• State
  • Locked Locked
  • Replies 6 replies
  • Subscribers 83 subscribers
  • Views 194 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.

TMS320F28379D: TMS320F28379D

Ben Qin
Intellectual 2690 points
Part Number: TMS320F28379D


Hi Team,

There's an issue from the customer need your help:

I plan to use the TMS320F28379D development board for digital control, and use the differential sampling inside the DSP to sample the AC voltage. Now I have a problem that the positive half-cycle and negative half-cycle sampling calibration curves of the AC are inconsistent. How to deal with this?

Could you help check this case?

Thanks & Regards,

Ben

  • 0
    TI__Mastermind 30185 points

    Hello Ben,

    Can you have the customer provide some data or a diagram of what they mean by positive/negative half-cycle sampling calibration curves? I'm not sure if they mean the trim values, or what these 'curves' inconsistent with.

    Best regards,

    Omer Amir

  • 0 in reply to Omer Amir
    TI__Intellectual 2690 points

    Hi Omer,

    in the first picture, the left is output voltage analog, the right is output voltage digital.

    Best Regards,

    Ben

  • 0 in reply to Ben Qin
    TI__Mastermind 30185 points

    Hello Ben,

    Can you please ask the customer to translate all the names in these graphs? Also, what are the x and y axis of both plots in the second image?

    What sort of calibration is being done here, is it calibration for the gain error? Has the customer already checked their data with the F2837xD datasheet that TI provides to confirm that the ADC is not meeting the specification (with the proper setup for measurement)?

    Best regards,

    Omer Amir

  • 0 in reply to Omer Amir
    TI__Intellectual 2690 points

    Hi Omer,

    The development board is used, the ADC sampling peripheral should have been configured, 16-bit differential sampling is used, the sampling window time register is configured as 15, and the frequency of the ADC sampling clock is divided by 4. The data obtained so far is calibrated based on the DC voltage, respectively. Observe the corresponding digital quantity in the sampling window for different values, and then perform linear fitting. I don’t know if this method is reasonable.

    Best Regards,

    Ben

  • 0 in reply to Ben Qin
    TI__Mastermind 30185 points

    Hello Ben,

    Omer Amir said:

    Can you please ask the customer to translate all the names in these graphs? Also, what are the x and y axis of both plots in the second image?

    What sort of calibration is being done here, is it calibration for the gain error?

    I need you to answer these questions first before I can proceed. I have no frame of reference where the numbers in the table/plots are supposed to be since it's not in English.

    Ben Qin said:
    Observe the corresponding digital quantity in the sampling window for different values, and then perform linear fitting. I don’t know if this method is reasonable.

    So the customer is plotting something and trying to verify that it's a linear fit, but what they're expecting is both plots to be relatively identical?

    Best regards,

    Omer Amir

  • 0 in reply to Omer Amir
    TI__Intellectual 2690 points

    Hi Omer,

     in this picture, the top is Input Voltage Sampling Calibration, the left is Output voltage analog, the right is output voltage digital.

    the x and y axis are output voltage analog and output voltage digital, the Chinese doesn't matter.

    Omer Amir said:
    So the customer is plotting something and trying to verify that it's a linear fit, but what they're expecting is both plots to be relatively identical?

    I'll check with customer.

    Best Regards,

    Ben