopen interface signals are differential CAN_H and CAN_L lines, requiring termination resistors at the ends of the CAN bus segment. The encoder is connected via an M12 connector with 5 pins arranged in a male, axial outlet configuration. This connector type is standard for industrial encoders and allows quick connection and disconnection without re-wiring. Output circuitry is short-circuit protected and provides ESD protection to withstand industrial electrical noise.

Environmental Specifications

The encoder is rated IP65 for ingress protection, meaning the housing is dust-tight and protected against water jets from any direction. This rating allows the encoder to be installed directly on machinery in industrial environments without requiring an additional enclosure. Operating temperature range is -40°C to +85°C, supporting deployment in outdoor installations, cold storage facilities, or machinery subject to high ambient heat. The wide temperature range also accommodates applications where the encoder is exposed to temperature cycling or occasional high-temperature cleaning processes. Vibration and shock resistance are specified according to applicable industrial standards for encoders used in servo drives and heavy machinery.

Applications and Suitability

The 8.5868.1231.3112 encoder is suited for a variety of industrial applications requiring absolute position feedback. Typical installations include servo motors and drives in CNC machine tools, packaging machinery, printing presses, and robotics. The multiturn absolute functionality is particularly valuable for applications where the equipment may be moved while powered down, as the encoder retains position information and the controller can resume operation without homing. The CANopen interface enables the encoder to be integrated into networked control architectures with multiple axes, sharing the communication bus with other CANopen devices such as drives, I/O modules, and HMIs.

Diagnostic and Configuration Features

The encoder includes diagnostic capabilities that can be accessed via CANopen. The object dictionary contains status information such as internal temperature, supply voltage monitoring, and communication error counters. The encoder supports configuration of parameters such as scaling factor, preset position, and operating mode via SDO (Service Data Object) messages. The encoder can be configured to operate in polled mode, where the controller requests position data as needed, or in cyclic mode, where the encoder autonomously broadcasts position data at a configured interval.

Installation and Connection

Installation requires mounting the encoder on a rigid bracket or motor flange with accurate alignment to the driven shaft. The solid shaft must be coupled to the drive shaft using a flexible coupling that compensates for angular and parallel misalignment. The clamping flange is secured with bolts torqued to manufacturer specification. The M12 connector is mated with a corresponding M12 cable assembly, which must be ordered separately. The CAN bus must be terminated with 120-ohm resistors at both ends of the bus segment to prevent signal reflections. Configuration of the node ID and baud rate is performed via LSS (Layer Setting Services) or by default settings if not configured.