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Original question:

PGA411Q1EVM: How to reflect register setting on PGA411Q1EVM ?

PGA411Q1EVM: How to select output(delta phi) ?

Kevin Wat
Prodigy 110 points

Part Number: PGA411Q1EVM

Hi,

PGA411-Q1

Sorry for bother you. According to datasheet, formula (14) and (15) show same output(delta phi:degree). then, I was confused. how to select delta phi output formula from (14) or (15). or this delta output means "Electrical Angle","Psychical Angle" ?

Best,
Kevin

  • 0
    TI__Mastermind 23810 points
    These are for two different types of output. Equation 14 is for the quadrature encoder output (figure 35), but equation 15 is for the commutation encoder output (figure 36).

    The two types work quite differently.

    Quadrature encoder output: OUTZ toggles at every zero crossing. OUTA/OUTB will toggle to cover every bit of resolution; however, they will need to be counted from the last OUTZ pulse to determine an absolute angle. This is a common output type.

    Commutation encoder output: Between the six signals, an absolute angle will be identified; however, the resolution with NPLE = 1 will only be 30 degrees. To increase the resolution, NPLE can be increased so that the full cycle will take place in 0 to 180 degrees (for NPLE = 2) instead of 0 to 360 degrees. I haven't seen many people use this output type.
  • 0 in reply to Clancy Soehren
    Prodigy 110 points
    Hi Clancy,

    My goal is to figure out this RDC can be measured psychical absolute angle or not(It looks RDC can measure electric angle).

    My understanding is quadrature encoder and commutation encoder encoder output "Electrical Angle". Is it correct?

    Best,
    Kevin
  • 0 in reply to Kevin Wat
    TI__Mastermind 23810 points
    You are correct. The PGA411 RDC will always output the electrical angle, regardless of the interface used.