mach 4 development

[dharmic]

Ahhh.

Most people who own a vacuum cleaner don't care whether the motor is a universal type or synchronous AC single phase type. They don't care about the number of poles in the motor, the metallurgy of the axle and bearings, etc etc etc. They care that they can switch it on and clean their carpet.

If you compared two vacuum cleaners that looked and sounded identical, and then tried to say the one with the universal motor was much better than the one with the sync AC motor, most people would just shrug and let you get all religious ranty but stop listening and not care. They're the same. If you then tried to tell them that one had an offset gripley discombobulator simplexed to its axial offset vortex migrator they would probably just nod, smile and walk away.

Yes, people need to know that there are options. But if you need to go down to the guts of the architecture at a software engineer's level of understanding to see the difference then, for the people using the software, there effectively is no difference.

The processor workload of running a toolpath, even with on the fly curve matching and acceleration lookahead maths going on, even doing floating point all the way down, is utterly insignificant in the scope of modern microprocessors. If the machine has been built and OS installed purely for the purpose of running the machine control software, then it's idle 99.9% of the time and any OS will be pretty reasonable in terms of lag and latency. If the hardware is fast enough and the load low enough, pretty much anything approaches an RTOS in its external behaviour.

Windows is not a "real-time system". Mach3 is an application, noth part of the OS. It comes with some drivers, which are not part of the OS. Installing those drivers lets them run under supervision of the OS with a little more latitude and priority, but they are not part of the OS. Throwing hacks in at the driver level can make it a little less laggy and a little more deterministic, but it's still not a real-time system and never will be.

Linux is not a "real-time system" either, although I understand it can get extremely close with the right kernel mods. The ones LinuxCNC apparently uses in its build - and it looks like LinuxCNC is the full real time linux kernel with the CNC apps included in the install package.

So, from a software architecture/engineering point of view, LinuxCNC is by far and away closer to a RTOS but, as long as it works, no-one cares. Well, apart from those members who are bored and have enough computer science knowledge to be dangerous and really just want to have a d*ck swinging competition. I'd back this up with a CV of software blah blah blah but really don't care enough to argue. Sometimes it's easier to just say your piece and let people who disagree be wrong.

[dertsap]

any idea of how far off the next version of emc is ??

[samco]

Anyone priced a real-time kernel for windows?

any idea of how far off the next version of emc is ??

Close? Unless some major bug pops up I would guess a few weeks at the most.

Sam

[dertsap]

cool ! I will probably give it a go over on one of my mills .
Am I wrong or has it become much more lean from what it was in the past when emc2 was fairly fresh on ubuntu . It was an absolute hog when I was using it in the past , and it was the main reason I went to mach . My machine at the time ran much better with mach and I ended up sticking with it . I've recently downloaded linuxcnc and installed it on vmware (not connected to a machine) . It seems like it's much leaner and not so resource hungry .
I like my dumpster grade pc's

[daniellyall]

they will still argue with you mactec54 there are so many options out there that can be better than a window`s or linux based program. but I have tried both and on a dud computer both are useless, on a good computer both are fine, it`s only good if it does what you wont 24/7.

it is important for people to know what`s what the fact`s. just not the bit where people say no it`s not, what can be wrong.

but if it`s running solid states hard drives and that new fancy stuff it`s going to be fast anyway what ever computer you are using then you can argue about micro seconds.

[hanermo]

You are mistaken.

The mach3 PP driver is a real-time operating system, and as such is deterministic.
The app is mach3, and runs under windows.
The mach3 PP driver runs at ring0, and controls when windows is allowed to run.

The "linuxcnc" kernel is also a real time operating system, and as such is deterministic. Bog-standard linux (say debian, redhat whatever) are not real-time, but are low-latency.

And yes, it matters very much !
Because the mach3 system was built to support the PP driver, high-priority tasks like
- jogging and
- homing and
- threading and
- encoder and servo support then developed from this setup.
This is why, today, the hardware manufacturer like Cslabs (CSMIO-IP-S 4Mhz), Polabs (Pokeys +CNC, 125 kHz) then needs to support these tasks-
and they all do it differently, unfortunately.

For the same reason linuxcnc was built with a certain structure, and some things like
- rigid tapping
are easier supported with whatever interface hw you may have.
And some others, like glass scale support, may or may not be easier. (We need examples of working stuff !).

Windows is not a "real-time system". Mach3 is an application, noth part of the OS.
... drivers lets them run under supervision of the OS with a little more latitude and priority, but they are not part of the OS.

Linux is not a "real-time system" either, although I understand it can get extremely close with the right kernel mods. The ones LinuxCNC apparently uses in its build - and it looks like LinuxCNC is the full real time linux kernel with the CNC apps included in the install package.

[daniellyall]

well put Hanermo. you just get what you need

[dharmic]

Do you know what an operating system is, hanermo? Do you know what "real time" is?

Actually, no, I don't even care. You can educate yourself or be wrong, either way, no skin off my nose. Have fun.

[daniellyall]

A quantum computer would be real time maybe

[mactec54]

Anyone priced a real-time kernel for windows?

Been using it for just over 14 years, it comes as part of the control package, so there is no why of knowing how much the cost is

[samco]

People are touching on one of the big differences.. With mach you have to buy the external motion controller that has the features that you need. (Or hope that the feature you want will be added in the future...)

Linuxcnc being the motion controller - all features added to linuxcnc (like rigid tapping or gear hobbing) are available to all interfaces. Even the printer port. Plus you have access to the linuxcnc real-time subsystem (HAL) and can build your own logic easily. Wait - there is more - you have linuxcnc's integrated ladder which is also running real-time.

Because linuxcnc isn't buffered system - you don't have to work around issues like feed hold delays or feedrate override delays. Those features would have to be implemented in the motion controllers hardware to be real-time in those systems. In linuxcnc they are in the computer real-time motion controller.


Sam

[A_Camera]

Here's some info written by the author of Mach3:


http://nv50.0fees.net/Doc/Mach3Mysteries.pdf

Thank you. Interesting read. It is a very well written software, works well and I am happy with it.

BTW, there is not the slightest indication that there is anything written in assembly language, quite the opposite, it is pretty clear c++ work, which considering the complexity and the developments in computer speeds, is a very much understandable option.

[A_Camera]

well put Hanermo. you just get what you need

Right.

...but he keeps calling the PP driver a real-time operating system, which it obviously is not and he says that Mach3 controls Windows when it is actually the opposite. Of course, Mach3 can crash Windows, but that's not the same as it controls it.

[Tkamsker]

I guess now it is clear that almost everyone is > 30 years in it .. nice and because it is not an it Forum isnt it cool that mach seems to work well over years when it's the only thing the machine does and the Hardware is Close to Standard ? Even if it is not real time Who cares if it is fast Enough ?
...

Gesendet von meinem SM-N9005 mit Tapatalk

[A_Camera]

isn't it cool that mach seems to work well over years when it's the only thing the machine does and the Hardware is Close to Standard ? Even if it is not real time Who cares if it is fast Enough ?

Was exactly my point as well. Maybe not generally about Mach, I don't know how well Mach4 works, but Mach3 works definitely well even in an old computer, and in a crappy computer it doesn't really matter if you run Linux or Windows, none of them will work well. When I initially started my CNC build project I though of reusing a miniature industry PC because I have a few of those and because they are small and very robust. I tried with Windows XP pro and Mach3, but had some issues with the speed, so I dumped the idea, installed Linux but LinuxCNC was also struggling so I had to dump the idea of using that PC, it was simply too crappy. There is a lower limit, and once that is reached it doesn't really matter what operating system or CNC software you are using, and the same is true upwards, if you have a good computer it works just as well with both. So just for the sake of "real time OS" it is totally pointless to go for LinuxCNC. For religious reasons or any other imaginary or real reasons it is another thing, but fact is fact, Mach3 works just as well.

[samco]

Mach4 running roadrunner flat out (config 500ipm 30in/s^2) - and stated mach4 has no path control yet.



Mach3 same settings



Linuxcnc has path following control so you can easily specify how close you want the machine to follow programed path.

G Codes

Sam

[daniellyall]

that just shows linux cnc those picks do not prove anything.

if you tune M3 properly it does stick to the cut path. M4 has not got the same path control as M3 it has not been finished/added/done yet cant quite compare it properly. when I have use all 3 there is Fa differences between the cut path`s or what it shows on a computer screen.

yes feed hold stop`s at the end of the line that its on in M3 in M4 it stop`s when you push the feed hold button. linuxcnc yes feed hold when you push the button.

stop in M3, M4 and linuxcnc when button is pushed.

soft limits work ok in M3, perfect in M4 and linuxcnc.

homing fine for all if set correctly.

using any off them on a simple router with a simple stepper driver and a good computer they are all fine. M4 a tickell better, linuxcnc 2.6 about the same as M3 minus the known problems.

linuxcnc 2.7 will be better than M3 that`s been proven by tormach and another person who converted a novacon mill to pathpilot, discounting mistakes in updates that get fixed in the next update

no one has done a proper comparison between linuxcnc 2.7 and M4 yet, so dont go there.

I have use all 3 on the same machine running the same speed`s and feeds same file was used for testing roadrunner, the differences was bugger all some things just worked better other`s worse.

so in general you get the one that has what you wont if it does all of what you wont how you expected it to and works 24/7 with no problems, then that`s all good.

so saying one is better than the other is not quite correct if it does not do something well that you wont it to do then its no good what ever program it is.

all of the above has been my experiences with each program. I will be moving away from M3 when I find something that is a lot better be it M4, linuxcnc 2.7, pathpilot, pokeys, other.

also what would you define as real time ???????

[ger21]

if you tune M3 properly it does stick to the cut path.

By "properly", do you mean slower and slower until it does? Because going slower is the only way to force Mach3 to accurately follow a path

M4 has the same path control as M3 at this time.

No, Mach4 has NO control. Mach3 has several CV options that provide varying levels of control.

[daniellyall]

yes depending on cut type for 3D cut paths I have a slower feed and speed learnt that from you gerry,(learnt most of what I know from you and I listen to you) there is no other way to do it that I have found. for 2D I have a faster profile. I tune the **** out of M3 so at 1000 moves depending on cut type its bang on. this is on my big machine. it`s max speed is 1250 mm/min to be bang on, slower it get`s better and better but 1250 is good at 1000 move`s

on the small one it`s max speed is 600mm/min so it`s fine what ever cut is being done and what ever program I have tried, it`s fine

ok thanks for correction gerry, put the correction in.

[samco]

The screenshots are of linuxcnc plotting the motion of mach3/4. Using mesa hardware counting step/dir.