Detect the motor is blocked by the OCD flag

[GLeco.1]

Hello,

I thought to use the OCD flag of the L6474 STATUS register to detect the end of the mechanism’s motion when the stepper motor is blocked.

But we have some trouble doing this.

If the current in the  OCD_TH is less than the current in TVAL, the OCD flag is set at the beginning of the motion.

If the current in the  OCD_TH is greater than the current in TVAL, the OCD flag is never set when the motor is blocked.

Do you think it is possible to detect when the motor is blocked by using the OCD flag and the OCD_TH register.

Thanks for any advices 

[Cristiana SCARAMEL]

Hello @Community member​ and welcome to the ST Community.

The OCD cannot be used for stall detection because the device keeps the current under control even if the motor is in stall condition.

The OCD is able to detect anomalous condition of the load like:

• wrong wiring of the motor
• short of the power outputs

Unfortunately it is not possible to implement a stall detection using the L6474.

I hope this post can help you; if so, consider to mark it as best answer by clicking the label "Select as Best".

[GLeco.1]

Thanks Cristiana,

If we replace the L6474 by the L6470 which is a voltage driver and has the specific STALL registers, could we achieve our needs. 

Regards

[Cristiana SCARAMEL]

Hi @Community member​,

I confirm that the L6470 motor driver offers a sensorless motor stall detection.

In the linked product page you can find all the documentation and available tools.