AnsweredAssumed Answered

Real breakpoints with ADC and interesting phenomenon

Question asked by Zheng Liang on Aug 8, 2017
Latest reply on Aug 9, 2017 by edison

I'm using STM32F103CB to convert the analog outputs from three polar hall sensors arranged circularly, a magnetic actuator rotates in the center, but I get the voltage value with strange breakpoints, and these happened with a interesting phenomenon which happens with a phase at voltage value of 2048  and I can't explain why, maybe someone had faced this problem, please help and tell me how to solve this.

 

Problem phenomenon: the value from ADC channel will have a breakpoint when it or other ADC channels in ADC channel group at voltage 2048, here are the screenprint with brief:

  1. Single channel reading:
  2. Tow phases with 60° space:
  3. Tow phases with 120° space:

  4. Three phases with 60° space:

 

 

What I tried to solve this:

  1. disable DMA
  2. change the hall sensor output voltage amplitude
  3. replaced three F103 chips
  4. changed the rank of ADC channel times
  5. disable ADC2 and only use ADC1
  6. disable ADC1 and only use ADC2
  7. dual ADC mode
  8. add more delay in converted interruption

but nothing changed

 

If you have some suggestions, please let me know

 

Thanks,

Zheng

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