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Messages - Pompey Dockyard

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1
General Mach Discussion / Re: Mach3 Z Axis drilling problem
« on: February 10, 2021, 06:53:33 PM »
Further reading:
Last night I watched two very good YT videos by Peter Passuello, who has the CNCnutz channel, in which he discusses constant velocity and its downfalls and ways around it.
I am now much the wiser and know why I had the problem. ::)

Cheers,
Davo.

2
General Mach Discussion / Re: Mach3 Z Axis drilling problem
« on: February 10, 2021, 05:04:31 AM »
Add line

N185 G61

and line

N2905 G64

and try it.

Thanks Graham, that fixed it.
I had a sneaking suspicion it was somehow tied up with constant velocity but it threw me when it worked OK in Single Block mode.
I assume Mach3 defaults to Exact Stop mode when in Single Block.
I've changed all my other drilling code to suit and all work fine now.

Cheers,
Davo.  ;D

3
General Mach Discussion / Mach3 Z Axis drilling problem
« on: February 09, 2021, 05:35:52 AM »
Hi All,
I have the latest version of Mach3 running on a Windows XP Pro PC.
I am using a Gecko G540 stepper controller, using the parallel port for my mini-mill.
I have some G-Code that I generated with VCarve Desktop for drilling holes - it looks fine to me but when I run it the Z axis doesn't drill down far enough - all the X and Y axes run fine.
As far as I can see the Z axis is -2.5mm short of where it should be for every hole (it doesn't stay there long enough to be sure of the DRO reading). However, the strange part is that if I run the code in Single Block mode the Z axis depth is always correct for each hole.
I have Windows XP Pro and same Mach3 running on my Mac under Parallels as a test bed and it does the same thing - even though there is no hardware connected, so it isn't the hardware, the only thing common is Mach3 and the G-Code.

I have attached one of my G-Code programs (they all have the same problem). Can anyone explain what's going on and give me a fix?

Many thanks,
Davo.

4
Are you trying use the spindle speed PID in Mach 3? If so turn it off and also delete any file in the Mach 3 folder/macro folder called 'linearity.dat'.

The SmoothStepper just generates pules, just like the parallel port. The only difference is that for a PWM spindle you can set the acceleration. The SmoothStepper and parallel port both adjust the output in a linear fashion, i.e. 50% speed output is a 50% duty cycle square wave output. Any non-linearity is the result of your speed controller/motor. The spindle speed PID Mach 3 is a function of the parallel port driver and it can help with non-linearity problems (sometimes it works OK and sometimes it does not). It does not work with an external device so if you have it turned on or have a linearity .dat file it will screw things up.
Jeff,
You said that you had turned off the PID in the file you posted for me, I haven't checked as I do not know anything about the PID!  ???
What is the PID and how do I turn it off if it is set? I know where the settings are for it (I think) but that's all, the numbers in the boxes and the check box combinations are a dark art as far as I am concerned.
What do the letters P I D stand for?
I will check for the presence of a linearity.dat file
As I have said before a few times, my speed controller works consistently and flawlessly under Parallel Port control (and still does if I try it) so there is no question of the speed controller or the motor being at fault.

Thanks,
Dave.

Well,
I didn't get any reply to my last post (above) about PID, or any further information from anyone, so here's the latest.
I checked for a linearity.dat file and deleted it. Tried all sorts of things after that but could not get to the point where the USB SS would control spindle speed any better than I had previously got it, in other words, not acceptable.
Interestingly, no matter what I did, a linearity.dat file always reappeared in the macro folder.
I hinted in an earlier post that I was thinking of buying a UC300 USB controller  (http://cncdrive.com/UC300.html) and maybe buying their software too (http://cncdrive.com/UCCNC.html).
I got so disillusioned with the SS I finally recently bought both cncdrive products. I'm still getting to know everything but so far it seems to beat the Mach3/SS combo hands down.
SS was a good concept and market leader but I'm afraid the seeming lack of support (and documentation) has let it down.

Dave.

5
I have had that runaway with a M3 startup also. I think I fixed it with changing the step/dir active high/low settings. I haven't been playing with that for awhile.
Bill, I'm not using step/dir for my spindle - it is PWM.

6
Are you trying use the spindle speed PID in Mach 3? If so turn it off and also delete any file in the Mach 3 folder/macro folder called 'linearity.dat'.

The SmoothStepper just generates pules, just like the parallel port. The only difference is that for a PWM spindle you can set the acceleration. The SmoothStepper and parallel port both adjust the output in a linear fashion, i.e. 50% speed output is a 50% duty cycle square wave output. Any non-linearity is the result of your speed controller/motor. The spindle speed PID Mach 3 is a function of the parallel port driver and it can help with non-linearity problems (sometimes it works OK and sometimes it does not). It does not work with an external device so if you have it turned on or have a linearity .dat file it will screw things up.
Jeff,
You said that you had turned off the PID in the file you posted for me, I haven't checked as I do not know anything about the PID!  ???
What is the PID and how do I turn it off if it is set? I know where the settings are for it (I think) but that's all, the numbers in the boxes and the check box combinations are a dark art as far as I am concerned.
What do the letters P I D stand for?
I will check for the presence of a linearity.dat file
As I have said before a few times, my speed controller works consistently and flawlessly under Parallel Port control (and still does if I try it) so there is no question of the speed controller or the motor being at fault.

Thanks,
Dave.

7
Hi Jeff, Sorry for the delay, have been busy with other things.
Thanks for looking at my XML and posting a revised version.
However the revised one did not work. Every time I issued an M3 command the spindle immediately ramped up to top speed, irrespective of what S command was issued.
Going into the Pulleys settings caused the spindle to ignore any M3 or M4 commands and refuse to rotate, the only way to get any spindle control back was to reboot the PC and the SS.
That happened every time I changed a pulley setting.

I tried a different PC, a different USB cable and anything else I could swap around or change but still the same result.

I went back to my previous XML (a later one to the one you looked at) that I had had some success with and it still worked OK, I then managed to tailor the pulley settings to get spindle speeds somewhere near to the entered S commands but I'm not happy at all with the way the SS handles spindle speeds - compared with the original PP connection it's a dog's breakfast.  :'(

Thanks for your help anyway.

Dave.

8
Did you ever get a response from Jeff about your configuration xml?

Unfortunately, no - for some reason it seems to have been ignored.  :(

Through lots of twiddling with settings (which I now cannot remember) I did manage to get the spindle to be somewhere near the correct Mach3 entered speeds for the low speed pulley but speed control was not linear and was way off for the high speed pulley (only two pulleys on my mill) despite me trying everything I could think of.
Note that Mach3 via the PP is always in complete, accurate, control of the spindle speed and I never have to tell it that I have changed pulleys.

It appears to me that (with the SS connected) Mach3 does not have any control over the speed entered whatsoever, despite it receiving and showing the actual spindle speed. I have tried all the suggestions for SS settings but none of them fix the problem.
Why the heck it has to be so arcane is beyond me...  ??? Surely someone can give me a complete list of Mach3 and SS versions, and settings for both, that WORK!

I'm seriously thinking of junking the SS and buying one of these (http://cncdrive.com/UC300.html) and maybe buying their software too (http://cncdrive.com/UCCNC.html)

9
Did you ever get the USB SmoothStepper to control spindle speed or did you give up on it too?
Hi Bill,
Not yet, I had to suspend investigations due to my breakout board deciding it didn't want to play ball. I'm waiting for its replacement to arrive before I will be able to get back to it.

Cheers,
Dave.

10
Jeff,
Did you get around to looking at the file I posted?
Since then I have tried every combination of ports/pins/settings I can think of, with no fix.
I have followed a couple of suggestions/documents that were posted by others with similar problems but they didn't help at all.

I hooked my mill back up to my old desktop PC parallel port (bypassing SS of course) and it all works fine - total, accurate spindle control at whatever speed I enter.
As mentioned before, I can see Mach3 displaying the spindle speed but it is not stable.
I use Windows XP Pro on two PC's, one a desktop and the other a laptop, the problem I am getting is when I use the laptop. I will try running USB SS from the desktop machine to see what results I get from that.

Please have a look at my uploaded file and let me know if you if it's OK or not.

Thanks,
Dave.

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