Help required 2.8 slaved axis

I am trying to set up 2.8 with slaved axis on X.
Using Linux debian 4.9.0-3-rt-amd64 #1 SMP PREEMPT RT Debian 4.9.30-2+deb9u2 (2017-06-26) x86_64 GNU/Linux


I seem to have the axis slaving OK but no movement is seen on the axis gui although the dro's show that both X1 & X2 are trying to home together.

when I toggle the x ,y & Z the radio buttons follow that. But the tool does not move on the gui.

I have not yet physically connected any home switches yet. What am I missing ?

For both joints 0 and 1, you need to change this to
I'm pretty sure that you also have some superfluous settings under each axes that belongs in the joints section

Joint axes need to have a negative number and the number should be the same for all joints that are shared.

I'm not sure how it will go without home switches which are integral.

Please read the Homing configuration for 2.8 as its changed from earlier versions.
linuxcnc.org/docs/devel/html/config/ini-homing.html

Thanks Rod
I have changed the sequence to -1 for joint one and joint two.

I get the same result. Please be aware that when it starts to home both X1 & X2 axis dro's change values together (as if it is homing)
But this is not reflected on the axis screen view of the tool ie. it does not move.

Also I don't have any motors connected yet so just watching the dro's

I have read the homing man page.

I see this from the man page;-

With mixed positive and negative values, joints 1 and 2 synchronized
[JOINT_0]HOME_SEQUENCE = 0
[JOINT_1]HOME_SEQUENCE = -1
[JOINT_2]HOME_SEQUENCE = 1

I thought that both number had to be negative !!

I'm pretty sure that you also have some superfluous settings under each axes that belongs in the joints section

Was you referring to these:-
[AXIS_X]
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
MIN_LIMIT = -0.001
MAX_LIMIT = 1200.0

[JOINT_0]
TYPE = LINEAR
HOME = 0.0
MIN_LIMIT = -0.001
MAX_LIMIT = 1200.0
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0

If so this is how it appears in the docs and all the slave configs I have seen. I have commented then out in the joint sections and it appear to work ok.

So what is the correct place to insert them?

For the benefit of others the tool on the axis gui screen does not move while homing (at least on mine) but once homed the tool will then move with jogging.

I still don't understand this from the docs:-

With mixed positive and negative values, joints 1 and 2 synchronized
[JOINT_0]HOME_SEQUENCE = 0
[JOINT_1]HOME_SEQUENCE = -1
[JOINT_2]HOME_SEQUENCE = 1

I thought that both numbers had to be negative for slaving !!

Thanks for the help with this, it is certainly taxing my brain:woohoo:

Clive,

I remembered I had published a minimalist working example based on a 7i76e on this thread

forum.linuxcnc.org/47-hal-examples/34072...antry-example#106523

Sorry for not being more specific previously but I think you have got HOME_SEQUENCE repeated in the Axis sections. (its a joint setting)

Clive s wrote: I still don't understand this from the docs:-

With mixed positive and negative values, joints 1 and 2 synchronized
[JOINT_0]HOME_SEQUENCE = 0
[JOINT_1]HOME_SEQUENCE = -1
[JOINT_2]HOME_SEQUENCE = 1

I thought that both numbers had to be negative for slaving !!

Thanks for the help with this, it is certainly taxing my brain:woohoo:

From the Documents for Master

HOME_SEQUENCE = <n> - Used to define the "Home All" sequence. <n> must start at 0 or 1 or -1. Additional sequences may be specified with numbers increasing by 1 (in absolute value). Skipping of sequence numbers is not allowed. If a HOME_SEQUENCE is omitted, the joint will not be homed by the "Home All" function. More than one joint can be homed at the same time by specifying the same sequence number for more than one joint. A negative sequence number is used to defer the final move for all joints having that (negative or positive) sequence number. For additional info, see: HOME SEQUENCE

JT

rodw wrote: Clive,
Sorry for not being more specific previously but I think you have got HOME_SEQUENCE repeated in the Axis sections. (its a joint setting)

Rod I don't see the HOME_SEQUENCE repeated in my Axis sections. I admit tho I am a bit dyslexic

But I do see in yours:-
[AXIS_Y]
MAX_VELOCITY = 360
MAX_ACCELERATION = 1500

Repeated in the joint sections but with different numbers. This is very confusing to me as you have;:-
MAX_VELOCITY = 300
MAX_ACCELERATION = 1500

and the docs show both in both sections. Do you think this is correct if so what numbers is Lcnc looking at?

Clive

That may have been an oversight on my behalf. I think that the axis settings will override the joints, particularly where a joint axis is defined. Remember an axis with multiple joints may not always be a gantry. It could be staged or telescopic or some other config so joints may move at different speeds.

forum.linuxcnc.org/media/kunena/attachme...e12-7_2017-08-31.hal
forum.linuxcnc.org/media/kunena/attachme...e12-7_2017-08-31.ini
this is from my gantry machine maybe that can help you

Yannis wrote: forum.linuxcnc.org/media/kunena/attachme...e12-7_2017-08-31.hal
forum.linuxcnc.org/media/kunena/attachme...e12-7_2017-08-31.ini
this is from my gantry machine maybe that can help you

Thank you. I do have a mock up working now. But I see a lot of difference in the layout of various ini files.
like:
Some have the [AXIS] section above the [JOINT] section and others like yours have them the other way round. Does it matter?

I see with conflicting MAX_VELOCITY entries
[AXIS_Y]
MAX_VELOCITY = 360
MAX_ACCELERATION = 1500

Repeated in the joint sections but with different numbers. This is very confusing to me, which take preference?
[JOINT 1]
MAX_VELOCITY = 300
MAX_ACCELERATION = 1500

Mine seems to work if I comment out the above just from the Joint section !!