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POWER BRICK AC Quadrature Encoder output
#1
I like to do the following with a Power Brick AC unit:
Take the signal from a sinusoidal encoder, modify it a little using a compensation table and then generate a quadrature encoder output.
This quadrature encoder signal will then be send to another motion controller.

How can this be done with the Power Brick AC unit?
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#2
(03-27-2018, 01:23 PM)AJZ Wrote: I like to do the following with a Power Brick AC unit:
Take the signal from a sinusoidal encoder, modify it a little using a compensation table and then generate a quadrature encoder output.
This quadrature encoder signal will then be send to another motion controller.

How can this be done with the Power Brick AC unit?

Hi,

You could process the SIN/COS encoder through the ECT and then create a virtual axis that follows the position of the processed SIN/COS encoder. Reference the section(s) below in the Power PMAC SRM which describes how-to configure the PFM Output to generate quadrature outputs (simulated quad encoder):

Gate3[i].Chan[j].PfmFormat Description: IC channel PFM output format control
Range: 0 .. 1
Units: Boolean
Default: 0
Gate3[i].Chan[j].PfmFormat determines the signal output format of the PFM circuit on Phase D of the IC’s channel. It is only active if Gate3[i].Chan[j].OutputMode is set to a value of 8 or greater to specify PFM output on Phase D.
If Gate3[i].Chan[j].PfmFormat is set to the default value of 0, the output is in pulse-anddirection mode. This mode is useful for control of traditional stepper drives and the excitation of MLDT sensors.
If Gate3[i].Chan[j].PfmFormat is set to 1, the output is in quadrature mode. This mode is useful for creating a synthesized incremental encoder signal.
(In some pre-release versions of the Power PMAC firmware, this element was named Gate3[i].Chan[j].PfmOutFormat.)
Gate3[i].Chan[j].PfmFormat constitutes bit 19 of the full-word element Gate3[i].Chan[j].OutCtrl. It is write-protected, so it cannot be changed without first writing the proper key value into Gate3[i].WpKey (which happens automatically in the script environment if the proper key value is in Sys.WpKey)


To change direction of the quadrature output:
Gate3[i].Chan[j].PfmDirPol

-Chris
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#3
Thank you for your reply, Chris.

How do I connect the virtual motor position to the synthesized incremental encoder output signal?
And how fast will the output signals update?

Adrian
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#4
Follow the instructions in the Power PMAC Users Manual to set up a motor to command an external pulse-and-direction stepper drive. The only difference is that you will use the PfmFormat variable Chris mentions to convert the output format from P&D to quadrature.

This virtual motor will use the sinusoidal encoder value as its master to follow the sinusoidal encoder position processed through the encoder conversion table. Yu will need to set up Motor[x].pMasterEnc, Motor[x].MasterCtrl, and Motor[x].MasterPosSf for the virtual motor.
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