> From: andy pugh [mailto:bodge...@gmail.com] > On Mon, 16 Dec 2019 at 23:42, John Dammeyer <jo...@autoartisans.com> > wrote: > > > For example. The board in the machine at the moment generates a Servo > Jitter of 33217 and Base Jitter of 131983. > > That's fairly terrible. > > Out of interest, how well does that machine work with Mach3? >
That's a good question so I just had to go down and try it since it's been a while since I did that sort of exercise of moving windows with photos around while the machine is moving an axis. WIN-XP, Onboard (slower) video, 1024x768 to LCD monitor, MACH3, 60kHz Parallel Port setting. Machine Y axis: 0.2" pitch lead screw. 4:1 pulley from DC Servo DC Servo max RPM 3000, Encoder 250 lines (1000 PPR) Therefore 4000 pulses to move 0.2" or 20,000 pulses to move 1". Target speed 120ipm or 2ips which is 40kHz stepping pulses. Machine X axis: 0.2" pitch lead screw. 3:1 pulley from DC Servo DC Servo max RPM 3000, Encoder 250 lines (1000 PPR) Therefore 3000 pulses to move 0.2" or 15,000 pulses to move 1". Target speed 180ipm or 3ips which is 45kHz stepping pulses. Doing other activities while moving at those high rates does not appear to make the system lose steps or stop or declare faults. Having said that, the reason I switched to a USB Smooth Stepper on my CNC Router with MACH3 was that on an older, probably single core PC, doing anything like resizing a window while the system was running would cause loss of motion control due to motor lockup. I suspect because a) the processor wasn't fast enough b) an interruption and then catch up in step pulses to a stepper motor results in rapid changes in motor speed control that the motor itself cannot handle since the step pulses translate directly into winding current. With the DC Servo run with the HP_UHU drive and Henrik Olsson's dsPIC upgrade processor module, the slight interruptions to periodic step pulses don't change the overall motion with respect to closed loop control monitoring the encoder so the DC Servo doesn't get confused. And moving 6 inches at 180 ipm (3ips) is really fast. Kind of scary in itself. A lot can happen in 2 seconds. So in summary, no issues with MACH3 and parallel port stepping. I'd still upgrade to an Ethernet Smooth Stepper simply to remove that parallel port issue. Especially since I'd rather run WIN-7 on that PC and not WIN-XP. But I haven't decided yet between LinuxCNC and MACH3. There are aspects of the MACH3 user interface I like way more than the LinuxCNC one. There are also parts of LinuxCNC I like more. John Dammeyer _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
