MCT8315Z: Problem with change DIR

Michele Bacchereti

Part Number: MCT8315Z

Tool/software:

I have this problem: sometimes after change DIR from 0 to 1 or from 1 to 0 to change motor direction the motor stop it self for a long time (it seems more or less 1 sec) also if my uC send a PWM different from 0.

No Fault is rise from the driver.

There some limitation that I have not read in the datasheet?

6 months ago

0 Michele Bacchereti 6 months ago

Prodigy 30 points

In the DS there is this NOTE:

Note
Texas Instruments recommends motor direction (DIR) change when the motor is stationary

But I have to change DIR during the movement.

0 Venkatadri Shantaram84961 6 months ago in reply to Michele Bacchereti

TI__Mastermind 23542 points

Hi Michelle,

Changing direction on the fly is not recommended. This is because to change direction motor has to be decelerated safely and then change direction.

This is not programmable and sudden change in direction can put kinetic energy back to supply causing over voltage or damage.

Instead, you can break and then change direction or stop motor and then start in other direction.

Thanks and Best Regards

Venkatadri S

0 Michele Bacchereti 6 months ago in reply to Venkatadri Shantaram84961

Prodigy 30 points

It is right.

I have a spring load and I push it with the linear trasmission after the motor.

DEveloping a position control PID I have some issue every change direction where I am near the target position.

In this case I have many change of direction...

Is there any way to avoid this behavior of the driver?

0 Venkatadri Shantaram84961 6 months ago in reply to Michele Bacchereti

TI__Mastermind 23542 points

Hi Michelle,

Let me relook into this and get back to you.

Thanks and Best Regards

Venkatadri S

0 Venkatadri Shantaram84961 6 months ago in reply to Venkatadri Shantaram84961

TI__Mastermind 23542 points

Hi Michele,

I missed to replay again, how is the progress?

During direction change there can be some fault and for hardware variant default 500ms retry time + detection time upto 1s

Thanks and Best Regards

Venkatadri S

0 Michele Bacchereti 6 months ago in reply to Venkatadri Shantaram84961

Prodigy 30 points

I this moment every times that I have to change direction I send a 30us trigger on DRVOFF.

This means a 120/130us of Current Motor off but then the driver operate normally.

0 Venkatadri Shantaram84961 5 months ago in reply to Michele Bacchereti

TI__Mastermind 23542 points

Hi Michele,

That is cool, hope you see proper re synch.

Thanks and Best Regards

Venkatadri S

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MCT8315Z: Problem with change DIR