Realtime interfaces, remote manipulator, etc

[jodhner]

I'm a developer. I'm not familiar with Mach, I am familiar with manual G-code programming (professionally 20 years ago) and PC programming (bachelors degree 5 years ago). I have and use Sherline CNC mills and lathes.

I'm wanting to make applications that directly control a mill or other machine, without having to use G-code, or have intermediate files etc.

For example, a window on the screen that you can write in with a digitizer tablet, and have the mill follow the moves immediately. Or more generally, an interface that accepts simple coordinates, and maybe applies safety limits for limits and speeds, and does some buffering.

Is there such an interface in Mach?

Another application would be intuitive realtime control of a mill emulating geometric chucks, lathes and pens. (Basically really complicated Spirographs).

It is mandatory that this be realtime for many reasons.

Any leads or ideas? What tools and interfaces does Mach have that might work?

Thanks,
--Justin

[PoppaBear10]

Define Real time?

If you mean is Mach3 real time, then no it is not, it currently runs in a 10 hrts main update loop, with an optional faster 40 hrts update loop for fast small code.

If you mean real time possible at the machine, well yes, in a way. For instance the External Motion Card made by Galil, has buffer that Mach can load, so the board is always moving through its commands in real time in relation to the machine.

What you wanting todo...... You can implement some of what you want in a plug in that has your own custom device context that you translate those things to G code or DDAs to send out to a motion board....... Your writing "Tablet" could really just end up being a type of "Jog Pendant", in which in the config for that tablet and asociated Jog type plugin that you would do, you could have the machine follow your X/Y motion from the tablet, Scaling the tablets space to the equiveent machine softlimits, and Velocitys of your stylist in moves could not be faster than your machine could move....etc.

good luck to you,

scott

[mactec54]

Hi Jodhner

Some were on the Zone this was being done there also is one that uses a laser that the machine can follow

If you want to see a real time control look up Softservo & you will find that there control
is the best there is in the market today there lastest Canopen is the first in the world for CNC machines no hardware needed just computer drives & motors

[jodhner]

Sorry for the confusion, I should have been more thoughtful in the use of the term "real time". I think you figured out what I meant.

When I say "real time", I'm referring to the user interface and its relation to the motions of the machine. Move the pen, the machine moves in "real time" as perceived by the user. Latency only has to be sufficient to not be overly noticeable by a human.

"translate those things to G code or DDAs"

What is a DDA? (quick google . . . ) "Digital differential analyzer"? Are DDAs increments fed to the DDA? What form does the DDA interface take, where is this interface, and what is it called? What programming platforms can be used to access the DDA interface?

Let's say I have an application that operates on a few parametric equations and some user input, and the result is a set of coordinates every few milliseconds. I figure out what the increments are and send them to the DDA.

Is this right? Is there documentation on the data flow somewhere? What is the difference between using G-code, and "DDAs", besides the format of the data?

Thanks for your help.

--Justin

[jodhner]

I found this on DDAs:
http://www.machsupport.com/MachCusto...device_control

These are a little too low level for my needs, but they do look interesting.

What is the next layer down from G-codes? Is there a public intereface there?

I can send many, many G01 commands, if that can be done "real time" (human perception real time, not OS real time) but that seems inellegant. Do robiticists use G codes when they use Mach?

Thanks,
--Justin

[PoppaBear10]

Justin,

Look up, and download the Plug in sources for the "G-Rex", and the "Galil", (I dont remember if the source for the NC Pod is avail or not). Further, you can ask "Dave" of Dave Controls (see the Mach Yahoo group), who has done/doing a plug in for the Animatics "Smart motors". You can also ask Greg of Smooth Stepper, to perhaps at least tell you what kinda control Mach is feeding his board. All of these guys have driven external motion boards from Mach 3.

One note though, no matter WHAT your driving, you will have to use Machs Trajectory planner. I think the NC pod guy has Mach3, send him G-Codes directly from the running window into a buffer. BUT, you would also have to do some work to keep the whole thing "In synch".

scott

[jodhner]

Hi Scott,
Thanks for you help.

Is there a block diagram showing the major components of Mach? Something that shows how the trajectory planner is related to the various input and output interfaces? And how it is related to feedback? It might help me formulate my questions.

If there is an interface that accepts G-code commands one at a time, from Flash, Basic or other auxiliary platforms, that would probably do what I need. But if using that interface requires me to take on the responsibility for feedback, then it probably is not what I'm looking for.

Are there other input formats besides G-code that have the same functionality? I see that there is a gcode structure -- is it accessible from Flash and or Basic modules?

If you are interested . . .
This is a link to "A Brief Account of Ibetson's Geometric Chuck":
http://www.wkfinetools.com/z_tDownL/...#39;sChuck.asp

Thanks,
--Justin

[ger21]

You can send g-codes using VB. What Scott's talking about involves writing a plugin in C or whatever variant of C (C+?) that Mach3 uses.

[Al_The_Man]

I am not sure of your application, but if you want a motion that is controlled by a manual or machine operated pointing device directly, then any Galil card can be used in either Gearing or Cam modes in order to trace by following an externally directed motion.
If you wanted keyed in data input also, you would have to come up with a MMI or equivalent input.
This could be a stand alone unit or PC based, depending on the extent of the application.
A tracer would be an example of this application.
Al.

[PoppaBear10]

Answers below:

Is there a block diagram showing the major components of Mach? Something that shows how the trajectory planner is related to the various input and output interfaces? And how it is related to feedback? It might help me formulate my questions.

>> No!!! Mach3 is SEVERLY lacking in the Plugin areana, it is mostly LEARN by Sever PAIN..... I have written over 75 plugins as of last count, for this or that app, and each time you have to Find/guess what this or that does (for new stuff that you dont know yet), by trial and error.....

If there is an interface that accepts G-code commands one at a time, from Flash, Basic or other auxiliary platforms, that would probably do what I need. But if using that interface requires me to take on the responsibility for feedback, then it probably is not what I'm looking for.

>>THREE OPTIONS below:

>>Option #1

>> Mach will take 3 different forms to drive an external motion board:
1). Send G/M code Commands to your board (you have to implement a parser/interpreter.
2). Send steps per ms in to a Buffer on yoru board, recommended buffer size is around 1.25-2 seconds of time.
3). DDA's only the Grex (no defunct), used these, very much a pain in the butt, most use the 1 or 2 above.

In ALL cases above, you will need to have the BUFFER on your board, since machs loop time is currently 10hrtz. Also, you will need to handle all motion and feed back on yoru board.

>>>>>OPTION 2!!:

There is a "Mach Remote" plugin available freely downloadable from the mach site, it is the Mach3 Object model, and you can write your OWN front End/HMI program and send Motion calls to the mach engine to run your machine.

So Technically you will run your own "Screen/Application" launched from the plugin, how you parse what you send would be upto you, ie. you would translate yoru tablet moves in your plugin app, to G code then send that code into Mach3, in a case like this, I would probably launche your plugin, in its own thread, so you can handle smooth buffereing.

I have done the remote plugin just to play with it, and it works, there are a few bugs, that you have to work around, but they have been discovered and documented in the Plugin section thread on Mach3 support site. I personanally didnt pursue it much futher than playing with it, since didnt really have a customer need for that....

>>>>Option #3, if your a good programmer, you could probably attach to machs object as a resource from some other Programming enviroment like C#, VB, Flash, Etc. I have NOT been brave enough to attemp that one yet...

Are there other input formats besides G-code that have the same functionality? I see that there is a gcode structure -- is it accessible from Flash and or Basic modules?

>>> see answers above.......

If you are interested . . .
This is a link to "A Brief Account of Ibetson's Geometric Chuck":
http://www.wkfinetools.com/z_tDownL/...#39;sChuck.asp

Thanks,

[andy55]

did you consider EMC2? It is free, open-source and you could probably write a GUI for it to do what you want. Unlike most commercial software the inner workings of EMC2 are at least roughly documented in the manuals, and the source-code for everything is ofcourse available for study.
http://www.linuxcnc.org/