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Author Topic: Mach4 - Is it possible to stop the jog faster?  (Read 293 times)

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Mach4 - Is it possible to stop the jog faster?
« on: April 27, 2023, 12:33:56 PM »
What I mean is, the table keeps moving for a moment after I let go of the key. I don't expect an instant stop, but things were good in Mach3 and this is very jarring. It seems to matter how long I keep the key pressed down. If I just tap it, it doesn't take as long to stop. I played around in the UC100 settings panel, but I can't get anything to change. I am running at 100kHz and 50ms buffer. I thought it may be the buffer, but that's as low as it can get, so it doesn't matter.

Stepping works correctly as far as I can tell.

I copied over the motor settings from Mach3 to Mach4 (I have a Taig that came with a profile for the motors for Mach3).

Re: Mach4 - Is it possible to stop the jog faster?
« Reply #1 on: April 30, 2023, 05:50:32 PM »
this post should be on the Mach4 General Discussion board, no doubt Tweakie will shift it in due course.

That is a common 'problem' that you describe, I put the 'problem' in quotations because it is not actually a problem or fault with Mach at all....its doing exactly
what its supposed to do.

There are two jogging modes in Mach (3 OR 4), incremental or velocity.

The most common is incremental mode, and what you have described is what you are doing. In incremental mode the machine will advance 0.1mm or whatever 'incremental distance'
you have programmed into Mach with each button press, or wheel spin if using an MPG. The problem arise when the 'increments' stack up faster than the machine can go. Those extra 'increments'
are stored up....so after you release the button or stop spinning the MPG they will still be executed. That is called 'after-run' and that is doing exactly what you wanted. You issued
say 1000 'increments' and now it goes ahead and does them.

This results because in incremental mode with keyboard jogging when you hold a button down Windows interprets that as repeated button presses and thus by holding the button
the 'increments' get stacked up.

I used to have my max increment set to 1mm per increment. I suffered greatly from the problem you describe, I'd stop spinning the MPG (holding the button) and yet the machine would carry on until it had
consumed all those incremental moves I'd dialled up. This is essentially because the incremental distance is accumulating faster than the machine can consume them. I have reduced the max
increment to 0.1mm and now I can get the increments to stack up if I spin the MPG (hold the button) as fast as I can but mostly it never happens.

May I suggest that you try velocity mode. There the machine will advance at the programmed jog rate while you hold the button down, but stop the moment you release it.
If you are rapid jogging back and forth it is a good way to go. If you want to touch off to a part the incremental moves with a small increment is the safest and most accurate way.

'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
Re: Mach4 - Is it possible to stop the jog faster?
« Reply #2 on: May 01, 2023, 01:26:44 PM »
Thanks for the reply! That's exactly what I needed.   ;D

Offline kf2qd

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Re: Mach4 - Is it possible to stop the jog faster?
« Reply #3 on: June 03, 2023, 07:16:11 PM »
What are your axis accelerations set to? if you acceleration number is low, it will take a while to stop from high speed when releasing the jog button. As the Acceleration is turned set higher the movement will start and stop faster. If you turn the acceleration to high you will lose steps because the motors will not be able to keep up. Acceleration to low is better than to high, but closer to what your machine is really capable of is much better.