Dynomotion

Group: DynoMotion Message: 11535 From: lmp582002 Date: 5/16/2015
Subject: Configure SnapAMP
Attachments :

Tom,


I have been spending time in the Hallcomutate.c example program. I am used to setting up the KStep and have a few questions.


  1. Does this program replace the INIT program, or does it run in another thread?
  2. I dont see how the motor is commutated? See attached image.
  3. I am trying to understand all that needs to be done besides clamping the voltage, setting current limits, and adding hall sensor inputs.
  4. Can I use the step response screen when using hall sensors?
Thanks,

Scott
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Group: DynoMotion Message: 11536 From: Tom Kerekes Date: 5/16/2015
Subject: Re: Configure SnapAMP [1 Attachment]
Hi Scott,

Regarding:

#1 - You shouldn't need another thread.  Normally you would add this loop at the end of your INIT Program.

#2/3 - The function that distributes the output (A) to the 3 coils at phase angle F is:

        Write3PH(ch, A, F);  // Drive motor at phase angle 

F is not in units of degrees or radians, rather it is in fractions of a cycle (ie 0.5 -> 180degrees).

Do you understand this?  Do you understand that if you energize the coils in some constant manner the motor will tend to seek a spot where there is zero torque (like a stepper motor).  If there were any torque the motor would accelerate and not hold still.  Maximum torque would be 1/4 cycle away.

I find it too difficult to think everything through rigorously.  If you think you can go ahead.  I would just wire up the motor phases randomly.  Also wire up the Halls randomly.  Then rotate the motor very slowly like a stepper by energizing the coils and record the Hall sequence.  Then put that sequence into the table.  The Table is used in a way where a combination of Hall sensors maps to a rotor angle,

You could use the Auto Phase Find program to rotate the motor slowly like a stepper.

#4 Certainly. 

HTH
Regards
TK