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Author Topic: Tool moving to random coordinates  (Read 2586 times)

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Tool moving to random coordinates
« on: April 15, 2016, 01:38:39 AM »
This is very odd, once gcode is loaded and the head starts to move it moves correctly. However first I noticed if I am just entering code into MIDI (eg g0 x20) sometimes it moves correctly and other times it moves over a much greater distance even though the DRO still displays as though it has moved correctly.

I then moved the head to the location I wanted and just zeroed knowing I had excess stock to make up for any differences and ran the gcode, everything seemed fine though the z axis was incorrect so I left everything the way it was and just altered the z coordinates before running the post processor again. I ran the gcode and the head moved about 20mm away on the Y coordinate and started running as if the stock was right below it but it obviously wasn't.

Another thing, I think this is only happening in the Y axis.

Please give any suggestions?
Re: Tool moving to random coordinates
« Reply #1 on: April 15, 2016, 05:45:15 AM »
An update, the x axis also moves a larger distance than I put in the gcode but only sometimes. If I repeat the same line over and over just with a - sometimes (so back and forth) the distance it moves changes. Not every time

Offline RICH

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Re: Tool moving to random coordinates
« Reply #2 on: April 15, 2016, 05:54:49 AM »
The controller, namely Mach, provides for proper axis movement based on current defined configuration and mode.
As a newbie suggest you study  to understand coordinate system, work offsets, etc as what seems odd is just correct for what
you have told the controller.

RICH
Re: Tool moving to random coordinates
« Reply #3 on: April 15, 2016, 05:59:25 AM »
Thanks for your help but if I tell mach3 the same code and it moves a different amount?

Offline Hood

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Re: Tool moving to random coordinates
« Reply #4 on: April 15, 2016, 10:08:01 AM »
It could be you have binding on an axis and with the motor tuning set to the max capabilities of your motors you are stalling.
Reduce the values in motor tuning (Vel and Accel ) for the offending axis and see if that helps.


Another thing it could be is your pulse from the parallel port is not very clean, have you run the driver test to see what it looks like?
That is assuming you are using the parallel port and not an external controller.
Hood
Re: Tool moving to random coordinates
« Reply #5 on: April 16, 2016, 12:22:22 AM »
Thanks, all the setup was with files the manufacturer sent me so that shouldnt be the case.

It uses a USB connection so should I still be checking everything is functioning fine with that?
Re: Tool moving to random coordinates
« Reply #6 on: April 16, 2016, 02:40:18 AM »
Its all good it was my understanding of the gcode and not being perceptive, I feel very silly. Because I wasnt looking at the DRO just the movement of the head I was expecting when I entered axis and distance to move back it would just move back to where it started but instead it was moving to whatever that coordinate was and not the entered distance if that makes sense.

Offline Davek0974

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Re: Tool moving to random coordinates
« Reply #7 on: April 16, 2016, 03:11:09 AM »
Sounds a bit like you were mixed relative and absolute moves - you tell it G0 X10 and it moves 10mm not to X10 itself??
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Tool moving to random coordinates
« Reply #8 on: April 16, 2016, 03:49:28 AM »
Thats what I thought but Im pretty sure it moved to that point. Im not in front now but pretty sure I double checked, is that possible? I'll check again. It totally explains what was happening if thats the case though

Offline Davek0974

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Re: Tool moving to random coordinates
« Reply #9 on: April 16, 2016, 07:08:41 AM »
One thing I learnt was that anything is possible :)

It will (usually) do exactly what you tell it, whether that is right or not is another matter ;)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives