• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 82 subscribers
  • Views 480 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LAUNCHXL-F28069M: Improper Freq Read at eCAP1 (GPIO24) when measuring freq of HALL Sensor Position Feedback signal from the motor.

Sharat Yadav
Expert 1015 points
Part Number: LAUNCHXL-F28069M
Other Parts Discussed in Thread: CONTROLSUITE

I have just started working on the implementation of motor control, any advice/support is will be very useful to me.

I have written a code for SPWM to run the motor in open loop and controlling it via Scalar Control.

I have configure ePWM4 A/B at 500Hz and Configured eCAP1 (GPIO24 - J6 55) as capture pin. 

I am able to achieve the Scalar V/F control of the motor Properly and I am also able to capture the 500 Hz from the ePWM4 at eCAP1.

I am able to see the HALL sensor feedback output at the DSO, but when I am trying to capture the Hall feedback frequency and hence Speed, its showing some Random value at the capture.

The wave form of the Hall feedback is attached, To me the reason for failing to read properly is Noise in the Hall feedback waveform, which is leading to false capture of rising and falling edge,

I would like to have Solution/Suggestion about how to tackle this Issue.

  • 0
    TI__Guru** 115500 points
    You might have a look at the eCAP example code in controlSUITE that should help you to resolve the question. And you might enable the GPIO input qualification function and add an RC filter on the input signal to suppress the noise.

    www.ti.com/.../controlsuite

    C:\ti\controlSUITE\device_support\f2806x\v151\F2806x_examples_ccsv5
  • 0 in reply to Yanming Luo
    Expert 1015 points

    Dear Yanming Luo,

    I have gone through these examples and I am also able to use eCAP modules and have tested all the 4 examples as described in the Technical Reference Manual.

    I have tested my code to Capture edges and hence frequency and duty ratio for a range of freq varying from 1Hz to 20kHz.

    The Problem is: I am not able to capture the HALL signals from the motor on GPIO24 eCAP1,  the motor is run by ePWM1-3 A/B with scalar control using SPWM.