On Thu, 11 Jul 2013, andy pugh wrote: > Date: Thu, 11 Jul 2013 00:58:41 +0100 > From: andy pugh <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: Re: [Emc-users] Custom firmware for MESA and BLDC motors > > On 11 July 2013 00:43, Peter C. Wallace <[email protected]> wrote: > >> The only thing that might be nice is to have the ability to enable/disable >> this optimization. The reason is that on drives like the 8I20 we plan to add >> a >> velocity pin that will allow extrapolation of the commutation angle in the >> drive. > > Good call. > > Currently JK's change is applied to the rotor angle, and then the > phase angle is added. > It might be better to modify the phase angle, and let drives that > receive rotor-angle (which frankly, is a group of one, the 8i20, as > far as I am aware) get that in the raw form. > > Having said that, until the 8i20 grows this new feature, and until the > 8i20 users re-flash their 8i20s, then this change is an advantage to > them (us) too. Wiring up the velocity pin would have to be done in > concert with disabling the bldc lookahead, so if you have the pin, but > not the option, nothing breaks if you don't wire the pin. > > This is not the case if the 8i20 were to calculate velocity internally > (Err, why can't the 8i20 calculate velocity internally?)
It can but its something of a nuisance to guess where and where not to apply velocity extrapolation (you dont want it during magnetic alignment for example) We considered a hueristic where we dont do extrapolation unless the acceleration is within reasonable limits and angle deltas are high enough to warrant extrapolation (dont do it based on a few random angle settings) We may take a stab at this shortly > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > ------------------------------------------------------------------------------ > See everything from the browser to the database with AppDynamics > Get end-to-end visibility with application monitoring from AppDynamics > Isolate bottlenecks and diagnose root cause in seconds. > Start your free trial of AppDynamics Pro today! > http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
