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Feed Hold in arcs
« on: December 14, 2012, 01:57:33 AM »
Hello,

I just recently got my mill some what up and running. I'm in the process of running some parts to test how everything is work. I have run in to a problem with feed holding while in an arc move. If I feed hold in an arc move and try to cycle start to continue the cut the cutter ends up moves in random directions. Mostly it seems to takes off in the + Z and -Y and -X directions. I thought that this may only be related to doing a helix move but it also does it on a basic 2D profile arc.

When this happens I get and "Radius to end of arc differs from radius to start" error. From what I have read this error seems to happen the most if you Mach and your cam software are not post arcs the same way. INC vc ABS. I have checked and have both systems setup as INC I also have my code output a G91.1.

This is with the latest lock-down (.66) version of Mach3. My system consist of ESS using the latest lock-down plugin (10hd2), PMDX-126, PMDX-107. This system is on my knee mill.

I have spent some time browsing the forums and the yahoo group and have seen some post about this problem but none of them have a solution and they are quite old.

What I find some what odd is I also have Mach on my router and I can feed hold and continue any time I want on it with no problems. On difference is the router is a PP system and not and ESS system.

Any suggests other then trying to run my knee mill as a PP system with out the ESS?

Thanks
    -Wes
« Last Edit: December 14, 2012, 02:04:17 AM by Snipes44 »
-Wes

Offline BR549

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Re: Feed Hold in arcs
« Reply #1 on: December 14, 2012, 11:41:33 AM »
Nothing so far is as dependable as the old PP. WIth motion controllers THEY have to make their end work as the PP does, not many have mastered it.

(;-) TP
Re: Feed Hold in arcs
« Reply #2 on: December 16, 2012, 02:48:48 AM »
Ok so I have tried a number of different versions of Mach with the same result. Even tried the .57 version which in the change log says that this issue was fixed. But it still does it with that version. I get the "Radius to end of arc differs from radius to start on line number" error message. I did fresh installs of mach, including deleting the mach folder and going through and reconfiguring all my ports/pins/motors.

Yes I have checked the arc center mode and both my post/code and Mach are set for inc mode.

Any ideas?

Thanks
    -Wes
-Wes

Offline ger21

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Re: Feed Hold in arcs
« Reply #3 on: December 16, 2012, 07:41:34 AM »
Quote
I get the "Radius to end of arc differs from radius to start on line number" error message

it would appear that when you restart from a pause, the arc center is calculated incorrectly. Probably relative to the feedhold position rather than the actual start of the arc.

As Terry said, the Smoothstepper plugin handles the feedhold, not Mach3. So it's unlikely that changing Mach3 versions would help. You need to contact Greg at Warp9 and have him fix the plugin, or narrow down where the fault actually lies..


Gerry

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Offline BR549

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Re: Feed Hold in arcs
« Reply #4 on: December 16, 2012, 01:02:01 PM »
No the arc problem IS a mach3 problem. I outlined a proceedure to make it work in one of his other posts on the subject.

(;-) TP

Offline BR549

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Re: Feed Hold in arcs
« Reply #5 on: December 16, 2012, 01:39:01 PM »
But in testing I never got the error message that he does, so something else is in play there. Gerry you are correct on the main problem on feedhold mach3 looses it reference point back to the start of the arc and tries to pickup mid arc and that is not going to happen with the current mach3.

The way around it is to Feedhold /stop RFH.  Works every time here testing the worst case senario HELIXs.

One question one should ask is why am I having to stop mid program all the time ???

(;-) TP
« Last Edit: December 16, 2012, 01:41:26 PM by BR549 »

Offline BR549

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Re: Feed Hold in arcs
« Reply #6 on: December 16, 2012, 01:45:44 PM »
ALL that yapping and I AM in the wrong post .

SHEESH, (;-) TP