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Author Topic: Mach3 - MPG - Precise control as it is on an industrial CNC...  (Read 464 times)

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Offline ger21

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Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #10 on: June 15, 2019, 08:09:47 AM »
Thanks for all the information guys.  Frankly this is very disappointing.  Being that MACH 4 is promoted more as a industrial control I would have expected that this would have been resolved. 


This is one of my biggest issues with Mach4. No matter how good the software is, you have to rely on the hardware supplier to make it work.
Gerry

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Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #11 on: June 15, 2019, 09:30:57 AM »
Hi,

Quote
This is one of my biggest issues with Mach4. No matter how good the software is, you have to rely on the hardware supplier to make it work.

Doesn't that apply to ALL Windows CNC software?

What you are talking about is the realtime supports that the controller manufacturer builds into his board. If he, like CSLabs built
in realtime MPG to step/direction then all well and good, if not then there is the buffering delay.

Presumably you could build an even more sophisticated controller that does more and more in realtime, in fact if it
did it all then there would be no need for a Windows PC at all! That would certainly cure the buffering problem. ::)

To OP: if you want genuine realtime performance not just of jogging but ALL motion then:
1) Use LinuxCNC
2) Use a dedicated industrial controller.

If however you are concerned only with MPG performance then Hood has outlined a solution....CSMIO.

Craig
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     and I miss him!

Offline ger21

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Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #12 on: June 15, 2019, 09:42:49 AM »
Quote
Doesn't that apply to ALL Windows CNC software?

No. I'm talking about all features.
If Artsoft adds a new feature tomorrow, how long until it works in the ESS, or with a CS labs board? Months, if at all?

If CNC Drive adds a feature to UCCNC, they update the firmware at the same time and it works when it's released, on all their hardware platforms.
Same thing with every other windows control, as everyone else develops both hardware and software together.

Mach4 was released about 5 years ago. The ESS still doesn't support every feature, does it?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #13 on: June 15, 2019, 09:49:49 AM »
Hi,

Quote
The ESS still doesn't support every feature, does it?

Well yes it does, although it does not handle jogging as the CSMIO does.

ESS (in Mach4) offers:
1) Realtime THC
2) Spindle PID
3) Baklash Comp
4) Single point Lathe Threading
5) Laser Rastering/Vectoring
Plus all the usual homing/limits/gantry squaring/probing that we assume all controllers can manage.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #14 on: June 15, 2019, 12:13:55 PM »
how well does UCCNC handle jogging and the mpg?

Offline Hood

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Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #15 on: June 17, 2019, 02:57:59 PM »
Did a quick vid today to show the CSMIO and MPG. This is the X axis, set to x100 which means each click is 1mm and a full turn of the MPG gives exactly that.
https://www.youtube.com/watch?v=uh5D5hpipH4&feature=youtu.be
Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #16 on: June 18, 2019, 04:16:36 PM »
I like that video - that is what I expect a CNC machine to do when using the MPG!

I don't really care to dispute the capabilities of Windows, real time, non-real time, Linux etc.

I do know this, with Mach 3 using either the parallel port or using an external motion control card, they are doing real time pulse streams to the stepper / servo drives, this has been done for a very long time with the Mach software.  Based on that, I fail to understand the "real time" issues related to Windows. 

To me, it is a feature and capability of the MACH software that simply never has functioned properly.  It is a feature that is presented and promoted, but never clarified with a disclaimers stating "the MPG feature sort of works, but not really, but it could work if you bought this controller card, but it won't work with the parallel port or any other motion control card, so, be informed, this feature will only work if you buy this particular motion control card .... blah, blah, blah."

Don't get me wrong, I am not bashing MACH, to this day I find it absolutely amazing what it can do.

Chris D
Re: Mach3 - MPG - Precise control as it is on an industrial CNC...
« Reply #17 on: June 19, 2019, 03:38:12 AM »
Hi,

Quote
this has been done for a very long time with the Mach software.  Based on that, I fail to understand the "real time" issues related to Windows. 

Mach, or indeed any program on a PC, does not run continuously. It will run for a few milliseconds and then Windows will rush away
and do anther job or even several jobs and then come back to Mach and run for a few more milliseconds. This is the nature of
Windows and little or nothing you can do about it.

Your steppers/servos require non-interrupted pulse streams, the machine would stutter and stall if it relied on Mach alone
to generate pulse streams given that Mach runs 'in fits and starts'. For this reason Mach builds up a string of moves
and stores them in a buffer so while Mach is idle waiting for CPU time the motion controller 'has something to go on with'.

Its that 'something to go on with' that characterizes ALL Windows based CNC programs. While it works pretty well,
jogging in response to an MPG is one area where the 'something to go on with' idea catches you out.
The CSMIO works as well as it does because it can directly process MPG pulses to step/direction pulses without Machs
intervention. It is however the only controller that does that, to the best of my knowledge, and until Hood pointed it out
I didn't know that.

All the genuine realtime hardware controllers are very expensive, ten times and more what Mach costs.

LinuxCNC however is free and the hardware required is modestly priced. I personally am not a fan of Linux but you may
differ.

I use a VistaCNC P1A pendant, first with Mach3 and then with Mach4. The pendant is USB connected to the PC and has its
own plugin. In response to the pendants plugin Mach plans moves and communicates them to my ESS which in turn
generates the pulse streams required to move the axes. I have no trouble, if I select 0.1mm per click, the axes move 0.1mm
per click. What can happen if I select 1mm per click and spin the MPG fast the 'clicks stack up' faster than the machine can move,
and the machine runs on after I have stopped spinning the MPG to catch up on the backlog. It is very un-nerving. If I increase
the jog speed the machine can move that much faster an the problem is much reduced. I don't like that idea much, usually when I'm
jogging I want modest movement speeds to prevent overruns, inaccuracy and crashes. For this reason I tend not to use 1mm
per click, but I find 0.5mm per click or 0.1mm per click better matched to my machine speed and my brain function!

There is a thread running on the Mach4 board which talks a bit about Ethercat. Ethercat is essentially real time communication
for which Windows PCs have struggled because they are not real time capable. What changed here is a VERY clever
innovation provided by Interval Zero called RTX64 which adds a real time processing core to your existing Windows machine.
Further is sounds like its coming to Mach4 soon......and we hope affordably.

https://www.machsupport.com/forum/index.php?topic=41233.0

Whether it would solve your problem is not immediately clear to me but it might interest you.  Googling Interval Zero and
RTX64 will yield some very interesting and informative videos.

Craig

My wife left with my best friend...
     and I miss him!