-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2/1/2013 5:19 PM, Gregory Perry wrote: >> I'm not really sure. >> >> In most setups, LinuxCNC is processing the gcode and running a >> servo motion loop, which requires feedback and good latency >> timing. I'm not sure if you could get LinuxCNC to run 'blind', >> where the Linux side code could run with some sort of artificial >> feedback and collect up a series of motion points that you could >> feed to something like the PRU for conversion into steps. > > Ah, I see. So LinuxCNC itself has a realtime requirement as it is > actually driving the servos. So I wonder how LinuxCNC handles > standalone hardware CNC controllers that have integrated MOSFETs > or boost drivers for PWM servo control then?
That would be at the motor driver level. LinuxCNC would control the motor driver by generating step/dir pulses, or by generating an analog output signal (typically +/- 10V). The motor driver would then drive the FETs (or whatever) to turn the motor. Note that "motor driver" in this sense can be something like a tiny Allegro single-chip stepper-motor driver, or a board (or cabinet) sized collection of electronics, depending on the size of the motor. There are configurations for LinuxCNC that generate PWM for things like 3-phase brushless motor control, but that's typically done with hardware assistance from something like one of the boards from Mesanet.com. >> I believe this is more like how Mach works, which is why it can >> run with things like USB motion controller boards (that have >> horrible latency issues if you're trying to read back real-time >> position). > > What is Mach? A competitor to LinuxCNC? It's a closed-source machine controller that runs on DOS. http://www.machsupport.com/ - -- Charles Steinkuehler char...@steinkuehler.net -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlENECsACgkQLywbqEHdNFwgqwCg1sNG7V8J2Gpv6DK+Mpvyw6d0 eU4AoI5agBUJ3H2opgN9Oe1QdvWX1p+D =O+DH -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_jan _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
