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DRV8834: Stepper Motor Missing Steps

Nipam Bhavsar
Intellectual 620 points
Part Number: DRV8834

Hello All,

Greetings !!!

I am currently working on one project in which we are using DRV8834 motor driver IC and Portescap stepper motor(having 15 degree angle, 400 PPS and 3.6 Volt). The problem that we are facing is related to missing steps when Motor is running in forward and backward direction. We are using Indexer mode configuration. I am describing the problem in detail.

1) Configured DRV8834 to Full step (M0 and M1 are configured to Low Level). but the problem is same, missing the steps of stepper motor.

2) Configured DRV8834 to Half step (M0 is configured to High Level and M1 is configured to Low Level). but the problem is same, missing the steps of stepper motor.

I checked stepper motor steps in debug window but it shows the same steps value every time but still I am getting missed steps. In code I put 2 ms delay also after wake-up from sleep. I have attached schematic screenshot of DRV8834 driver IC.

Please help me to resolve this problem as I am stuck in this since many days.

Thanks,

Nipam

  • 0
    TI__Guru 56650 points

    Nipam,

    If the winding current doesn't reach the regulation point, that could cause the missing step.
    Example: If xVREF is 2 V (as it would be if xVREF is connected directly to VREFO) and a 100-mΩ sense resistor is used, the chopping current will be 2 V / 5 × 100 mΩ = 4 A.
    What is the full winding current do you want? Could you measure the winding current to find out which step is missing?

    Also, the decay mode setting can affect the winding current waveform. The current setup is 50% OF PWM CYCLE IS FAST DECAY. After we have winding current waveform, we may be able to adjust the decay mode to get a better result.

  • 0 in reply to Wang5577
    Intellectual 620 points
    Dear Wang Li,

    Thanks for your kind response.

    Apology for delayed response as I didn't get this notification over the mail.

    I will check all your suggestions and get back to you for the answers. About decay mode, we didn't configure decay mode period in Hardware and Firmware as well because we require the same speed of the stepper motor during in running mode.

    Thanks & Regards,
    Nipam
  • 0 in reply to Nipam Bhavsar
    TI__Guru 56650 points
    Nipam,

    I am going to close this thread. If you have any update, you can reopen it by putting update in this thread.
  • 0 in reply to Wang5577
    Intellectual 620 points

    Dear Wang,

    Sure, I resolved this problem 2 days before. The problem is in code in putting DRV8834 in sleep mode. Currently I am not facing any problem with missing steps. I will inform you if any problem will come.

    Thanks for your responses on the same.

    Thanks,

    Nipam

  • 0 in reply to Nipam Bhavsar
    TI__Guru 56650 points
    Nipam,

    Great! Thank you for your update.