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MCT8316AEVM: How to set low speed?

Kenji
Intellectual 530 points
Part Number: MCT8316AEVM
Other Parts Discussed in Thread: MCT8316A,

Hi Team!

I'm working on MCT8316AEVM (MDO38A1-002) with MCT8316A_GUI tool.
I want to know how to set the low speed.

In my motor environment, the low speed is about 3300 rpm.
I changed the speed using I2C or analog, but the speed will not drop below this speed.
I want to test the lower speed limit.

  • 0
    TI__Mastermind 24415 points

    Hi Kenji,

    Can you check if the speed loop is enabled? Also, can you check SPD_LOOP_V_MIN[10:8] in CLOSED_LOOP3 register ?

    Regards,

    Vishnu.

  • 0 in reply to Vishnu Balaraj
    Intellectual 530 points

    Hi -san

    By setting CLOSED_LOOP_3, I could rotate the motor at a speed of 3000 rpm or less.

    The rotation does not seem to be stable.

    The following video is the rotation at 700 rpm.
    Actually, I don't rotate it below 1000 rpm, is there a setting for stabilize it?

  • +1 in reply to Kenji
    TI__Mastermind 24415 points

    Kenji,

    Can you adjust the speed loop Kp and speed loop Ki? 

     

    Regards,

    Vishnu

  • 0 in reply to Vishnu Balaraj
    Intellectual 530 points

    Hi -san

    The closed loop also controls the speed, isn't it?
    Ok, I will try thank you.

  • +1
    TI__Prodigy 530 points

    Hi Kenji,

         Does your application demands closed loop speed control?. If not you can use the Min duty cycle in MOTOR_STARTUP2 configuration to adjust how low duty cycle you can set to spin your motor. Setting very low min duty cycle and then setting lower Target speed can give you lower speed as supported by motor. 

        If you enable the Closed loop , then the output speed is fraction of the Maximum speed in CLOSED_LOOP4 configuration. In addition you may have to tune the PI loop to achieve stable performance, To achieve stable but with slow response, you can choose to set Kp, Ki values to very low and gradually increase based on the requirement.

    Pavan.

  • 0 in reply to Venkata Pavan Mahankali
    Intellectual 530 points

    Hi -san

    Intended to write open loop, I wrote closed loop.
    I made you confused.

    Thank you for the information