Stepper motors are closer in performance to more complex servo drives. This is achieved with the new magnetic stepper kit, which can be integrated into commercially available motors as an easy-to-install feedback system. They provide absolute position data and multi-turn capabilities at an attractive cost - energy self-sufficient and maintenance-free.
The true classic: Stepper motors are one of the most popular and cost-effective basic components of open position control loops. Simple and compact DC motors are used in a wide range of applications, from small tools and equipment to printers and vehicles. In industrial environments, they are used, for example, for classical positioning tasks in machines or for quick pick and place processes.
Position with minimal steps
They are controlled by the stepwise rotating electromagnetic field of the stator coil: the rotor moves forward with a well defined step or angular offset with each pulse. Usually up to 200 steps per revolution, but 400 or more motors are also available. With a microstep operation, a resolution of less than 0.1 degrees can be achieved.
Although stepper motors can be placed in a positionless feedback system, often come with simple optical incremental encoders to train: the stepper motor has the same typical drawbacks from the low cost encoder. By detecting and providing angle values, they compensate for step losses, for example due to excessive load torque.
Stepper motor magnetic feedback system
Cologne sensor manufacturer Posital has been continuing to use the new stepper kit launched with the incremental kit. The magnetic feedback system introduced by SPS 2018 was originally designed for servo drives. The convenient mounting kit provides absolute and multi-turn functionality in an energy-independent, battery-free and computer-powered package that is tailored to the specific specifications of the stepper motor. The stepper kit significantly improves performance levels: results range from better concentricity, higher transparency in the control process, to higher quality for actual positioning tasks.
The kit can be installed in all common stepper motors. The specifications of the American Association NEMA (National Electrical Manufacturers Association) apply to specifications that traditionally determine the standardization of stepper drives. The design of the footprints and mechanical connections allows the Posital kit to be used as a direct replacement for classic incremental encoders. A ready-to-use stepper kit with M12 plug and JST connection and a 4 to 10 mm hub diameter for stepper motor upgrades to full absolute position control with multi-turn capability.
Small package, quick assembly
Absolute encoders can assign unique position values ​​to the travel and angular positions at any time and store them safely - even in the event of a power failure. When monitoring the 360-degree measurement range in a single-turn operation, multi-turn monitoring is performed by a large number of rotations.
The magnetic stepper kit features 17-bit single-turn and 16-bit multi-turn resolution, which packs all components in a compact electronic component with a diameter of 37 mm. The package is secured by two screws on the motor shaft. When the Hall sensor detects a single turn position by rotating the magnetic field, the rotation is recorded by a rotation counter that is self-sufficient in energy. Pulses from Wiegand wires made by Posital provide power for smart energy harvesting.
The book Tips "Industrial Sensors" introduces the development and practical application of the most important sensors. Through the measurement system, non-contact, because magnetic induction technology - in addition to permanent magnets - no moving parts, has strong impact resistance and vibration resistance, can resist dirt or moisture. If the motor shaft rotates briefly at a constant speed, an integrated electronic calibration function is sufficient. Record the individual characteristics of each engine and store them in the software. SSI and BiSS C can be used as an interface for two-way communication.
With the new stepping kit, Posital not only solves the OEM market, but also the main user: the inexpensive kit can be easily retrofitted and transforms a simple stepper motor into a powerhouse.
