Occurring malfunction case in use of DRV8880

HI Kawai-san,

What are the other inputs of the DRV8880 when you see this?
What is the step size?
What is ATE?
What is VREF, and the sense resistor?
What is TOFF?
What are the TRQ pins?

Hi Rick,

I use an evolution board (TIDA-00830 24V Stepper Motor Design with AutoTune™ TI Reference Design) after removed R3, R4 resister arrays.

Please confirm other states of the signals when I operate it.

step size -> I start the motor at 1000 pps and accelerate to 3000 pps. I maintain 3000 pps for a while and decelerate to 1000 pps before stopping the motor with total pulse number of 2400 at one cycle.

ATE -> Low (Not use ATE)

VREF -> 3.3V (Connect to V3P3 directly) and sense resistors are 0.25 ohm (Remained as default volume on the evolution board ).

TOFF -> Low

TRQ 0/1 -> Low/Low (100%)

Hopefully I respond correctly for your questions,

Yohjiro,

Hi Yohjiro,

Thank you for your response.

Is it possible to capture current waveforms of both directions?

Please confirm the following:

M1 and M0 are set to logic 0 (full step mode)
What are DECAY1 and DECAY0?
What is the motor specifications (manufacturer, model, current rating, voltage rating, resistance, inductance)?

 Hi Rick,

I captured current wave-forms of both directions by using a current probe.

(Please confirm the attached file)

I checked signal states.

M1/M0 -> 0/0 (Full step)

DECAY1/0 -> 0/0

In any case, I tried ATE mode with maintain decay1/0 = 0/0, however, the situation was not changed.

 

Motor manufacture: Shinano Kenshi

  Model: SST43D1105

  You can see the specifications of the motor in the catalog of the another attached file.

 As it is described the motor's rated current is 1.4A. However, in this time, I use it as over current mode up to 2A

in order to boost the torque. I discussed over current mode operation with the engineer of the manufacture, and

they allowed me the operation.       

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By the way, I noticed the way to avoid malfunctioning of the motor.

I accelerate motor speed from 1000 pps to 3000 pps with acceleration-rate of 10000 pps/s. 

And I often encountered the malfunctions mentioned before.

Meanwhile if I decreased  acceleration-rate below 5000 pps/s, I never encountered the errors.

In my case, is the acceleration-rate really effective factor?

However, why I do not encounter the malfunctions when I do not change DIR direction?

In my design of the motor control, I prefer faster control of it to be shorter control time.

Yours,

Yohjiro,

Current probe observation.pdfSST43D1105.pdf

  

  

 

 

Hi Yohjiro,

Thank you for the current waveforms. The abnormal case is seen as the motor stalls and the back EMF collapses. The current can then reach the desired value.

Accelerating too quickly can cause this to occur.

May I suggest you ask the manufacturer about the acceleration rate? When the direction is changed there may be slight differences in the driver or motor construction that causes one direction to operate while the other direction stalls.

Hi Rick,

Thank you for your suggestion. Now I am asking the mater with the manufacturer .
Actually, I confirmed normal output signals from the driver when I disconnect the cables between the driver and the motor. Now I know that the problem is derived from the matter of the motor. I really appreciate your corporation on this matter and understanding my terrible English.

Lastly, I would like to ask you a couple of questions bellow.
1) Honestly, I am not able to understand the benefit of the using the ATE.
Is using the function beneficial in my operation case?
2) In order to suppress raising temperature on the driver, Is changing torque % effective way?
e.x. Set the torque to 100% while rotating the motor and lowers the torque to 50% or 25% wile stopping the
motor.

Sincerely yours,

ADTEC Plasma Technology Co. Ltd.
Yohjiro Kawai,