Hi Andy, > There's nothing here that suggests I can swap the signals like Andy > > suggested for PWM. > > http://linuxcnc.org/docs/2.7/html/man/man9/hostmot2.9.html#stepgen > > > I suspect not. I was thinking that 'table mode' might save the day, but > step/dir is rather different to any of the table modes. > > But you seem to be driving STMBL drives? So I am very confused about what > your aim is. >
Here's the story. A bit long. I have 3 STMBL drives with only one connected to the AC Servo inside the Harmonic Drive for my 4th Axis. The knee has a Gecko Driven Stepper motor. X and Y axis are currently run with 90V DC Servos controlled with HP_UHU drives. I did try to use the STMBL for the DC Servos but suppor,t past getting them turning, just wasn't there. I'd ask how to prevent the noise while the motor was sitting still and there would be no answer. That was with them sitting on the bench. I needed to convert step/dir to RS422 before I could try them on the mill hence my little conversion board project. So for now I have my 2 other STMBLs with two extra (spare) drive chips as backup. Finding a 2HP 3 phase spindle motor to which I could connect an encoder was becoming problematic so I started looked for alternative AC Servos. Then I found the Bergerda drives from China and although there have been some teething pains I poured a casting for the small 400W unit that matched torque and RPM specifications with my DC Servos. Mounted it on the X axis. Smaller, just as powerful, and the result is I'm tempted to get a second so I can have them on X and Y and maybe a slightly larger one on the knee. The Bergeda 1.8kW motor for the spindle works with high speed stepping and also 0-10V which is where I am with the PWM control problem right now. I have my hal file configured to put out stepping pulses from the MESA P1 port but in keeping with the idea of a simple MACH3 to LinuxCNC conversion project I want to be able to run it with PWM to 0-10V (open loop) speed control. I had ordered 5 of the PC boards but got 6. By the end of the weekend I'll have the spindle motor turning with LinuxCNC and MACH3 via the 0-10V PWM signal. MACH3 is so much easier to configure compared to LinuxCNC that for now I'll just keep the old .pin file and use DB-25 pin 14 for PWM output. I just want to see the motor turn via LinuxCNC control but I didn't want to rewire things. So I have to make up one more little StepDir2STMBL translator board to drive the Bergerda at 500kHz step pulses when I connect to P1 of the MESA. But that will also require a ribbon cable adaptor of some sort because the PMDX-126 doesn't bring out the second parallel port step/dir pins. Clearly I'm not that happy with that BoB either. The STMBL is a great drive for motors with odd voltages like harmonic drive. The Bergerda AC Servo drives use 220VAC in and that's converted to DC so they won't work with a 160VDC drive. Otherwise I'd probably sell the STMBLs. So to sum up, I may just spend the money on a couple more Bergerda drives and replace the stepper on the knee. I want to maintain step/dir for motion control. And there's part of me that's being tugged in the direction of an Ethernet Smooth Stepper and MACH3 on WIN-10 with all the issues I'm having with the MESA. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
