2 motors for the same axis
29 Oct 2015 04:15 #64415
by Gloup
2 motors for the same axis was created by Gloup
Hello,
I have a short question before configure my new CNC 3-axis.
I have 2 motors for the axis X, and each motors have its own limit switch.
Of course, to move, the 2 motors must be synchronized.
At the moment my configuration with the parallel port is like that => X Y Z X(A)
I read lot of things on the forum and all subjects corresponds to previous version of LinuxCnc.
My question is, with current version of LinuxCnc, is there something simple to make this kinf of configuration ?
If not, could you confirm me that I have to use Kins ? using this way ?
Hope you can help me to start in the right way.
thanks
I have a short question before configure my new CNC 3-axis.
I have 2 motors for the axis X, and each motors have its own limit switch.
Of course, to move, the 2 motors must be synchronized.
At the moment my configuration with the parallel port is like that => X Y Z X(A)
I read lot of things on the forum and all subjects corresponds to previous version of LinuxCnc.
My question is, with current version of LinuxCnc, is there something simple to make this kinf of configuration ?
If not, could you confirm me that I have to use Kins ? using this way ?
Hope you can help me to start in the right way.
thanks
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29 Oct 2015 04:41 #64420
by LearningLinuxCNC
Replied by LearningLinuxCNC on topic 2 motors for the same axis
I think you want to use gantrykins. You can see some information about it
here.
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29 Oct 2015 14:56 #64427
by Gloup
Replied by Gloup on topic 2 motors for the same axis
Thank you. I will continue in this way to try to understand gantrykins
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29 Oct 2015 18:32 #64437
by LearningLinuxCNC
Replied by LearningLinuxCNC on topic 2 motors for the same axis
There is a sample configuration in the configuration picker that uses gantrykins. It is under "Sample Configurations - sim - axis - gantry" in the config picker tree. There is a .ini file called gantry.ini and a HAL file called gantrysim.ini in the linuxcnc\configs\sim.axis folder.
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29 Oct 2015 23:19 #64464
by andypugh
Replied by andypugh on topic 2 motors for the same axis
Note that in the Gantrykins demo (and any other system that uses non-trivial kinematics) you need to switch to "World Mode" after homing.
This can be done through the menu in Axis, or with the $ keyboard shortcut.
You will see that in Joint mode the GUI shows joints 0, 1, 2, 3 and in World mode it shows XYZ.
This makes a lot of sense for a robot, but is a bit weird for a gantry.
Other ways to do this include using the Joint-Axes branch of LinuxCNC (which is experimental, so you might need to compile it) and the "Gentrivkins" kinematics module which allows joint mapping like gantrykins but does not lead to the separate joint mode / world mode.
Alternatively you may well prefer to just route the step-dir signals in HAL from one axis to two drivers.
This can be done through the menu in Axis, or with the $ keyboard shortcut.
You will see that in Joint mode the GUI shows joints 0, 1, 2, 3 and in World mode it shows XYZ.
This makes a lot of sense for a robot, but is a bit weird for a gantry.
Other ways to do this include using the Joint-Axes branch of LinuxCNC (which is experimental, so you might need to compile it) and the "Gentrivkins" kinematics module which allows joint mapping like gantrykins but does not lead to the separate joint mode / world mode.
Alternatively you may well prefer to just route the step-dir signals in HAL from one axis to two drivers.
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30 Oct 2015 15:22 #64506
by Gloup
Replied by Gloup on topic 2 motors for the same axis
Thanks for these complementary information.
I will try to configure the machine this evening. Just to be sure that I have clearly understand.
With routing step-dir signal: it's seems to be the easy way. But As I undestand this is a non sense to have limit switch on both X axis. And if I have a jump of step on an axis, I will need to recalibrate manually the position of axis. Is it correct ?
In case of gantrykins. Do you know if a person has already do a script to switch automatically to "Word mode" after homing. Or maybe if it's possible to add on the PyVCP panel a message to "alert" or give the state of this mode ? Because I'm sure I will forget it each time !
I will try to configure the machine this evening. Just to be sure that I have clearly understand.
With routing step-dir signal: it's seems to be the easy way. But As I undestand this is a non sense to have limit switch on both X axis. And if I have a jump of step on an axis, I will need to recalibrate manually the position of axis. Is it correct ?
In case of gantrykins. Do you know if a person has already do a script to switch automatically to "Word mode" after homing. Or maybe if it's possible to add on the PyVCP panel a message to "alert" or give the state of this mode ? Because I'm sure I will forget it each time !
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30 Oct 2015 17:15 #64507
by andypugh
sourceforge.net/p/emc/mailman/emc-users/....com.au/#msg28307696
If you look under the message titles one of them has a patch file, and other messages say how to use it.
Alternatively I can imagine that a simple userspace HAL component could watch for all the axis.N.is-homed pins going to "true" and issue a command to enter world mode. That may already have been done too.
Replied by andypugh on topic 2 motors for the same axis
Yes, that is correct. The other side of this is that if you home the Joints separately then there is likely to be a moment when the two sides of the X axis are heading in different directions. Homing slaved axes (especially to encoder index) in a truly general manner is a puzzle that has defied easy solution so far.With routing step-dir signal: it's seems to be the easy way. But As I undestand this is a non sense to have limit switch on both X axis. And if I have a jump of step on an axis, I will need to recalibrate manually the position of axis. Is it correct ?
It has been done as a modification to the Axis GUI, but I don't know how well it works.In case of gantrykins. Do you know if a person has already do a script to switch automatically to "Word mode" after homing. Or maybe if it's possible to add on the PyVCP panel a message to "alert" or give the state of this mode ? Because I'm sure I will forget it each time !
sourceforge.net/p/emc/mailman/emc-users/....com.au/#msg28307696
If you look under the message titles one of them has a patch file, and other messages say how to use it.
Alternatively I can imagine that a simple userspace HAL component could watch for all the axis.N.is-homed pins going to "true" and issue a command to enter world mode. That may already have been done too.
The following user(s) said Thank You: Gloup
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30 Oct 2015 17:23 #64509
by Gloup
Replied by Gloup on topic 2 motors for the same axis
I will read all these things. Thank you
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11 Nov 2015 10:46 #65112
by Gloup
Replied by Gloup on topic 2 motors for the same axis
Hello,
I'm back to you because I'm always trying to work my machine without success.
Regarding the example, I modify my conf.ini. For me it seems ok. I can switch the 2 mode with $ and make the home position. But I have a joint error when I want to use in manual.
I haven't modify the hal file except for "loadrt gantrykins coordinates=XYZX" because I really don't understand what I have to do.
Could you help me again ?
I'm back to you because I'm always trying to work my machine without success.
Regarding the example, I modify my conf.ini. For me it seems ok. I can switch the 2 mode with $ and make the home position. But I have a joint error when I want to use in manual.
I haven't modify the hal file except for "loadrt gantrykins coordinates=XYZX" because I really don't understand what I have to do.
Could you help me again ?
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11 Nov 2015 12:01 #65119
by andypugh
Replied by andypugh on topic 2 motors for the same axis
[quote="Gloup" post=65112I have a joint error when I want to use in manual. [/quote]
What is the exact error message?
What is the exact error message?
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