Different MAX_VELOCITY on different Axes
19 May 2020 17:03 #168285
by kjames
Different MAX_VELOCITY on different Axes was created by kjames
Hi all,
I have an old Sieg-X3 rebranded mill that I converted to CNC years ago but I never managed to get it to work right. Fast forward to now and I now have garage space and funds to get it properly working.
It's running off a RPi4 with a TB6600 4-axis board. I have everything working, but all three axes have different maximum velocities before they start to lose steps. I've figured out the max safe velocity for each axis using Fxxx/G1 commands. I have put these in the MAX_VELOCITY settings in the .ini file for the three axes and joints.
My problem is that when I run a program generated from CamBam it uses a lot of G0 to move in between operations and these don't seem to honour the MAX_VELOCITY on each axis, instead they seem to honour the slider in the UI (AXIS). I kind of assumed G0 would go at the lower of MAX_VELOCITY or the UI slider, but that doesn't seem to be the case.
Am I configuring something wrong? Happy to provide any more info if I missed something out..
Thanks,
Kev.
I have an old Sieg-X3 rebranded mill that I converted to CNC years ago but I never managed to get it to work right. Fast forward to now and I now have garage space and funds to get it properly working.
It's running off a RPi4 with a TB6600 4-axis board. I have everything working, but all three axes have different maximum velocities before they start to lose steps. I've figured out the max safe velocity for each axis using Fxxx/G1 commands. I have put these in the MAX_VELOCITY settings in the .ini file for the three axes and joints.
My problem is that when I run a program generated from CamBam it uses a lot of G0 to move in between operations and these don't seem to honour the MAX_VELOCITY on each axis, instead they seem to honour the slider in the UI (AXIS). I kind of assumed G0 would go at the lower of MAX_VELOCITY or the UI slider, but that doesn't seem to be the case.
Am I configuring something wrong? Happy to provide any more info if I missed something out..
Thanks,
Kev.
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19 May 2020 23:59 #168320
by cmorley
Replied by cmorley on topic Different MAX_VELOCITY on different Axes
post your config files please
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20 May 2020 09:30 #168350
by kjames
Replied by kjames on topic Different MAX_VELOCITY on different Axes
Thanks! Please find attached
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20 May 2020 10:16 #168354
by Clive S
Replied by Clive S on topic Different MAX_VELOCITY on different Axes
What version of linuxcnc ?
MAX_VELOCITY = 2400.0 this seems very high if I am not mistaken this is in machine units per sec. So 144M/min
MAX_VELOCITY = 2400.0 this seems very high if I am not mistaken this is in machine units per sec. So 144M/min
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20 May 2020 10:19 #168355
by tommylight
Replied by tommylight on topic Different MAX_VELOCITY on different Axes
Can your machine do 144 meter per minute ?
The velocities in the ini file are in mm/s, and yours are all over the place, they should be:
in the display section and the traj section, can be a bit more than any individual axis, so moving two axis at the same time will still allow for each axis to reach MAX VELOCITY.
each axis/joint has two max velocity, one for axis and one for joint, they should be the same, although it will work even if they are not.
If your machine can do 2400mm/m, set them to 40mm/s, time 60 gives you 2.4m/m
The velocities in the ini file are in mm/s, and yours are all over the place, they should be:
in the display section and the traj section, can be a bit more than any individual axis, so moving two axis at the same time will still allow for each axis to reach MAX VELOCITY.
each axis/joint has two max velocity, one for axis and one for joint, they should be the same, although it will work even if they are not.
If your machine can do 2400mm/m, set them to 40mm/s, time 60 gives you 2.4m/m
The following user(s) said Thank You: kjames
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20 May 2020 10:27 #168360
by kjames
Replied by kjames on topic Different MAX_VELOCITY on different Axes
Thanks guys,
I think I may have got a bit mixed up with units. I was using F commands to keep upping the speed of each axis and then using G1 back and forth until I got missed steps, then backed off a bit. That's where I got the 2400 from..
It sounds like, from what you're saying, that the F speed is mm/min, and the MAX_VELOCITY is mm/sec. Is this correct? If so I can go change those numbers and hopefully everything will be good.
And I'm using version 2.9.0 pre 0
Thanks,
Kev.
I think I may have got a bit mixed up with units. I was using F commands to keep upping the speed of each axis and then using G1 back and forth until I got missed steps, then backed off a bit. That's where I got the 2400 from..
It sounds like, from what you're saying, that the F speed is mm/min, and the MAX_VELOCITY is mm/sec. Is this correct? If so I can go change those numbers and hopefully everything will be good.
And I'm using version 2.9.0 pre 0
Thanks,
Kev.
The following user(s) said Thank You: tommylight
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20 May 2020 10:42 #168364
by tommylight
Replied by tommylight on topic Different MAX_VELOCITY on different Axes
Yes and yes.It sounds like, from what you're saying, that the F speed is mm/min, and the MAX_VELOCITY is mm/sec. Is this correct? If so I can go change those numbers and hopefully everything will be good.
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