Tandem Axis with one Home/Limit switch
03 Sep 2020 23:54 #180605
by palador
Tandem Axis with one Home/Limit switch was created by palador
Hi! I'm using linuxcnc 2.7 for a while now and switched to 2.8-pre3 now. As I did last time, I used pncconf to setup my machine. Before switching, I made a backup of my old config and even screenshoted all 2.7 pncconf settings.
My machine is a 3 axis router with two steppers for the y-axis. The y-axis has one switch for homing and limit.
I'm using a mesa card.
With AXIS 2.8, I have some issues which confuse me a lot:
- 4 joints are shown instead of 3 axis. Can I disable that, since both y-joints must always be synchronous, anyway?
- homing doesn't work for the y-axis: as soon it hits the limit switch, one joint stops, but the second seems try to move further.
I see the y-joint2 coordinate in axis moving while the other joint stands still and is marked as homed. idk if this happens also to my machine, because it's stiff and can stall the motor.
I don't want to do all that auto square stuff. I just want to have two steppers connected to my mesa card and both to behave like one.
My machine is a 3 axis router with two steppers for the y-axis. The y-axis has one switch for homing and limit.
I'm using a mesa card.
With AXIS 2.8, I have some issues which confuse me a lot:
- 4 joints are shown instead of 3 axis. Can I disable that, since both y-joints must always be synchronous, anyway?
- homing doesn't work for the y-axis: as soon it hits the limit switch, one joint stops, but the second seems try to move further.
I see the y-joint2 coordinate in axis moving while the other joint stands still and is marked as homed. idk if this happens also to my machine, because it's stiff and can stall the motor.
I don't want to do all that auto square stuff. I just want to have two steppers connected to my mesa card and both to behave like one.
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04 Sep 2020 01:30 #180611
by phillc54
Replied by phillc54 on topic Tandem Axis with one Home/Limit switch
To hide the joints, try changing this ini file line:to:
In your hal file you have:each of these need an individual signal name.
you also have:but no y2 connections to any 7i76 inputs.
You should really have separate switches for each joint. If you want to try to use a combined switch for the Y axis then make the signal names for Y1 and Y2 the same like:
KINEMATICS = trivkins coordinates=XYYZ kinstype=IDENTITYKINEMATICS = trivkins coordinates=XYYZIn your hal file you have:
net both-home-y => joint.1.home-sw-in
net both-home-y => joint.1.neg-lim-sw-in
net both-home-y => joint.1.pos-lim-sw-inyou also have:
net y2-home-sw => joint.2.home-sw-in
net y2-neg-limit => joint.2.neg-lim-sw-in
net y2-pos-limit => joint.2.pos-lim-sw-inYou should really have separate switches for each joint. If you want to try to use a combined switch for the Y axis then make the signal names for Y1 and Y2 the same like:
net both-home-y => joint.1.home-sw-in
net both-min-limit-y => joint.1.neg-lim-sw-in
net both-max-limit-y => joint.1.pos-lim-sw-in
net both-home-y => joint.2.home-sw-in
net both-min-limit-y => joint.2.neg-lim-sw-in
net both-max-limit-y => joint.2.pos-lim-sw-inPlease Log in or Create an account to join the conversation.
04 Sep 2020 11:03 #180655
by palador
Replied by palador on topic Tandem Axis with one Home/Limit switch
Thanks a lot for you help, now it's all working.
I did everything as you suggested. For other newcomers I want to make one point a bit clearer:
has to be replaced with
So with both modifications in ini and hal you just replace lines and don't add or remove some.
I did everything as you suggested. For other newcomers I want to make one point a bit clearer:
net y2-home-sw => joint.2.home-sw-in
net y2-neg-limit => joint.2.neg-lim-sw-in
net y2-pos-limit => joint.2.pos-lim-sw-innet both-home-y => joint.2.home-sw-in
net both-min-limit-y => joint.2.neg-lim-sw-in
net both-max-limit-y => joint.2.pos-lim-sw-inSo with both modifications in ini and hal you just replace lines and don't add or remove some.
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