Remember Arc Lost position

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Re: Remember Arc Lost position

Postby Vmax549 » Tue Oct 25, 2016 5:40 pm

HIYA Keith , IF you stop teh Gcode and do NOTHING to disturb teh BUFFER then you can restart from teh actual lost arc point as it will simply pick up from where it left off. BUT if you disturb teh buffer then you must restart at teh beginning of teh Gcode block. SO how do you know if yo have distrubed teh buffer ?? GOOD QUESTION so that is why I simply restart teh way I do assuming teh Buffer has been disturbed

The UCCNC routine I use also takes advantage of teh Excellant RUN FROM HERE in UCCNC. THAT makes it easier as then UCCNC is responsible for getting teh torch back into position based on teh Line# you set .

Teh supporting macroloop simply waits for teh torch moving in dry run mode( THC off and M3 off) to CROSS teh refire point(+/-) and lights teh fire then reset THCon after a delay (if needed).

(;-) TP
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Re: Remember Arc Lost position

Postby Robertspark » Wed Oct 26, 2016 11:13 am

Vmax549 wrote:Teh supporting macroloop simply waits for teh torch moving in dry run mode( THC off and M3 off) to CROSS teh refire point(+/-) and lights teh fire then reset THCon after a delay (if needed).


The problem with this is the macropump or macroloop delay ... and also you need to refire with m10 ... but by the time the m10 is initiated (at 25hz macroloop) the torch may have gone past the refire position

Any macro examples ? Even from mach3?
I've seen yours Andrew, but that is a plugin one and I didn't think I saw how control would be handed back over to uccnc gcode run from here, next line
Rob
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Re: Remember Arc Lost position

Postby Vmax549 » Wed Oct 26, 2016 1:25 pm

hIYA Robert, So far it has NOT missed yet here (;-). I use the standard M3 to fire teh torch. There IS a trick to it I have not explained. I have used a version of it in both Mach3 and UCCNC. after I test it a bit more then I will release it.

All it is is a macroloop that watches for teh torch to get within a kerfs width of teh refire point and it fires teh torch. At that point teh torch is traveling at a known feedrate(reduced from normal ) so teh distance to refire is always known. After teh refire is completed teh macroloop goes back to sleep mode until it is needed again.

(;-) TP
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Re: Remember Arc Lost position

Postby beefy » Wed Oct 26, 2016 4:15 pm

Andrew,
thanks for the plugin code. I've been very busy (and knackered) the last couple of days so haven't had a chance to look into it but after a quick look I realised there's some code in there I don't understand yet. So I'll have to look further into that one.

Terry,
thanks for that info. So it does seem like there is room for a new feature if it's easy enough for Cncdrive to implement. Getting back to what I mentioned before, at present we need to start at the gcode block and if that was a two metre long arc and the flameout point was near the end of that arc, we have to wait a while for the dry run to get to the restart position. I see another POTENTIAL scenario with this where the touch off is done at the beginning of the gcode block and due to the long distance, unless the metal is perfectly flat/parallel to the XY axis the cut height may no longer be accurate at the flameout point.
So overall that's why I like the new feature idea, we could set a dry run restart distance PLUS a refire position BACK along the cut path from the flameout point. No need to go all the way to the start of a gcode block if the distance is quite large.

Rob,
good point about the macro loop delay but I see an easy fix. Increase the proximity distance based on the dry run feedrate, ensuring the travel could not PASS the proximity window distance within the loop delay time.

Keith.
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Re: Remember Arc Lost position

Postby Robertspark » Wed Oct 26, 2016 6:00 pm

Keith I had same thought about lost arc position and doing a touch off .... then I thought.... do you need to do a touch off? Given the torch should have been at the right cutting height when the flameout occurred.... then the torch is at the right height for an on the fly start....

Problem is... a 2m retract to start of line could be another issue.... unless you used that clever pcb plugin to correct for bed height (autoleveler).... and did a few touch offs
Rob
Einstein ― “If you can't explain it to a six year old, you don't understand it yourself”
...working my way through the 1000+ ways things don't work to find the one that does
UC400eth, UC300eth, UCCNC v1.2105, Neuron Lite
UCCNC v1.2105 Macro Manual
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Re: Remember Arc Lost position

Postby shad » Wed Oct 26, 2016 7:42 pm

beefy wrote:Andrew,
thanks for the plugin code. I've been very busy (and knackered) the last couple of days so haven't had a chance to look into it but after a quick look I realized there's some code in there I don't understand yet. So I'll have to look further into that one.

Hello Keith! The main thing - after then arc lost issue you can start from any point of the cutting path if you have exact XY position of the path (of course if you not disturb motion buffer and not open new gcode file). I am never use torch refire on the fly. Just move torch to the arclost position (by G0 command) - turn on THC - command M3. Torch rereference on the part (or skip reference and move down to the stored cutting height) then controller turn on cutter.... Also operator can skip pierce.
But if you want to refire on the fly, you have to move for example on 10 mm before arc lost position. I have been ask to Balazs about adding new future. Add two buttons - Trace Forward (now this is not problem via Start button), Trace Backward (like reverse run) for jogging along cut path. I think it's will be helpful and I guess is not only for this task. :)

Anybody tested new UCCNC version? I mean return on the ArcLost position after then ArcOK signal was lost? Just I can't to see this future in the Release list.
-- Andrew
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Re: Remember Arc Lost position

Postby Vmax549 » Thu Oct 27, 2016 2:36 am

Hi Andrew you should be able to test this in teh current version as per Balazs,

"So, this is already implemented in the current official release also. :) "

(;-) TP
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Re: Remember Arc Lost position

Postby Vmax549 » Thu Oct 27, 2016 3:54 am

oK I stopped long enough to test that function in teh new test version. I set up teh axis for a slow acceleration so I could see it stop and back up. Testing here when I remove the ArcOK signal teh axis stopped without deacceleration and it did not back up.

But being it stopped without acceleration the stop point would be the same as lost arc point and would not back up.

(;-) TP
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Re: Remember Arc Lost position

Postby shad » Thu Oct 27, 2016 5:32 am

Vmax549 wrote:But being it stopped without acceleration the stop point would be the same as lost arc point and would not back up.

Hello Terry! I think stopped without deceleration is not good. I will try to make any tests too.
Or may be this future can be turned on/off? :?
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Re: Remember Arc Lost position

Postby cncdrive » Thu Oct 27, 2016 8:29 am

The ArcOK lost situation is deccelerated and movement compensated back not with the Acceleration parameter acceleration,
but with the Compensation acceleration (Comp.accel) parameter.
The Comp accel parameter plays always in case something needs to be compensated, it is used for the backlash compensation also.
So, I think that you tested with changing the Acceleration parameter low leaving the comp.accel parameter high and this is why you did not notice the decceleration and the moving back, because it happened too fast.

Now I have just tested it and it works as I described, it deccelerates and moves back to the Arclost position.
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