----- Original Message ----- From: "Andy Pugh" <a...@andypugh.fsnet.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Monday, April 26, 2010 3:56 AM Subject: Re: [Emc-users] Resolver to Quadrature Convertor
> On 26 April 2010 00:58, RogerN <re...@wildblue.net> wrote: > >> I see brushless servo amps on ebay for reasonable but I think most >> require >> hall signals. >> >> http://cgi.ebay.com/AMC-brushless-servo-amplifier-BE25A20E-/310165227459?cmd=ViewItem&pt=BI_Control_Systems_PLCs&hash=item483749c7c3 > > I could put the Resolver to Hall signal code up on the Wiki, but I a > lot less confident that it is "right". Specifically I am not sure > which of the zeros of the resolver is considered zero degrees and how > the Hall signals typically correspond to that angle. It also needs > adjusting for different numbers of motor poles. > > If you are happy to fiddle with the table that correlates Hall signals > to resolver angle then I can publish the Arduino code somewhere. It is > something that seems fairly risk-free to tinker with, as the > worst-case is that the motor just stalls and vibrates. > > -- > atp > > ------------------------------------------------------------------------------ We have a couple different types of setup at work. One we have to loosen the resolver coupler and align to the field, I'm guessing that it puts some holding torque on the field, perhaps rotating a few degrees to make sure it's locked in. The other type you run a setup routine on and it learns the angle and stores in the controller. Taking an educated guess, I would rotate the field like a stepper motor, watch for rotation of the resolver, then rotate the field the other direction monitoring for movement. If the motor isn't under load, perhaps the armature will align up the field good enough for hall signals. When I first got these motors, I wrote a PIC program that output 3 phase PWM SIN wave and ran it like a stepper motor mini-stepping. I made up a 32 byte lookup table and put SIN values (Integer (sin(angle)+1) X 127) so 0 represented -1, 255 represented 1, etc. This value would be output PWM to a Half H-bridge, not a good one but good enough to experiment with. I was only using maybe 20V to the motor, it ran slow but it ran pretty good. Anyway, I think some setup procedure could be implemented to have the amp move and hold the armature, then either learn the angle or align the resolver. Roger Neal ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
