Which mode is best for new setups?

I don't really know. Where would it be located? I am only aware of the KNEE and the leadscrew motion. As the leadscrew spins it pushes the knee up or pulls it down.

A lead screw driven knee? In that case it isn't too surprising the motor is struggling at low speeds. That is a lot of weight to move coupled with the fact that a leadscrew can have a lot of static friction, (especially when worn). Adding a counterbalance to carry the weight could help, but it may also bring to light a lot of backlash that is there already but masked by gravity. A ball screw conversion could also help.

OK let me rephrase ...there's a long screw down there but whether or not it's a ballscrew or leadscrew I can't say. So perhaps it's already a ballscrew because it' spins so freely on the way down that you can hit spots where the leaver keeps spinning by iteslf for 10 or 15 revolutions... Makes me laugh when it does that.

If this was a manual machine your converting, it won't be a ball screw.

It was a CNC machine, already had servos on X & Y and whatever was on Z was manual with a 1/2hp 3-phase motor to jog up and down as needed. -Basically a mercy switch for up/down. I can try to take a pic of the screw in close but I doubt even then we could tell if it's a leadscrew or a ballscrew as they look very similar in many cases. The nut riding on the screw is mostly hidden from view so that doesn't help much. In the manual they call it nut for knee elevating shaft and knee elevating screw. It doesn't matter much what it is; the fact of the matter is the setup works well and with a more powerful servo my Z should be fine. The backlash may be held in check by gravity, but that doesn't matter much to me either since I won't be turning gravity off anytime soon.

thadwald wrote:

Todd wrote:

Never understood why people would try to use such ultra fine micro stepping with a step motor. 50x micro steps sounds like utter nonsense to me. Especially when you consider what the real resolvable accuracy of a step motor actually is (maybe 4x for accuracy and 8x max for smoothing out the steps). I guess there could be the advantage that if the drive missed a dozen or so steps, it really might not make much difference in the real position of the motor, but...

I'm not sure why other people do it but I used this setting as an attempt to quiet down the noise and the associated "harmonic stall" (I just made that term up.. not sure what it's called or even if it's called something) at certain frequencies. My theory is that when the step frequency or its harmonics coincide with the mechanical resonance in the drive system, the drive becomes easier to stall. Increasing the microstepping count reduces the step noise and gives you more torque at that specific speed. I believe some of the nice stepper drivers can somehow avoid those frequencies ...

Also, some people may like the noise of a stepper system but I don't. At those microstepping frequencies, the motor noise becomes a faint squeal, as opposed to the the typical squawk. I figured that since it's an option, why not?

I've seen some stepper drives advertised as having a clean sine wave output. Ultra fine micro stepping is the next best thing, no?

Todd wrote:

I'm not sure but isn't the max resolution on those Clearpath motors only 6400 steps/rev (if you have the high res version, otherwise only 800),

This is correct.

Way late to the party on this one but the step drivers themselves are huge as far as noise both audible and smoothness. I'm a big fan of Stepperonline's digital step driver's. They're rebranded Leadshine drivers and the "digital" versions make a huge difference over what I guess is considered an analog driver. I swapped out a reasonable quality driver for one of these and the annoying stepper noise completely went away running both at 8x. I run a very high step rate with small geared steppers on one machine and a more typical step rate with a 5mm pitch coupled ballscrews on another and they're both pretty quiet. WIth the original drivers I was losing steps because I was doing like you mentioned, increasing the microstepping at the drives to try to quiet it down but you just lose alot of torque/ I use a DM320T, a DM556T and a DM860I on a couple different machines now..

andypugh wrote:

You could try motion.adaptive-feed. (though that needs a floating point variable)
Comnverting the bit to a number and passing it through a lowpass HAL component might have interesting effects here..

But you probably want halui.program-pause
linuxcnc.org/docs/2.7/html/man/man1/halui.1.html

OK Tried the program pause but I already have the setup to my gamepad.
net pgm-pause halui.program.pause
net pgm-pause input.0.btn-thumb2 #3

I'm trying to also tie this input pin to pgm-pause.
net Z_Fault <= hm2_7i43.0.gpio.032.in

I've tried all kinds of combinations and it doesn't want to let me do it. I think I'm missing something simple.