Unit101 Posted July 16, 2015 Share Posted July 16, 2015 How to reverse the direction sense of a PWM controlled motor on Power Brick. Here we assume the motor is typical 3 phase brushless with Quadrature encoder and using Halls for phasing. After successfully running setup: - you can power up - phase - home - jog motor ok - be sure you have the phasing setup ok first Now we want the motor direction sense to be opposite of what it is now: - E.G. now the motor turns CW with a Jog+ command we want it to go CCW Below the needed parameters to change: Gate3.Chan[j].EncCtrl: invert sense, so if now 7 make this 3 Motor[x].PhaseOffset: negate, so if now 683 make this -683 Motor[x].PwmSf: negate, so if now 15237 make this -15237 Motor[x].AbsPhasePosOffset: 2048 - Current value, so if now 613, make this 1435 Motor[x].AbsPhasePosSf: negate, so if now 170.6667 make this -170.6667 Now save, reset - phase the motor ($) and it the direction sense will reversed. Link to comment Share on other sites More sharing options...
bradp Posted July 21, 2015 Share Posted July 21, 2015 A lot of people are using serial encoders and cannot easily invert the counting sense. Could you add a procedure for this case. Link to comment Share on other sites More sharing options...
Unit101 Posted July 22, 2015 Author Share Posted July 22, 2015 Swapping Direction when Feedback is a Serial Encoder ? -I don't know how to do this with ALL the different types of serial encoders. -I have not yet tested the below ideas but based on Turbo Brick testing it should work fine as setup below. What I have found is that some allow you to swap the direction sense with wiring. For example the Sick-Stegmann SSI encoder has a wire to Pin which can be connected to GND to reverse the counting sense of the feedback. -If the Serial encoder does not allow you to invert its direction sense then I believe the best way to handle this is simply by swapping 2 motor leads UVW then doing the PWM setup based on this new direction. -If the Serial Encoder allows you to invert its counting sense then the parameters can be used to change this. Disregard the Gate3.Chan[j].EncCtrl parameter since it does not apply to a serial encoder and instead swap the direction sense at the encoder itself (such as with SSI type encoder). -Next you would adjust these parameters to reverse the command sense to motor. Motor[x].PhaseOffset: negate, so if now 683 make this -683 Motor[x].PwmSf: negate, so if now 15237 make this -15237 -For power on phasing use same parameters: -this may not apply to all serial encoder power on phasing Motor[x].AbsPhasePosOffset: 2048 - Current value, so if now 613, make this 1435 Motor[x].AbsPhasePosSf: negate, so if now 170.6667 make this -170.6667 If you do some testing and find different results or a better way, please post it here. Link to comment Share on other sites More sharing options...
Recommended Posts