Hi Pauluzs > On 20 Oct 2017, at 12:43, Pauluzs <[email protected]> wrote: > > This might be the way small con/pro-sumer goods are going to take, > Although having an industrial background, i don't see this trend going to > change soon. > Can't imagene larger motor with integrated drives etc. just not practical, > modulair and to costly.
Apart from that, introducing an external microprocessor will introduce communication with the hal. And when looking at canopen devices (with integrated encoder and closed loop into the device) one runs into bandwidth problems pretty fast with the default 1ms servo rate. I'm not convinced the ti processor with PRU will disappear soon. Look at the recent Octavio system chips. > All that aside and back to the beaglebone, still wondering if the pru's would > be capable of generating the (s)pwm for 18 pins at a reasonable rate. > lets say at least 20khz which is above audible at my age and seems to be > about the switching frequency used in several drives. Getting back to your original question: I'm afraid I'm not savvy enough to answer the pwm part. Maybe the beagleboard forum can answer this better. About the blcd component: Iirc the commutation is calculated in the hal component. So depending on the update rate and the processor you probably are limited in speed. But in all honestly I have not tried a blcd setup (yet). Hope this helps a bit. > > >> On Tuesday, October 17, 2017 at 10:14:17 PM UTC+2, Pauluzs wrote: >> Hi all, >> >> Currently i'm looking into driving 3 phase (steppers) motors on 3 axis with >> encoders the Beaglebone. >> This because i got several 3 phase pm bldc motors, some small 48v ac servo's >> and 2 large 220v ac servo's i would like to drive. >> While looking into the 3 phase bldc steppers the idea came it would >> potentially also being able to support ac servo's. >> >> After making a pinmux layout it would be possible to connect: >> 3 encoders eqep A/B/INDEX (or 3 hall sensors on the same inputs) >> 6 PRU 0 signals U/V/W phase hi and low >> 12 PRU 1 signals U/V/W phase hi and low >> >> This would mean each phase could have a hi and low pru capable pin driving >> it. >> Using discrete power components it would be cheap and simple to build a >> drive. >> Or power driver IC such as the International Rectifier [IRAMS] (according to >> http://wiki.linuxcnc.org/cgi-bin/wiki.pl?BLDC) >> >> There are some questions i run into: >> Can the beaglebone/machinekit even keep up with this amount of pwm pins? >> Should i use the pru stepgen code? (stepgen does not seem to support 3 >> phase) >> Should i use the pru pwm code? >> Use the bldc component with standard writes? >> Or use the bldc component with pru_pwm? >> >> Usefull thoughts or comments are most welcome, >> >> Thanks, >> >> Paul >> > > -- > website: http://www.machinekit.io blog: http://blog.machinekit.io github: > https://github.com/machinekit > --- > You received this message because you are subscribed to the Google Groups > "Machinekit" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > Visit this group at https://groups.google.com/group/machinekit. > For more options, visit https://groups.google.com/d/optout. -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
