Tool Length Offset

ZX-Sinclair
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27 Aug 2015 19:13 - 27 Aug 2015 23:19 #61836 by ZX-Sinclair

Tool Length Offset was created by ZX-Sinclair

Hello, i want to use my plasma cutter with a torch height controller with a digital Z-up and down signal.
Is it possible to do a continuous probe with an adjustment of the z-axis during jogging in the X/Y direction?
With G43... it is not possible because they drop or lift the Z-axis only with a new Z value.
A continuous Z-adjustment during one long cut seems to be impossible?

or...

is it possible to lift the Z-axis with a simple (up) signal on one pin and to drop on another?

Last edit: 27 Aug 2015 23:19 by ZX-Sinclair.

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Rick G
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28 Aug 2015 18:01 #61858 by Rick G

Replied by Rick G on topic Tool Length Offset

Have you looked here...
linuxcnc.org/docs/html/man/man9/thcud.9.html
linuxcnc.org/docs/html/man/man9/thc.9.html

Rick G

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BigJohnT
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28 Aug 2015 18:31 #61861 by BigJohnT

Replied by BigJohnT on topic Tool Length Offset

G43 is not generally used with a plasma torch.

I don't know what you mean by a continuous probe while jogging this makes no sense. You can't probe while jogging.

Most plasma machines with a floating head work like this:
Do a G38 probe down in Z until the probe input changes.
Move up to the position where the torch is just touching then set G92 Z offset.
Move up to pierce height.
Start the torch and after pierce delay if any move to cut height.
Cut the part out with the THC feeding either up/down or voltage to a component that hijacks the Z axis with an offset to maintain tip voltage.

I wish I knew what you wanted to do so we could help you but it is obvious that your native language is not English and your translations leave us confused and you frustrated.

JT

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ZX-Sinclair
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28 Aug 2015 21:03 #61866 by ZX-Sinclair

Replied by ZX-Sinclair on topic Tool Length Offset

@Rick G
I translated all the docs about THCUD but there is no explanation how to "hijack" the Z axis.

@BigJohnT
Yes i have translate a lot....
My problem is to:
"Cut the part out with the THC up/down signal to a component that hijacks the Z axis"

It seems that it is not possible with gmoccapy-plasma without being a programming expert.
Now i'm playing around with axis, but i don't find an example that works with an up/down signal.

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BigJohnT
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29 Aug 2015 05:23 #61873 by BigJohnT

Replied by BigJohnT on topic Tool Length Offset

ZX-Sinclair wrote:
@Rick G
I translated all the docs about THCUD but there is no explanation how to "hijack" the Z axis.

@BigJohnT
Yes i have translate a lot....
My problem is to:
"Cut the part out with the THC up/down signal to a component that hijacks the Z axis"

It seems that it is not possible with gmoccapy-plasma without being a programming expert.
Now i'm playing around with axis, but i don't find an example that works with an up/down signal.

The "hijacking" is done inside the thcud component.

Is the Z axis a stepper drive or a step and direction drive?

All the connections are in the man page for the thcud but they might be a tiny bit confusing the way it ended up being formatted.

Physical Connections
paraport.0.pin-12-in <= THC controller Plasma Up
paraport.0.pin-13-in <= THC controller Plasma Down
parport.0.pin-15-in <= Plasma Torch Arc Ok Signal
parport.0.pin-16-out => Plasma Torch Start Arc Contacts

HAL Plasma Connections
thc.torch-up <= paraport.0.pin-12-in
thc.torch-down <= paraport.0.pin-13-in
motion.spindle-on => parport.0.pin-16-out (start the arc)
thc.arc-ok <= motion.digital-in-00 <= parport.0.pin-15-in (arc ok signal)

HAL Motion Connections
thc.requested-vel <= motion.requested-vel
thc.current-vel <= motion.current-vel

Of course you need to make proper hal line and use the parallel port pins that you have set up.

net signal-name pin-name pin-name
Example
net torch-up-input thc.torch-up <= paraport.0.pin-12-in

Pyvcp Connections In the xml file you need something like:

<checkbutton>
<text>"THC Enable"</text>
<halpin>"thc-enable"</halpin>
</checkbutton>

Connect the Pyvcp pins in the postgui.hal file like this:

net thc-enable thcud.enable <= pyvcp.thc-enable

JT

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ZX-Sinclair
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31 Aug 2015 13:57 - 31 Aug 2015 14:24 #61931 by ZX-Sinclair

Replied by ZX-Sinclair on topic Tool Length Offset

I use step and dir stepper.

My looks like that:

net thc.arc-ok  	motion.digital-in-02 <= parport.0.pin-12-in-not
net thc.touch  		motion.probe-input   <= parport.0.pin-13-in-not

net thc.requested-vel <= motion.requested-vel
net thc.current-vel <= motion.current-vel

net torch-up thcud.torch-up <= parport.0.pin-15-in-not
net torch-down thcud.torch-down <= parport.0.pin-10-in-not
net thc.requested-vel <= motion.requested-vel
net thc.current-vel <= motion.current-vel

#net torch-up-input thcud.torch-up <= parport.0.pin-13-in-not

If i remove the # i get: .hal:68: Pin 'thcud.torch-up' was already linked to signal 'torch-up'
So i have problems with "proper" hal lines :-(

During cutting i can see in the HAL the torch-up and torch-down signals,
but the Z is static.

Do i need the Pyvcp Connections for the function?

I have this in my xml:

<checkbutton>
<text>"THC Enable"</text>
<halpin>"thc-enable"</halpin> </checkbutton> <spinbox>

If i activate that via postgui:
net thc-enable thcud.enable <= pyvcp.thc-enable

i got "pyvcp.thc-enable does not exist"

Last edit: 31 Aug 2015 14:24 by ZX-Sinclair.

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BigJohnT
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31 Aug 2015 19:23 #61937 by BigJohnT

Replied by BigJohnT on topic Tool Length Offset

I assume you did not add your xml file to the ini as described here:

www.linuxcnc.org/docs/2.7/html/gui/pyvcp...#sec:pyvcp-with-axis

And you can not have more than one source connected to a signal in hal. See the diagram here:

www.linuxcnc.org/docs/2.7/html/hal/basic-hal.html#_net

JT

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ZX-Sinclair
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01 Sep 2015 12:55 #61980 by ZX-Sinclair

Replied by ZX-Sinclair on topic Tool Length Offset

My ini calls:
PYVCP = custompanel.xml

The postgui line:
net thc-enable thcud.enable <= pyvcp.thc-enable

In the custom.xml is:
<checkbutton>
<text>"THC Enable"</text>
<halpin>"thc-enable"</halpin> </checkbutton> <spinbox>

The error is:
pyvcp.thc-enable does not exist

also
thcud.enable does not exist
thc.enable does not exist

It is possible that there are double connections because i read a lot of different tutorials, but there is no global document (only man pages for programmers) and everyone is using it in a different way :-(

I uncomment the wrong lines and at the moment it works, but still without THC.

For me it is confusing why sometimes thc is used, sometimes thcud and how and why i have to connect the torch-up and down signals (that works) with the "hijacking" elements in thcud or linuxcnc or...?

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cncbasher
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01 Sep 2015 17:02 - 02 Sep 2015 02:19 #61984 by cncbasher

Replied by cncbasher on topic Tool Length Offset

as mentioned before post your current config as an archive
the problem you have is your mixing different versions of THC control , and not matching to the THC you are using
all this will do is cause confusion .

i am looking into this for you .

see attached parport pins , can you please edit to show your current connections ,
if their is any your not sure of let me know .
i have made a simplified hal file from the original example , so you can test once i have changed the parallel port pins to suit your breakout conections
once we have it working in axis , then we can look at gmocappy

attach your current file archive will help too

Last edit: 02 Sep 2015 02:19 by cncbasher. Reason: update

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ZX-Sinclair
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03 Sep 2015 01:54 - 03 Sep 2015 01:56 #62069 by ZX-Sinclair

Replied by ZX-Sinclair on topic Tool Length Offset

Ok. i installed a new axis and adjusted it...

Here is the hal:

loadrt thcud

net thcud.ok  		motion.digital-in-02 <= parport.0.pin-12-in-not
net thcud.touch  	motion.probe-input   <= parport.0.pin-13-in-not

net torch-up thcud.torch-up <= parport.0.pin-15-in-not
net torch-down thcud.torch-down <= parport.0.pin-10-in-not
#net thcud.requested-vel <= motion.requested-vel
#net thcud.current-vel <= motion.current-vel


net estop-out => parport.0.pin-01-out
net xdir => parport.0.pin-02-out
net xstep => parport.0.pin-03-out
setp parport.0.pin-03-out-reset 1
net ydir => parport.0.pin-04-out
net ystep => parport.0.pin-05-out
setp parport.0.pin-05-out-reset 1
net zdir => parport.0.pin-06-out
net zstep => parport.0.pin-07-out
setp parport.0.pin-07-out-reset 1
net adir => parport.0.pin-08-out
net astep => parport.0.pin-09-out
setp parport.0.pin-09-out-reset 1
net coolant-flood => parport.0.pin-14-out
net charge-pump => parport.0.pin-16-out
net estop-ext <= parport.0.pin-11-in

setp stepgen.2.position-scale [AXIS_2]SCALE
setp stepgen.2.steplen 1
setp stepgen.2.stepspace 0
setp stepgen.2.dirhold 35000
setp stepgen.2.dirsetup 35000
setp stepgen.2.maxaccel [AXIS_2]STEPGEN_MAXACCEL
net zpos-cmd axis.2.motor-pos-cmd => stepgen.2.position-cmd
net zpos-fb stepgen.2.position-fb => axis.2.motor-pos-fb
net zstep <= stepgen.2.step
net zdir <= stepgen.2.dir
net zenable axis.2.amp-enable-out => stepgen.2.enable
net home-z => axis.2.home-sw-in

In the HalConfiguration i can watch pins during cutting:
- torch-up
- torch-down
- touch
- ok
This are the four hardware pins from the THC electronic module.

The signal thcud "arc-ok" doesn't work...
Also all other values for Z-positioning.

Last edit: 03 Sep 2015 01:56 by ZX-Sinclair.

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Tool Length Offset

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