Hi,
I can get the motors to run smooth when I jog, but when running the demo in mach 3 they sound terrible.
First lets dispel a myth, Mach3 Demo and Licensed Mach3 run identically. The only limitation that need concern you is that Demo
is limited to 500 lines of Gcode at a time. The kernel frequency of Mach3 Demo is limited to 25Hz, but this need not concern you,
unless, as previously explained, you choose to set a too higher microstepping regime; if you keep to 8 microsteps per full step
or below the limited kernel speed will have no effect.
The fact that the motors run smoothly when jogging tells us that the steppers and drivers are good, it also tells us that the BoB
and Machs parallel port can produce the required high quality pulse stream. The fact that the same steppers/drivers/BoB run poorly
when processing code suggests to me that Mach's parallel port is running poorly when the Gcode interpreter is commanding
motion.
My guess is that when the Gcode interpreter is running it introduces a heavy demand on the PC's interrupt system which in
turn causes excessive jitter within Mach's parallel port driver, itself an interrupt driven timer.
Proving that this is so is not straight forward.
Would you please post a screen shot of DriverTest.exe. Its not conclusive but is still a fair indication as to the health or
otherwise of the parallel port driver. Note that some PC's seem to do a good job with a parallel port and another machine,
possibly with much higher specification, does poorly. There is no way to tell short of installing Mach and trying it.
Have you considered an external motion controller such as an Ethernet SmoothStepper or a UC300? One of the
advantages that an external motion controller offers (vs the parallel port) is very high quality, high speed pulse
streams WITHOUT being dependent on PC hardware. Should you consider this option you should budget somewhere
in the $150-$300 range, if you buy cheap Chinese rubbish you'll have even less luck with it than the parallel port!!!
Craig