I've resurrected a nine year old project and am finally adding CNC to my G3616 mill. Way back I bought DC Servos, HP_UHU controllers, pulleys, belts, angular contact bearings but everything languished in a box after the pattern for the HP_UHU heatsink was a failure so I never got past getting the drive to work.
Well for now I've given up on the heatsink pattern but I have finished one of the HP_UHU drives along with 90V power supply and Over Voltage Clamp circuit. Initial tests on the motor and drive were done with my E-Leadscrew unit. Castings and machining for the mill installation motor mounts are coming along. Now I've got the latest install of MachineKit on a Beaglebone Black which has a Xylotex BBB_DB25/26 cape which is connected to a Probotix PBX-RF Isolated Breakout Board. I've done some editing on the Xylotex.ini file to match what will be the 4:1 pulley to the Y axis and run a few of the sample .nc files. Motion of the DC Servo is silky smooth. Sweet. I'm not sure I've achieved maximum step rate yet. I'll put the scope on it to day to see if I've missed something there. According to the MachineKit forums max step rate is 50kHz and with my ratios I won't need more than about 49KHz. But. And it's a pretty big but. I'm running MACH3 on my JGRO modeled CNC router with stepper motors. If was pretty easy to add some code for the touch off button to be able to zero the tool tip with MACH along with limit switch installation and testing. So MACH3 is easy and works. The learning curve isn't that steep. Enter the MachineKit LinuxCNC port and in some ways I feel like I've stepped back into the dark ages. Simple things like how do I see if a limit switch is closing or not. There doesn't seem to be a screen with hardware interface. Etc. I can see in the .ini file where I can set max override but not max jog speed. I'd like to be able to output max step rate and verify that everything else is working. So is MachineKit just an interesting exercise for the College or University level? To show CNC can be done with a 1GHz 32 bit ARM? That the real solution is LinuxCNC on a 1GHz PC (or faster) with an external controller that can be set up with the Stepping Configuration program? I've got a Tormach holder and Tormach Tooling so eventually I want to build a tool changer. Same with Power Drawbar control and eventually Spindle Speed with a VFD. Other than using the SPI port out the Beagle to run external hardware I realize the Beagle has major limitations there. And if I procure a PC to run the CNC why would I not just add on a Ethernet Smooth Stepper and Probotix BoB and run MACH3? In either case, at the moment, I have the Beagle, it's running MachineKit, and it appears to run and drive the motor. Some sort of pendant is going to be mandatory. Do I roll my own pendant or is there one out there that is preferential for Linux. I have a Homann Designs MC-01 ModIO controller that has been used as the basis for a pendant. Comments? Thanks John ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
