help with Y axis not working at slow rates

[n00b]

Hi,
I have a gekko G540 with EMC2 setup. I'm running dual X axis on a XYZ setup, with pins for the second X axis mapped to X and direction inverted.

The problem I have is that the Y axis will not move at slow rates. It does fine jogging at higher rates, but if I put the velocity at 0.1 in/min, it doesn't move in stepconf. It also doesn't move most of the time when running through G code.

Any ideas? I've already tried increasing jitter

[chester88]

Just a shot in the dark - i would check electrical noise or whether the parport has enough power to run all the axis. Is there a break-out board between the g540 and computer?
Is it a mobo parport or a PCI add on parport?

[chester88]

If you disconnect the two x axis will Y work properly?

[n00b]

It's a motherboard parallel port. I will disconnect X and see if Y works.

I thought it might be a noise problem as well, and moved the Gekko box around. All the cables between the G540 and the steppers are shielded (I believe) - purchased from cncrouterparts.com (9 pin connectors).

[n00b]

disconnecting the 2 X motors makes no difference.

Y won't move on the stepconf test at .1 in/sec... it works fine at .6 in/sec or higher.

[chester88]

next to try :
can you easily physically rewire the parport to move the Y axis to another set of pins?
or may be you can switch the pins in software for y and z to see if z is screwed up.
What we are trying to do is figure out if its hardware or software and exactly what part of the hardware.

Has this ever worked correctly?

[n00b]

Originally Posted by chester88 next to try : can you easily physically rewire the parport to move the Y axis to another set of pins? or may be you can switch the pins in software for y and z to see if z is screwed up. What we are trying to do is figure out if its hardware or software and exactly what part of the hardware. Has this ever worked correctly?

Hi, followed your recommendation by swapping Y and Z, and changing the pin mapping in stepconf. Everything seems to work now, which is great, but now I wonder what the problem could be.

And, this is a new machine - just finished assembly yesterday.

[chester88]

glad you got it fixed.
Sometimes that happens you take it apart find nothing wrong put it back together and it works!
annoying but as long as it works.
Probably a bad connection did it.

Chris

[n00b]

Thanks for your help.

I guess tonight I'll hook it up the "right" way and see if the problem returns - if so, I'll just leave Y and Z swapped and leave it alone.

[n00b]

well, I guess I lied... tried a different gcode file with more Z axis movement and today Z wouldn't move with slow rate (Z used to be Y) Switched things around, and problem moved to Y again.

This only happens at very slow jog speeds.

Any idea why?

[chester88]

sounds like a hardware problem. Do you have a PCI add on parport you can try or another computer? Is the parport wired directly to the g540?

[n00b]

I can try it, but I think I may have fried something on the G540.
I noticed Y does work when the unit is first plugged in (Even when moving slow)
Tried adjusting the trim on the Y - motion got choppy and G540 went into fault. Have not been able to prevent it from doing that since, no matter what I do with the trim pot. As soon as I plug in Y, it goes into fault.

X,Z and A still seem to work fine. Contacting Gecko