On Sat, 2008-09-20 at 12:18 +0100, [EMAIL PROTECTED] wrote: > I read with interest the recent thread on Spindle Speed in the hope it > would answer my question, but it didn't quite get there! > > I'm converting a Boxford 190VMC mill to use EMC. I have everything > basically working but I have been unable to figure out how to get > closed > loop control of the spindle speed. The spindle has a 50ppr encoder and > is driven by a variable speed drive that wants a 0-10V signal to span > the range up to 3500rpm. The voltage/speed relationship is quite > non-linear. > > I've hooked up a counter to give me a speed readout via pyvcp. At the > moment I'm driving the spindle open loop using a lookup table > implemented with the linear8 Hal component. > > But how would I implement closed loop speed control? Is there some > documentation I've missed, or can someone give me some pointers > please? > > Steve
Basically, you need to connect your spindle encoder to a HAL encoder input. Then in HAL, connect the encoder signals to the motion.spindle inputs, then motion.spindle outputs to a DAC (digital to analog converter). My lathe setup is like this: ... ### Connect spindle encoder ### # Set counts per revolution setp ppmc.0.encoder.03.scale [SPINDLE]INPUT_SCALE # report rev count to motion controller net spindle-pos motion.spindle-revs ppmc.0.encoder.03.position net spindle-index-enable motion.spindle-index-enable \ ppmc.0.encoder.03.index-enable (this and previous line are one line) #(See: http://www.linuxcnc.org/docview/html//man/man9/motion.9.html ) ### Connect spindle DAC ### # connect DAC's enable pin net SpindleDACen or2.0.out parport.0.pin-17-out # connect spindle DAC, set scale value to match spindle # RPM at +10 V on VFD (ex. 3000 rpm = 10 V * 300 rpm/V) setp ppmc.0.DAC8.00.scale [SPINDLE]DAC_SCALE net spindle-speed motion.spindle-speed-out ppmc.0.DAC8.00.value ... The complete config is here: http://www.wallacecompany.com/cnc_lathe/HNC/emc2/configs/ http://www.wallacecompany.com/cnc_lathe/HNC/ Of course, your setup will be different, but similar. This probably isn't enough information, but should get you started. Kirk ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
