Quote Originally Posted by Davidh
Ok here is a thought.

my square G code has 14 lines all in.

my circle has est. 450 lines. Remember the circle will fit into the square so its periphery is even less.

At the same speed both files need executed in about the same time.

Could the trouble be that my computer( well overspec for mach3)/mach3 cannot execute the file at a fast enough rate and then the pulses get mushy, loose thier defination, whatever the term is?


Maybe it is time to start swapping motors/cards about to see if the trouble moves.

I would think has nothing to do with the number of lines in GCode. 450 lines isn't that much code. I've had mach run cuts with 100,000 lines of code without a hitch... I shit you not... Doubt it's "mushy pulses" either unless you're talking about some kind of pea related obstruction spread along your guides etc...... even on a an old 1.4 ghz duron mach software will output 46,000 pulse per sec. The default mach config of 25k pulses per sec is usually more than enough to run steppers.

To suggest Mach is losing pulses and machine is stalling on a cut of 40mm length doesn't really hold up. Mach reserves 6 axes worth of resources and you're only running 3 If Mach starts losing pulse then it usually does it overall.. effecting the speed of all axes. Axes are driven by exactly the same hardware all the time. If the hardware can run it fast in straight lines theres nothing to suggest it should run any differently on non-straight cuts. On a straight or non-straight cut the axis will reserve an identical # of pulses per sec, and mach software will prioritise maintaining a constant pulse rate. Mach doesn't know/care about type of motion.. just sends step + dir pulses at the required place and rate throughout the motion. dir is on off signal, step is on off signal.. absolutely no difference in straight vs non-straight.... in many ways the kite is the same as a circle to mach software.

Try swapping the X and Y axis output pin settings in Mach setup... see if the problem transfers... this will save you dismantling anything to start with. If the problem transfers then suspect your driver hardware, something in the step and dir connections from the parallel port to the drive or the Gcode itself It might also be something in the OS but I doubt it. If the problem does not transfer (which is actually what I think will happen) then it's time to suspect the motor settings, PSU or something intermittent in the power connections, loose power lead into a drive could produce this problem or loose connection from drive to motor... Could possibly be the motor spec or configuration... motor might be internally configured to run 2 active phases per step... which doubles current requirements... but again would think specs would have shown this.

On the basis of the info you've given.. the Y axis does not stall on straight line cuts at all. You don't suggest that it stalls when moving on it's own. It stalls in combined motion with other axes on non-straight cuts.. you say it stalls even on air cuts, which you didn't mention before and also why I suggested deflection as place to start... You also didn't mention some other important info...so I'll have to ask for it..

Have you made sure there's no feedrate adjustment in the Gcode for the circle ?
Is feed overide in use on the circle ?
Have you tried feed overide to see if it makes any difference ?
Does it stall\lose steps if you jog all 3 axes together or jogging 1 back and forth while jogging others ?
Does it stall immediately on the Y-axis.. or only above a certain speed ?
Is it a constant loss of steps.. or a single big stall ?
Are you sure the problem is restricted to a single axis ?
What OS are you running ?
Have you run the mach 3 optimisation ?.. i.e. switching off unused system processes.
Have you run the mach 3 pulse rate test on your machine ?
What IS your mach pulse rate on diagnostic page.. does this match set pulse rate ?
Have you run motor tuning ?
Are you sure your axis calculations (steps per unit) for mach 3 are correct and that settings are correctly applied
Are all motors\settings the same ?
Have you tried changing the origin position of the test paths along the Y axis.
What happens after the stall ? would it complete the motion\cut.. or stall again ?

The current limiting setup on your drives may also have a bearing on this.. i.e. is current limiting built in\adjustable.. if so how.. are settings correct for all motors.. that kind of thing..

hope this helps...