MCT8316A: Motor Speed in Open Loop

Hi Jason,

One of our MCx experts will give you a reply tomorrow!

Thanks,
Aaron

Hi Jason,

Thanks for posting your question in MD forum. It is possible to limit the motor speed by enabling speed loop. When the speed loop is enabled, motor spins in closed loop at the configured maximum speed at 100% duty cycle. For example, with speed loop enabled, if the maximum speed is configured to 1000 Hz, motor spins at 1000 Hz at 100 % duty cycle and 500 Hz at 50% duty cycle. 

In the MCT8316A GUI home page, click "View all tuning settings". Maximum speed and speed loop can be configured in the "Control configuration - Closed loop" as shown in below screenshot.

Regards,

Vishnu

Hi Vishnu!

Thanks for your information, and I would like to know more about the motor behavoir before it goes into closed loop, since we can control the motor speed effectively by the speed loop function.

My motor always accelerates to a much faster speed in open loop, so I decrease the open loop acceleration and adjust many other parameters. However, it still runs too fast.

In other words, I cannot control my motor speed all the time after it begins spinning. How can I control the speed when it is still in open loop?

Sincerely,

Jason,

Decreasing the open loop acceleration coefficients A1 and A2 should bring down the open loop acceleration. In the GUI homepage, can you click "Start Guided tuning" and go to "Essential controls"->"Recommended default values" and select "Slow acceleration" or "Ultra slow acceleration" under the Application type drop down and  click "Restore recommended values"?

Regards,

Vishnu