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TMS320F28379D: REGARDING Eqep MODULE IN THE MCU

ashutosh bhatt
Expert 1490 points
Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

Sir, 

This is Regarding the given Example code for the processor, I tried to use the eQEP module for speed measurement for 3Phase ACI motor(around 5KW).

The issue is this when I measure the speed with externally powered the motor, the speed measurement is very good. But when I started my Inverter with DC link of around 500 volts, the speed measurement goes wrong even very wrong. 

I tried to find out the issue and I found that when the inverter starts the qep signal picking high-frequency noise and this not is very easily picked up by the processor's eqep module and make the speed measurement wrong. 

So Is there is any solution which eliminates the noise. I want to measure Eqep real pulse only. 

Ashutosh

  • 0
    TI__Genius 15935 points
    Hi Ashutosh,

    Can you tell us which example code are you using?

    Best regards,
    Chen
  • 0 in reply to Chen Jiang ti
    Expert 1490 points

    C:\ti\c2000\C2000Ware_1_00_01_00\device_support\f2837xd\examples\cpu1\eqep_pos_speed\cpu01

  • 0 in reply to ashutosh bhatt
    TI__Mastermind 24095 points
    Hi Ashutosh,

    If you are observing noise on the QEP inputs, it can potentially corrupt the speed measurement.
    In order to make the eqep inputs more immune to noise you can turn on the input qualification of GPIOs.
    Please refer to the GPIO section of the TRM and further look for Input Qualification.

    "Select input qualification
    If the pin will be used as an input, specify the required input qualification, if any. The input qualification
    sampling period is selected in the GPyCTRL registers, while the type of qualification is selected in the
    GPyQSEL1 and GPyQSEL2 registers. By default, all qualification is synchronous with a sampling
    period equal to PLLSYSCLK. For an explanation of input qualification, see section Section 7.4."

    -Bharathi