GearHeads Forum

Hello,

Thank you makes sense...

I came up with a couple of questions during the night, mostly generic cnc ones, showing how much of a newbie I am.

1: Machine vs job coordinates. am I correct in assuming that machine coordinates are absolutes, and normally never changing coordinates, which might be used to implement soft limiots, while job coordinates allow you, for example, to place a smaller job in the middle of your machine and "temporary" (for the duration of the job) redefine the 0,0?

2: pulse generation. I am kind of shocked to learn that you send pulses to pokeys, I assumed that it would be able to generate the pulses forms directly from "move" commands, thus reducing greately the need for high bandwidth, high quality data channels. Does Auggie also need to handle accelerations/decelerations?

3: How do i create a "find probe" button to "zero" the z axis with the probe?

I will keep you informed of my progresses.
Thanks,
Cyrille

Hi C:

I came up with a couple of questions during the night, mostly generic cnc ones, showing how much of a newbie I am.

>> OK, shoot!

1: Machine vs job coordinat es. am I correct in assuming that machine coordinat es are absolutes, and normally never changing coordinat es, which might be used to implement soft limiots, while job coordinat es allow you, for example, to place a smaller job in the middle of your machine and "temporary" (for the duration of the job) redefine the 0,0?

>> Yes, machine coordinates are zeroed after a home, they never change after that.The normal view is of the "work"
coordinates which have a fixture offset applied. When you press ZERO you are generating a fixture offset the inverse
of machine coordinates that will then show you zero's. There are 255 fixture offsets, but typically you use only the one
in effect by default.

2: pulse generation. I am kind of shocked to learn that you send pulses to pokeys, I assumed that it would be able to generate the pulses forms directly from "move" commands, thus reducing greately the need for high bandwidth, high quality data channels. Does Auggie also need to handle accelerat ions/decelerations?

>> I dont send pulses, I send the number of steps to take in the next 1ms. I queue these up from a
trajectory planner programmed into Auggie. Move commands cannot blend if simply sent to a device.
Auggies trajectory planner is a 4 axis 6th order planner , in fact Auggie has 2 of them running at the
same time and allows one to drive 8 axis in total as 2 groups of 4 axis, or one group of 4 and 4 indivudual
axis with motion or constant speed. All accelerations and decelerations are dealt with in Auggie using
whatever you have set as a jerk limit. (Ideally you should set your acceleration very high on the motors
and then set a high JERK Limit, and then reduce the Jerk limit for proper operation when tuning the
motors. This is quite different to Mach3 or 4, but a jerk reduction planner works quite differently
in general. So in general Auggie is sending at a minimum 1000 motion commands per second and is
sending them even when your not in motion as a move of zero steps in the next millisecond.

3: How do i create a "find probe" button to "zero" the z axis with the probe?

  You cannot. I never turned on Probing in Auggie as I had no use of it. You are the second to ask for it,
I may add it one day, but its a lot of work if so far only 2 require it. I continue to evaluate that one.

Art

Hello,

>3: How do i create a "find probe" button to "zero" the z axis with the probe?
>  You cannot. I never turned on Probing in Auggie as I had no use of it.

Ha, now, this is a quite a problem for me as "zeroing" the Z axis is quite an important operation on a cnc machine...
I assumed that you had to use something similar to tune the "focus" for the laser. How do you set the laser distance/height in your use case scenarios?

Cyrille

Cyrille:

    I use the same technique I used in Mach3 on my router. I slow down the jog to
ridiculously slow and jog the Z down till it just touches. For the laser I use a block
and jog down till I can feel its a tight fit.

  There are times I want to move exactly a set distance, like say .1mm on my Z,
so for that I zero the dros', enter .1 in the Z, and then hit GotoZero.

  It wouldn't be too hard to make a panel that moves a set distance each press of a button,
OR to make a button that moves Z a set distance each press. I didnt turn on a probe
because I had no use for it. I do have a probe on my Mach3 driven Mill, but to be honest I
never use it, preferring instead to use jog for my zeroing.

  If I hear of many people wanting a probe I will look at turning it on, but its more complex
than one would think as I have to do it in the context of asking the pokeys to stop when it
sees the trigger of the probe and then reorient Auggie to that point in coordinate space. 
Its doable , just complex.  Probing is one of those things I found only like 1% of cnc
users used from my experience in Mach3. So, like G42 it doesn't exist in Auggie. One
of the design considerations in Auggie was to do away with what most didn't use, to make
it a more basic CNC driver. It can be argued each way whether that was right or wrong
in hindsight. I figured it would make the program less complex and easier to debug and
control.  Turns out Auggie is a bit more complex than Mach3 in those terms.. go figure,
sometimes the road to hell is paved with good intentions.

  That having been said, I use Auggie a fair bit and I find theres always a way to do
what I need. I use Mach3 a fair bit as well on my router table, but Auggie controls
two of my lasers. 

  Now if probing is important for zeroing, you may want to do it by adding 3 or
4 buttons, one with an end script calling for something like Engine.Feed( , , -5 );
to feed the Z down -5mm, another for -2, -1 and -.1 or even -.05 Then press the appropriate
buttons till a touchplate is touched. Its the oldschool way of touching off.

Art

Hello,

Maybe "probing" is not the right word to use as it seems to have another meaning in cnc world...

Pokeys has digital inputs. Is it possible to "read" these inputs from Auggie? You seem to be able to read at least some of the inputs (limits comes to mind...)

Could I use this to create a script that just goes down (slowly) until such input goes high?

while (digital_input_off)
{
  FeedTo(current_x, current_y, current_z+0.01mm);
}


Alternatively, Could I wire my "z0" probe to the z limit + and do a move until it reaches the limit?

Cyrille

Hi:

>>Alternatively, Could I wire my "z0" probe to the z limit + and do a move until it reaches the limit?

  Yes, you can do that , but an Estop will occur to end the probing. A limit will trip the Estop. Not a
problem really, but you will have top press reset to continue.

  The first idea will not work, this is because Auggie sends 1ms packets, so it may have a
seconds motion already sent any any time.

  You can read inputs and set outputs. They respond within a few ms generally, but are
not ensured to be in sync with motion.

Art

Hello,

So, really, I would need to move for 20ms at 1cm/s (=0.02mm), wait for 20ms or so, to make sure that the move is finished (is there a wait/Pause in your scripting language?).
Test the input and loop.Would that work?

Cyrille

Cyrille:

  Well, you wouldnt have to wait I guess, the process of switching to the script thread
and such will have at least a few ms delay, probably 100ms or so.  One of the problems is the
Engine.Feed is in absolute.. unless gcode has set it to incremental...hmmmm..

  Its been too long since Ive looked at it, Cyrille, Ill dig into the code
to see just how one could do a touchoff on an axis. I may be able
to add a simple type of move till hit routine as a script call or something...

  Give it a few days..

Art

 

Hello,

Thank you for doing/checking this, I truly appreciate the time that you are spending helping me...

I have another question. Do you have a ? list ? of the subset of code that auggie does support? I am asking as my cam tool does not produ?e code, but something quite close and I will need to program a ? transcoder ?...

Actually, this is a good question, can a ? load gcode ? ?vent trigger a script that could automatically execute an external program so that I would not need to manually run my transcoder on each tool path, but the transcoder would be automatically called by auggie? This is just a wild idea to improve user interface, there is no need for you to work on it or anyth8ng like this, I am just wondering if the right hooks and functionalities are in place in auggie or not.

Thanks,
Cyrille

Cyrille:

  The scripting language has quite a few system hooks so it can probably be done.
Im not sure theres an auto Gcode load event, but it is possible to add a button to
call a created dialog.. Watch the video on Dialog creation.. or the thread..I cant recall
how I did the tutorial on that subject.
  The Dialogs library shows some system call examples I think... Theres a lot
in there that could keep you busy for a long time.

  As to the Gcode subset, I believe its easiest to say it implements pretty much
what Mach3 has with the exception of probing, threading, and G43 type cutter
compensations. Pretty much everything else I think is there with few exceptions.
When not implemented, the normal operation is to either issue an error or look
for a script, in which case the log will tell you it tried.

Art