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Author Topic: Stop, Feedhold, E-Stop  (Read 3763 times)

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Stop, Feedhold, E-Stop
« on: August 26, 2010, 12:34:41 PM »
For maintaining stepper to control software accuracy and consistency of position what is the best way to stop a program in mid run?  I have always used e-stop.  When my machine was running slower it was fine, but now that I get much faster rapids and even cut faster some times its a pretty hard stop. 

It seems like when I use feedhold or just stop I lose position.  I suppose it could be related to the fact that I have Mach set to run with high priority and it may take a couple instructions before it picks up the keyboard scan code, but I am not sure.  Seems like that would be an issue with E-stop too then. 

Offline Hood

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Re: Stop, Feedhold, E-Stop
« Reply #1 on: August 26, 2010, 01:23:07 PM »
Feedhold then once motion is stopped you can press Stop if you wish.
Feedhold will stop the motion in a controlled manner and you can either press Start to carry on, or press Stop to clear the buffer.
If you press Stop first then it halts motion immediately and the likely hood of you losing position is great, especially as you have found with a faster axis.
Hood
Re: Stop, Feedhold, E-Stop
« Reply #2 on: August 26, 2010, 01:37:48 PM »
I'll run some tests with a scratch engraver at max speed to test and see what happens, but I'm pretty sure feed hold lost position also. 

Offline Hood

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Re: Stop, Feedhold, E-Stop
« Reply #3 on: August 26, 2010, 01:46:53 PM »
Feedhold should not lose position, only way I can think of is if you pressed feedhold then pressed Stop before the motion had halted.

Interested in your findings though.
Hood
Re: Stop, Feedhold, E-Stop
« Reply #4 on: August 26, 2010, 01:54:46 PM »
I figure it will be pretty easy to test.  Just set a block of aluminum on the mill and write a program to engrave a couple nested squares over and over  again.  Hit feedhold.  Wait for it to stop, then hit start. 

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Re: Stop, Feedhold, E-Stop
« Reply #5 on: August 26, 2010, 02:00:02 PM »
It might be best to miss out the Stop and just press Start. If you press Stop,  I am sure, it clears the buffer so possibly the Start will not go right. Not 100% sure though as I have never tried it. I either press feedhold then once I have done whatever I want press Start or press FeegHold then Stop and if I need to restart I use Run From Here.
Hood
« Last Edit: August 26, 2010, 02:06:02 PM by Hood »
Re: Stop, Feedhold, E-Stop
« Reply #6 on: August 26, 2010, 09:53:17 PM »
I prefer set next line over run from here.  Its easier to know what its supposed to do next.  I like to select a next line that is a G00 to a safe Z height.  

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Re: Stop, Feedhold, E-Stop
« Reply #7 on: August 27, 2010, 02:26:45 AM »
Each to their own but the procedure is the same I would think. So how did the test go?
Hood
Re: Stop, Feedhold, E-Stop
« Reply #8 on: August 27, 2010, 12:13:32 PM »
My day job interfers with my hobby.  Did an alarm control swap and reprogram yesterday to a system with more user capability for a client.  Today I finish fixing an alarm for a client that ripped out a bunch of doors without a lot of discrimination.  The weekend I will be installing a video system in a busy office building because it would be a pain to do it during the week.  Got home tired every day this week.  I still need to swap my Gecko Control back onto the machine now that I got it back from Geckodrive, and I need to finish the enclosure I started.  I wleded up the aluminum pan for it the one afternoon I didn't get home tired this week.  I know.  I know.  Its just excuses. 

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Re: Stop, Feedhold, E-Stop
« Reply #9 on: August 27, 2010, 02:12:52 PM »
Ha ha no probs, just thought you were testing it last night.
Hood