• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 29 subscribers
  • Views 643 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8412 PWM help

Ivan Debelec
Intellectual 360 points
Other Parts Discussed in Thread: DRV8818, DRV8412, DRV8829, DRV8828, CONTROLSUITE

Hello,

I'm new at stepper motor control, and new at forum...

I'm working on bipolar NEMA23 3A stepper motor driver, and I worked with DRV8818 but it seems that DRV8818 was not strong enough to run that motor so i chose to go on DRV8412 driver...

As DRV8818 have simple interface (STEP input) i dont realy know how should I generate PWM for DRV8412...

I have read datasheet and I want to use mode 1: Dual full bridges (two PWM inputs each full bridge) or four half bridges with cycle-by-cycle current limit

At the moment i have C2000 Piccolo LaunchPad, and I'd like to control one motor using 4 PWM for DRV8412... I have seen that there is ControlCard with F28035 with program examples, and in near future i will probably use that, but i'd like to understand what i need on PWM inputs to make stepper move...

Can you please give me some explanation how my PWM should look like??? Is there some sequence which I should follow for making a movement in CW or CCW direction?? If PWM on input is not good will that destroy driver? 

If i want to get 2.8A from driver with CBC current limiting do I have to use 100kohm OC_ADJ resistor?

Thanks for answer...

  • 0
    TI__Mastermind 26065 points

    Hi

    If you use DRV8412, you need to do the current regulation using PWM and close loop current control. A strong MCU like C2000 is needed just as our DRV8412 C2000 kit.

    There are also other options like DRV8828/DRV8829. You need two for one motor.

    Also we have new solutions not released yet, you can contact TI sales for the information with DNA.

    Thanks.

    Wilson

  • 0 in reply to Wilson Zuo
    Intellectual 360 points

    I'm sorry, but i still dont get the point...

    I dont undestand that concept - how to control motor using PWM... How can I change motor direction? How can i count step number?

    When I was working with DRV8818 i have STEP input and DIR input... Now i have 4 PWM and i dont undestand the concept how motor is stepping?? Is there some internal sequencer which generate sequence on outputs??

    I know this is maybe stupid question but i need some literature where i can learn how to use PWM for stepper motor control...

    Thanks...

  • 0 in reply to Ivan Debelec
    Intellectual 360 points

    Hello again,

    during the weekend i read a lot about my problems so i have learned some new things...

    I suggest to TI that it will be great to have some application notes about controling steppers with PWM...

    If I use CBC mode, then I adjust current treeshold with OC_ADJ resistor, so if i want to get 2.8A from driver with CBC current limiting do I have to use 100kohm OC_ADJ resistor?

    Thanks...

    Regards,

    Ivan

  • 0 in reply to Ivan Debelec
    TI__Mastermind 26065 points

    Hi Ivan

    If you install TI controlSUITE, you will find the PWM micro stepping Doc"Microstepping.pdf" in DRV8412-C2-KIT package. It is a good material to learn how to apply PWM micro stepping method.

    If you want more info and support on this, I think you can post on C2000 forum.

    Thanks,

    Regards.

    Wilson

     

     

  • 0 in reply to Wilson Zuo
    Intellectual 360 points

    Hello again...

    Can you please post here pictures from PWM input on DRV8412 kit??? If is possible i'd like to see all 4 PWM inputs at speed of 100 rpm and current aprox. 2A...

    I'm trying to make my stepper move with C2000 Launchpad i get some rotation but sometimes i get some strange hitches... 

    Thanks...