MCT8316ZTEVM: Motor Settings and Calculations

Markus Strauss

Part Number: MCT8316ZTEVM
Other Parts Discussed in Thread: MCT8316Z

Hi there

I'm using MCT8316ZTEVM an I use a motor that has 7 pole pairs.


In the GUI I can only choose between 6 or 8 pole pairs.
What can I do to set the number of pole pairs to 7?
In which register is the number of pole pairs stored?

Best Regards
Markus

over 2 years ago

0 Aaron Barrera over 2 years ago

TI__Mastermind 26046 points

Hi Markus,

I fixed the GUI right now so you can choose 7 pole pairs.

Thanks,
Aaron

0 Markus Strauss over 2 years ago

Prodigy 20 points

Hi Aaron

now I can choose 7 pole pairs, but the motor does not turn.

0 Markus Strauss over 2 years ago

Prodigy 20 points

Hi Aaron

now I can choose 7 pole pairs, but the motor does not turn at any time.

do I have to do anything else?

Best Regards

Markus

0 Aaron Barrera over 2 years ago in reply to Markus Strauss

TI__Mastermind 26046 points

Hi Markus,

Is the red light lit up when you plug in the EVM? When you power on the supply, do the VM and VBK LEDs light up green?
Do you have the jumper to provide the PWM from the MSP set to PWM_MSP? Are the jumpers connected to provide the PWM to the MCT8316Z device?
Is the DRVOFF switch set to "DRV ON"?

Thanks,
Aaron

0 Aaron Barrera over 2 years ago in reply to Aaron Barrera

TI__Mastermind 26046 points

Also please follow the MCT8316ZTEVM Getting Started video: https://www.youtube.com/watch?v=v7TKM4VL-rw

Thanks,
Aaron

0 Markus Strauss over 2 years ago

Prodigy 20 points

Hi Aaron

everything is as you said.

With the fist GUI version where I could not set the number of pole pairs everything was working fine.

But now when I connect the GUI it does not connect -> COM6:9600 waiting for data ...

When I press the RST button on the PCB the GUI gets connected an the motor makes a short move.

Now I turn on the potentiometer an the motor starts moving.

But no matter what number of pole pairs I enter, the motor always turns at the same speed.

In my opinion, the speed of the motor should change if I change the number of pole pairs.

What do you say to this?

Best Regards

Markus

0 Aaron Barrera over 2 years ago in reply to Markus Strauss

TI__Mastermind 26046 points

Hi Markus,

Changing the number of pole pairs in the firmware only recalculates the estimated motor RPM. The number of motor pole pairs on your motor is fixed, so the speed will not change with the pole pair drop down selection since the only dependency for motor speed that is controllable is the Hall sensor feedback frequency (FGOUT). The equation for calculating motor speed is:

RPM = (60 * fe) / (# of pole pairs)

where fe is the electrical frequency, This is calculated from FGOUT (XOR of Hall sensor feedback) from the MCT8316Z.

Thanks,
Aaron

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MCT8316ZTEVM: Motor Settings and Calculations