Audible noise in Stepper driver A3977

Discussion in 'Embedded Systems and Microcontrollers' started by g_shyam1682, Feb 20, 2010.

  1. g_shyam1682

    Thread Starter New Member

    Jan 25, 2010
    5
    0
    Hi friends

    I have one stepper driver with IC A3977
    When i rotate Stepper motor or vary the speed of Stepper motor, it produce Audible noise of current in winding.

    so guys do you have any suggestion to reduce this noise.
    Any one have any idea or link,
    Please tell me, Suggestion is highly appreciated
    Thanks in advance
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    Can you post the current schematic?
    With that at hand we can have a look if this needs some adjustment.

    Greetings,
    Bertus
     
  3. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Noise is normal in PWM motor drives. The usual way to make it inaudible is to increase the frequency above 20KHz.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Markd77 suggestion is the solution. The windings of the motor and/or losse metallic parts vibrate due to the change in the magnetic field. If the magnetic filed changes with a frequency of less than 20kHz then the windings vibrate at this frequency (or close to it). This is in the audible range and causes this annoying noise.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    I read this to be a stepper motor - it won't drive with PWM.
     
  6. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    It is all in the datasheet as usual.....

    So try a different decay mode.....


     
    Last edited: Feb 20, 2010
  7. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    the A3977 implements a PWM to drive the stepper ...


     
  8. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    A3977 has built in PWM :

    external PWM not necessary, only have to provide step and direction logic controls for this IC.....
     
  9. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    We have already cover this topic, but yes, PWM is necessary for microstepping, and it is built into the A3977..... so NO EXTRENAL PWM CIRCUIT IS NEEDED FOR USING THE A3977 AS A MICROSTEPPING STEPPER CONTROLLER.

    The OP's problem with audible noise is not due to the PWM or the microstepping, it has to do with the current decay scheme he selected to used, if he uses the mixed-decay mode, this might reduce the audible "noise"...

     
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