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Author Topic: Intermittent Stepper Stalling  (Read 2467 times)

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Intermittent Stepper Stalling
« on: September 09, 2012, 04:27:22 PM »
Hi,

I have a problem with Mach3 or my machine. I have a intermittent stepper stalling problem.

I can jog the machine at 8.5 m/min, all axis’s moving at the same time with no problem. The stalling comes in when I run Gcode.

It is not always at the same place, time or the same axis. Normally it will only happen after about 25min of cutting, plus or minus a few min. After the first stall I ref.home  and try to resume with the cutting, but it will just keep on stalling. Not in the same place and not the same axis.
If I restart Mach then I can cut without stalling for plus minus 25 min, sometimes this will work, but not always, might get a stall sooner. 
The stalls only occur on the X,B or Y axis, never had a Z axis stall. 

The Machine:

X and B axis slaved together with 585 oz/in steppers each, direct drive on a 3m ball screw, 10mm lead. Separate home switches.
Y axis is a 260 oz/in stepper also direct drive on a 2m ball screw, 10mm lead.
Z axis is a 120 oz/in stepper with small ball screw and 5mm lead.
X, B and Y are driven by the same type and size drivers and are connected to a 48v, 10 amp supply. The drivers are set to 10 micro steps and the amps to 3.7 amp.
Z axis has its own 30v,3amp supply.
 Motor settings on X, B, and Y are set to 7m/min and acceleration to 1000 with 200 steps per/ mm. The step pulse is set to 10us and direction to 5us.
Mach is set to a 35KHz kernel speed.

Currently I’m cutting 17mm thick chipboard at 5m/min and 8mm deep per pass.

I include my xml.

Then there is another problem. All the motors stall on the M3 command. Even if I disable my BB relay in the output settings, it will still stall all the axis’s. If I press F5 when the machine is running all the axis’s stall. I have to disable the ‘use Spindle relay’ in the settings otherwise when the program calls a M3 command the machine stalls out. The relay works correctly, it starts the router but then the machine stalls. I have tried it without power to the router and the same thing happens, even with the wires disconnected to the BB relay it still stalls.
I will appreciate any advice, thanks.

Offline Hood

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Re: Intermittent Stepper Stalling
« Reply #1 on: September 10, 2012, 03:04:31 AM »
It sounds more like a hardware issue such as drives getting overheated.
You could try the kernel at 25KHz as that is all you require if  running the axis at the above numbers (200 x 7000/60=23.333)

I have tested the M3 here with your xml and dont get a problem so again think it may be hardware related but just in case, what is in your M3 macro?
Hood
Re: Intermittent Stepper Stalling
« Reply #2 on: September 14, 2012, 12:38:00 AM »
Hi Hood,

Thanks for the reply.

I have traced the problem back to my breakout board, I swapped it out with a different one and all is well.

I noticed that the stalling only occurred after I switched on the router, so it must have been some noise from the router. The higher I set the rpm of the router the sooner it happened.
All my cables are screened, motors and limit switches so not sure how and where the noise got to my breakout board.

I also measured some strange voltage spikes 15 to 25 volts from the ground of my breakout board to the machine ground.

The problem with the M3 command was the delay settings, my M3 macro is Do SpinCW(), but when the machine is jogging it first wants to stop for the delay time set in the Ports and Pins settings. If I set the delays to 0 seconds it all runs well.