[DRV8824-Q1] How to make the Stall function with MCU

Hi Nate,

Does the customer want to use the stall as an end of travel or an actual stall?

The device should support 800mA pk-pk at 800pps. This depends on VM voltage and motor parameters.

Sense resistor is set based on equation 1 of the datasheet.

Hi Rick,

Thanks for very quick response.

Actually, What is difference between stall as an end of travel and actual stall??

The device supports 800mA @ 800pps is very good new.

As I understand, The VM voltage is 12V. 

What do you need to check the motor parameters? you mean the motor resistance/inductance?

BRs,

Nate

Hi Nate,

A stall can occur at any time, and can be due to accelerating too quickly, running the motor too fast, or encountering an unexpected load increase.

End of travel is usually defined as hitting an end stop, which will cause a stall. An example is a 3D printer. At the beginning of the print, the extrusion head is moved to the 0,0,0 origin. This origin is usually detected by mechanical limit switches or hall sensors.

Many customers want stall detection to detect this end stop. Others want stall detection to detect abnormal behavior during operation.

Please provide the motor resistance/inductance/voltage/current ratings. If all are not available, please provide the ratings that are available.

Hi Rick,

Thanks for explanation.

The motor spec : Resistance is 12ohm / Inductance is 4.2mH / voltage is 5V / Current is 0.42A 

I have tried test with GUI

current setting - 0.8A / Slow Decay / 720 pps. / input voltage 12V / 

at this situation, sound noise is occured at motor. do you know why it happened noisy sound?

Regards,

Nate

Hi Nate,

I don't know why there is noise but the settings do not seem correct.

For a motor of 0.42A, you should set the GUI current at either .42A. This is the specified current through the motor.

I would recommend starting with fast decay also.

You should also examine the current waveform to determine if you are getting the current that is being set.

Hi Rick,

As you suggested, I set up fast decay, 0.42A,/ 720pps/Full step/ Accel. rate 200 / Time base 2.  but noise is still occured.

but customer spec is 0.8A, because this is for low-temperature operation test.

I have several questions.

Q1) what is best Acceleration rate and time base value?

When I tune both value, noise same exist...

Q2) As below current waveform of A+ from motor output, below what is red circle component?

Please let me know what can I do any way.

Best Regards,

Nate Lee

Hi Rick,
This is gentle reminder.
Please check my request.

BRs,
Nate

Hi Nate,

Q1) what is best Acceleration rate and time base value?

When I tune both value, noise same exist...

What type of noise are you experiencing (audible, electrical, mechanical)?

The acceleration rate depends on the motor manufacturers specifications and load.

Q2) As below current waveform of A+ from motor output, below what is red circle component?

The red circle component is the current ripple during fast decay. This can be seen if you zoom in and compare the output with the current. The current will reach the trip point and then decay for the remainder of the PWM cycle. The next PWM cycle will insert current into the winding until the trip point is reach and the decay mode will begin again.