Open and close loop stepper control

Used In:

  • Any stepper motor application (close and open loop)
  • Any brushless motor application without feedback

A stepper motor is a brushless, synchronous electric motor that converts digital pulses into mechanical shaft rotation.

Each stepper motor pulse turns its shaft by a one-step rotation angle and aims for the motor shaft rotation to be proportional with the input pulse command.

Step motors are used every day in both industrial and commercial applications due to their low cost, high reliability, high torque at low speeds and a simple, rugged construction that operates in almost any environment.

Elmo’s intelligent servo drives allow you to control a:

  • 2 or 3 phase stepper motor
  • 2 or 3 phase brushless motor in stepper mode

Our Exclusive Gold Bell servo drive allows control of all of the above and a 2 phase stepper motor.


Typical stepper motor internal structure:

Elmo’s unique development for enhanced motor performance is two stepper functions:

  • Stepper Open loop torque– Sets the open loop torque for 3 different movement types;
    • No movement
    • Movement at certain speed without acceleration
    • Movement with some acceleration
  • Stepper Feed forward– adds
    • Gain proportional to the velocity
    • Acceleration
    • Phase advance

The results are a smooth system with better performance.

Design Features

  • Open and close loop stepper motor control
  • Provides top performance – High power density stepper motor drive
  • Supports any 3 brushless motor to rotate without any feedback (open loop)
  • Open loop torque – Enables adding current in 3 motor situations
    • Standstill
    • Constant velocity
    • Acceleration
  • Improves stepper motor performance – Feed forward

For more information please contact our motion control experts.

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