DRV8889-Q1: DRV8889-Q1 stall detection issue

Hello Alex,

Thank you for posting in this forum. You mentioned the motor rated current is 0.3 A but the GUI setting is much lower, 0.131 A, what is the reason? 0.42 x 31.25% = 0.131. Did you try setting for 0.3 A, Torque DAC = 100%? Can we get a capture of the current waveform at the target speed 21666 PPS 1/32 uSteps? 

What was the supply voltage used for the EVM motor supply? Thank you.

Hi Murugavel,

Murugavel4637 said:

You mentioned the motor rated current is 0.3 A but the GUI setting is much lower, 0.131 A, what is the reason? 0.42 x 31.25% = 0.131. Did you try setting for 0.3 A, Torque DAC = 100%? 

The motor was tested without load, 0.42 x 31.25% was enough to rotate the motor. I also tried to set Torque DAC to 100%, but the motor would vibrate and make noise. BTW, I debugged this issue with different parameters, this issue seemed to be related to the speed, and I was not sure if it was related to resonance.

Unfortunately, due to mechanical constraints, the speed is designed to be limited to less than 120RPM. I'll be very gratefull if you could use your expertise to help analyze this issue.

You could find more information of this motor in the following URL:

https://www.moonsindustries.com/p/nema-14-smooth-hybrid-stepper-motors/14hk0405n-000004611110014999

The current motor we chose was 14HK0405N, should we change to 14HK0406N, 14HK0407N, or 14HK0408N for stall detection?

Murugavel4637 said:

Can we get a capture of the current waveform at the target speed 21666 PPS 1/32 uSteps? 

I measured the phase current‘s waveform last week, sorry for forgetting to capture the waveform of speed 21666 PPS 1/32 uSteps. The other waveforms are as following:

(1)9666 PPS(close to 21666 PPS under 1/32 uSteps), 1/16 uSteps, 0.42A, 50% Torque DAC

(2)3200 PPS, 1/32 uSteps, 0.42A, 50% Torque DAC

Murugavel4637 said:

What was the supply voltage used for the EVM motor supply?

12V.

Thanks,

Alex

Hi Alex,

Thanks for the additional details. While resonance affects full-step and half-step I don't anticipate severe resonance issues at 1/16 or 1/32 steps. The current waveforms you shared looks clean. This seems like a reasonable setting, "9666 PPS(close to 21666 PPS under 1/32 uSteps), 1/16 uSteps, 0.42A, 50% Torque DAC". With these settings what was the torque count, still 0?

Could you also please capture current waveforms in 1/16 , 1/32 steps while there is severe vibration? 

Alex Wang said:

The current motor we chose was 14HK0405N, should we change to 14HK0406N, 14HK0407N, or 14HK0408N for stall detection?

Lower DCR and lower inductance would give better results for stall detection. It will make sense to compare 14HK0407N vs 14HK0405N. I've never had the opportunity to test with 0.9 deg/step motors so far. I'll try to procure one of these although it might take some time for me to get one of these. 

Is it possible to share some information about the end application? Thank you.

Regards, Murugavel

Hi Murugavel,

Murugavel4637 said:

While resonance affects full-step and half-step I don't anticipate severe resonance issues at 1/16 or 1/32 steps.

Yes, from the information found on the Internet, 1/16 or 1/32 microsteps should solve the resonance phenomena. This issue is strange...

Murugavel4637 said:

With these settings what was the torque count, still 0?

Yes, still 0. I guess the high resistance and the low speed lead to low Back-EMF?

Murugavel4637 said:

Could you also please capture current waveforms in 1/16 , 1/32 steps while there is severe vibration? 

Sorry, our company's laboratory resources must be reserved one month in advance, so I could not capture the related waveform for now. But last week I also observed the waveforms while there was severe vibration, it seemed that they were normal, the difference was the current magnitude when applying different Torque DAC under the same speed.

Murugavel4637 said:

t will make sense to compare 14HK0407N vs 14HK0405N. I've never had the opportunity to test with 0.9 deg/step motors so far. I'll try to procure one of these although it might take some time for me to get one of these. 

OK, due to the tight project timeline, I would ask our supplier to replace the motor with 14HK0407N directly. And thanks a lot if you could help to test the motor with 0.9 deg/step.

Murugavel4637 said:

Is it possible to share some information about the end application?

The end application is to rotate the screen in limited time(3 seconds) and limited range(not defined, but it would not be very big).

Thanks,

Alex

Hi Alex,

Thanks for getting back to us.

Alex Wang said:

Yes, still 0. I guess the high resistance and the low speed lead to low Back-EMF?

Yes we've seen this in the past. Low speed has a greater impact with not enough BEMF for good SNR for the stall detector. Here's the application note, https://www.ti.com/lit/an/slvaei3/slvaei3.pdf.

Alex Wang said:

Sorry, our company's laboratory resources must be reserved one month in advance, so I could not capture the related waveform for now. But last week I also observed the waveforms while there was severe vibration, it seemed that they were normal, the difference was the current magnitude when applying different Torque DAC under the same speed.

Understood. If the waveform is clean I do not expect severe vibration. I've not tried a 0.9º stepper so far.

Alex Wang said:

OK, due to the tight project timeline, I would ask our supplier to replace the motor with 14HK0407N directly. And thanks a lot if you could help to test the motor with 0.9 deg/step.

Sounds good. I hope this resolves the issue. 

Regards, Murugavel

Hi Murugavel,

Thanks, I'll come back to you when the 14HK0407N motor arrives, which might take half a month.

Thanks,

Alex

Hi Alex,

Thanks. I've placed an order for getting couple of these steppers. I hope they'll arrive within a couple of weeks. Let's connect once it arrives. 

Regards, Murugavel 

Hi Murugavel,

OK, thanks a lot for your great support!

Thanks,

Alex

Hi Murugavel,

During the usage of DRV8889 and 14HK0405, I encountered another strange issue. I posted in another new thread, could you help to analyze? Thanks!

Thanks,

Alex

Hi Alex,

Yes, I will do, thanks.

Regards, Murugavel 

Hi Murugavel,

Thanks a lot for your response based on14HK0406N stepper.

Our order on 14HK0407N also took longer time than we thought, but the good news is 14HK0407N stepper will arrive next week. And I'll come back to you then.

Thanks,

Alex

Hi Alex,

Sounds good, thanks.

Regards, Murugavel